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Piktel JS, Wan X, Kouk S, Laurita KR, Wilson LD. Beneficial Effect of Calcium Treatment for Hyperkalemia Is Not Due to "Membrane Stabilization". Crit Care Med 2024; 52:1499-1508. [PMID: 39312458 PMCID: PMC11410510 DOI: 10.1097/ccm.0000000000006376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
OBJECTIVES Hyperkalemia is a common life-threatening condition causing severe electrophysiologic derangements and arrhythmias. The beneficial effects of calcium (Ca 2+ ) treatment for hyperkalemia have been attributed to "membrane stabilization," by restoration of resting membrane potential (RMP). However, the underlying mechanisms remain poorly understood. Our objective was to investigate the mechanisms underlying adverse electrophysiologic effects of hyperkalemia and the therapeutic effects of Ca 2+ treatment. DESIGN Controlled experimental trial. SETTING Laboratory investigation. SUBJECTS Canine myocytes and tissue preparations. INTERVENTIONS AND MEASUREMENTS Optical action potentials and volume averaged electrocardiograms were recorded from the transmural wall of ventricular wedge preparations ( n = 7) at baseline (4 mM potassium), hyperkalemia (8-12 mM), and hyperkalemia + Ca 2+ (3.6 mM). Isolated myocytes were studied during hyperkalemia (8 mM) and after Ca 2+ treatment (6 mM) to determine cellular RMP. MAIN RESULTS Hyperkalemia markedly slowed conduction velocity (CV, by 67% ± 7%; p < 0.001) and homogeneously shortened action potential duration (APD, by 20% ± 10%; p < 0.002). In all preparations, this resulted in QRS widening and the "sine wave" pattern observed in severe hyperkalemia. Ca 2+ treatment restored CV (increase by 44% ± 18%; p < 0.02), resulting in narrowing of the QRS and normalization of the electrocardiogram, but did not restore APD. RMP was significantly elevated by hyperkalemia; however, it was not restored with Ca 2+ treatment suggesting a mechanism unrelated to "membrane stabilization." In addition, the effect of Ca 2+ was attenuated during L-type Ca 2+ channel blockade, suggesting a mechanism related to Ca 2+ -dependent (rather than normally sodium-dependent) conduction. CONCLUSIONS These data suggest that Ca 2+ treatment for hyperkalemia restores conduction through Ca 2+ -dependent propagation, rather than restoration of membrane potential or "membrane stabilization." Our findings provide a mechanistic rationale for Ca 2+ treatment when hyperkalemia produces abnormalities of conduction (i.e., QRS prolongation).
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Affiliation(s)
- Joseph S Piktel
- Department of Emergency Medicine, Emergency Care and Research and Innovation, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Xiaoping Wan
- Department of Physiology & Cell Biology, The Ohio State University, College of Medicine, Columbus, OH
| | - Shalen Kouk
- Orthopedic Surgery and Sports Medicine, Mercy Clinic, St. Louis, MO
| | - Kenneth R Laurita
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Lance D Wilson
- Department of Emergency Medicine, Emergency Care and Research and Innovation, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
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2
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Laurita KR, Piktel JS, Irish L, Nassal M, Cheng A, McCauley M, Pawlowski G, Dennis AT, Suen Y, Almahameed S, Ziv O, Gourdie RG, Wilson LD. Spontaneous Repolarization Alternans Causes VT/VF Rearrest That Is Suppressed by Preserving Gap Junctions. JACC Clin Electrophysiol 2024; 10:1271-1286. [PMID: 38752959 DOI: 10.1016/j.jacep.2024.03.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 03/01/2024] [Accepted: 03/07/2024] [Indexed: 06/25/2024]
Abstract
BACKGROUND Ventricular tachycardia (VT)/ventricular fibrillation (VF) rearrest after successful resuscitation is common, and survival is poor. A mechanism of VT/VF, as demonstrated in ex vivo studies, is when repolarization alternans becomes spatially discordant (DIS ALT), which can be enhanced by impaired gap junctions (GJs). However, in vivo spontaneous DIS ALT-induced VT/VF has never been demonstrated, and the effects of GJ on DIS ALT and VT/VF rearrest are unknown. OBJECTIVES This study aimed to determine whether spontaneous VT/VF rearrest induced by DIS ALT occurs in vivo, and if it can be suppressed by preserving Cx43-mediated GJ coupling and/or connectivity. METHODS We used an in vivo porcine model of resuscitation from ischemia-induced cardiac arrest combined with ex vivo optical mapping in porcine left ventricular wedge preparations. RESULTS In vivo, DIS ALT frequently preceded VT/VF and paralleled its incidence at normal (37°C, n = 9) and mild hypothermia (33°C, n = 8) temperatures. Maintaining GJs in vivo with rotigaptide (n = 10) reduced DIS ALT and VT/VF incidence, especially during mild hypothermia, by 90% and 60%, respectively (P < 0.001; P < 0.013). Ex vivo, both rotigaptide (n = 5) and αCT11 (n = 7), a Cx43 mimetic peptide that promotes GJ connectivity, significantly reduced DIS ALT by 60% and 100%, respectively (P < 0.05; P < 0.005), and this reduction was associated with reduced intrinsic heterogeneities of action potential duration rather than changes in conduction velocity restitution. CONCLUSIONS These results provide the strongest in vivo evidence to date suggesting a causal relationship between spontaneous DIS ALT and VT/VF in a clinically realistic scenario. Furthermore, our results suggest that preserving GJs during resuscitation can suppress VT/VF rearrest.
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Affiliation(s)
- Kenneth R Laurita
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA.
| | - Joseph S Piktel
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA; Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Laken Irish
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Michelle Nassal
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Aurelia Cheng
- Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Matthew McCauley
- Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Gary Pawlowski
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Adrienne T Dennis
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yi Suen
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA; Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Soufian Almahameed
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ohad Ziv
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
| | - Robert G Gourdie
- Fralin Biomedical Research Institute, Virginia Tech University, Roanoke, Virginia, USA
| | - Lance D Wilson
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA; Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
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3
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Li L, Ye W, Li Y, Chen Y, Zeng J. Intraoperative accidental hypothermia as a probable cause of malignant ventricular arrhythmias in an elderly patient undergoing transurethral resection of prostate: A case report. Heliyon 2023; 9:e19006. [PMID: 37600405 PMCID: PMC10432956 DOI: 10.1016/j.heliyon.2023.e19006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 07/23/2023] [Accepted: 08/04/2023] [Indexed: 08/22/2023] Open
Abstract
Background Intraoperative hypothermia is a common but severe condition that is defined as a core body temperature below 36 °C. Accidental hypothermia can produce coagulopathy, immunosuppression and peripheral hypoperfusion that can ultimately lead to life-threatening ventricular arrhythmias and vital organ injury, and it is significantly associated with perioperative complications and mortality. Case description We report the case of an 82-year-old man who presented with persistent ventricular tachycardia intraoperatively due to accidental hypothermia. The patient was diagnosed with benign prostatic hypertrophy and scheduled for transurethral resection of the prostate. Laboratory tests showed moderate anemia, and echocardiography indicated mild tricuspid and mitral regurgitation. The patient received general anesthesia with endotracheal intubation. Four hours after the start of surgery, the patient developed sudden ventricular tachycardia with severe hypotension. Arterial blood gas sampling indicated that there was no disturbance of electrolytes, acid-base balance or excessive bleeding. The rectal temperature was measured immediately, and the core temperature was 32 °C. The patient received antiarrhythmic therapy and rewarming measures. No additional ventricular arrhythmias appeared after the core temperature rose to 35 °C and the blood pressure returned to normal. The patient was transferred to the intensive care unit after surgery for further observation and was moved to the general ward the next day. He was discharged 4 days later without significant organ damage. Conclusions Intraoperative hypothermia may increase ventricular arrhythmia risk, especially in elderly patients. Surgeons and anesthesiologists should pay more attention to preventing and reversing accidental hypothermia, necessitating aggressive efforts to maintain normothermia during surgery.
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Affiliation(s)
| | | | - Yongxing Li
- Department of Anesthesiology, The Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yingzhen Chen
- Department of Anesthesiology, The Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jianfeng Zeng
- Department of Anesthesiology, The Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
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Hosseini S, Salari S, Banar S, Rezaei Y, Tajik A, Zahedmehr A, Emkanjoo Z. Hypothermia-induced accelerated idioventricular rhythm after cardiac surgery; a case report. BMC Cardiovasc Disord 2023; 23:142. [PMID: 36941559 PMCID: PMC10026505 DOI: 10.1186/s12872-023-03178-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 03/09/2023] [Indexed: 03/23/2023] Open
Abstract
BACKGROUND Accelerated idioventricular rhythm (AIVR) is a slow ventricular arrhythmia, commonly due to myocardial ischemia in coronary artery disease. It is a transitory rhythm that rarely causes hemodynamic instability or necessitates any specific therapy. Besides, the common predisposing factors for ventricular arrhythmias after open-heart surgery are hemodynamic instability, electrolyte imbalances, hypoxia, hypovolemia, myocardial ischemia and infarction, acute graft closure, reperfusion injury, and administration of inotropes and antiarrhythmic drugs. Here we report a case of AIVR after cardiac surgery, mostly due to hypothermia that to our knowledge, it is the first report. CASE PRESENTATION We describe a 76-year-old man presenting with typical chest pain. Following routine investigations, the patient underwent coronary artery bypass grafting. Postoperatively, he was transferred to the intensive care unit with good hemodynamic status. However, about 3 h later, he developed rhythm disturbances, leading to hemodynamic instability without response to volume replacement or inotropic support. His rhythm was AIVR, although, at first glance, it resembled the left bundle branch block. Given his unstable hemodynamic status, he was emergently transferred to the operating room. Cardiopulmonary bypass (CPB) was resumed for hemodynamic support. After the patient was rewarmed to about 35 ºC, AIVR returned to normal. He was weaned from CPB successfully and with an uneventful hospital course. CONCLUSIONS Hypothermia is a potential cause of rhythm disturbance. Preventing the causes of arrhythmias, including hypothermia, is the best strategy.
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Affiliation(s)
- Saeid Hosseini
- Heart Valve Diseases Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, 1995614331, Iran
| | - Soheila Salari
- Heart Valve Diseases Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, 1995614331, Iran.
| | - Sepideh Banar
- Heart Valve Diseases Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, 1995614331, Iran
| | - Yousef Rezaei
- Heart Valve Diseases Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, 1995614331, Iran
| | - Atieh Tajik
- Heart Valve Diseases Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, 1995614331, Iran
| | - Ali Zahedmehr
- Cardiovascular Intervention Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, 1995614331, Iran
| | - Zahra Emkanjoo
- Cardiac Electrophysiology Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, 1995614331, Iran
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Wisløff‐Aase K, Skulstad H, Haugaa K, Lingaas PS, Beitnes JO, Halvorsen PS, Espinoza A. Myocardial electrophysiological and mechanical changes caused by moderate hypothermia-A clinical study. Physiol Rep 2022; 10:e15259. [PMID: 35439365 PMCID: PMC9017970 DOI: 10.14814/phy2.15259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023] Open
Abstract
Moderate hypothermia has been used to improve outcomes in comatose out-of-hospital cardiac arrest survivors during the past two decades, although the effects remain controversial. We have recently shown in an experimental study that myocardial electrophysiological and mechanical relationships were altered during moderate hypothermia. Electromechanical window positivity increased, and electrical dispersion of repolarization decreased, both of which are changes associated with decreased arrhythmogenicity in clinical conditions. Mechanical dispersion, a parameter also linked to arrhythmic risk, remained unaltered. Whether corresponding electrophysiological and mechanical changes occur in humans during moderate hypothermia, has not been previously explored. Twenty patients with normal left ventricular function were included. Measurements were obtained at 36 and 32°C prior to ascending aortic repair while on partial cardiopulmonary bypass and at 36°C after repair. Registrations were performed in the presence of both spontaneous and comparable paced heart rate during standardized loading conditions. The following electrical and mechanical parameters were explored: (1) Electromechanical window, measured as time difference between mechanical and electrical systole, (2) dispersion of repolarization from ECG T-wave, and (3) mechanical dispersion, measured as segmental variation in time to peak echocardiographic strain. At moderate hypothermia, mechanical systolic prolongation (425 ± 43-588 ± 67 ms, p < 0.001) exceeded electrical systolic prolongation (397 ± 49-497 ± 79 ms, p < 0.001), whereby, electromechanical window positivity increased (29 ± 30-86 ± 50 ms, p < 0.001). Dispersion of repolarization and mechanical dispersion remained unchanged. Corresponding electrophysiological and mechanical relationships were present at comparable paced heart rates. After rewarming, the increased electromechanical window was reversed in the presence of both spontaneous and paced heart rates. Moderate hypothermia increased electromechanical window positivity, while dispersion of repolarization and mechanical dispersion remained unchanged. This impact of hypothermia may be clinically relevant for selected groups of patients after cardiac arrest.
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Affiliation(s)
- Kristin Wisløff‐Aase
- Institute of Clinical MedicineFaculty of MedicineUniversity of OsloOsloNorway
- Departments of Research and DevelopmentDivision of Emergencies and Critical CareOslo University HospitalOsloNorway
| | - Helge Skulstad
- Institute of Clinical MedicineFaculty of MedicineUniversity of OsloOsloNorway
- ProCardio Centre for InnovationDepartment of CardiologyOslo University HospitalOsloNorway
- The Intervention CentreOslo University HospitalOsloNorway
| | - Kristina Haugaa
- ProCardio Centre for InnovationDepartment of CardiologyOslo University HospitalOsloNorway
- Karolinska Institute and Cardiovascular DivisionFaculty of MedicineKarolinska University HospitalStockholmSweden
| | | | - Jan Otto Beitnes
- ProCardio Centre for InnovationDepartment of CardiologyOslo University HospitalOsloNorway
| | - Per Steinar Halvorsen
- Institute of Clinical MedicineFaculty of MedicineUniversity of OsloOsloNorway
- The Intervention CentreOslo University HospitalOsloNorway
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6
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Mohyuddin R, Dietrichs ES, Sundaram P, Kondratiev T, Figenschou MF, Sieck GC, Tveita T. Cardiovascular Effects of Epinephrine During Experimental Hypothermia (32°C) With Spontaneous Circulation in an Intact Porcine Model. Front Physiol 2021; 12:718667. [PMID: 34552506 PMCID: PMC8450451 DOI: 10.3389/fphys.2021.718667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 06/25/2021] [Indexed: 01/05/2023] Open
Abstract
Aims: Rewarming from accidental hypothermia and therapeutic temperature management could be complicated by cardiac dysfunction. Although pharmacologic support is often applied when rewarming these patients, updated treatment recommendations are lacking. There is an underlying deficiency of clinical and experimental data to support such interventions and this prevents the development of clinical guidelines. Accordingly, we explored the clinical effects of epinephrine during hypothermic conditions. Materials and methods: Anesthetized pigs were immersion cooled to 32°C. Predetermined variables were compared at temperature/time-point baseline, after receiving 30 ng/kg/min and 90 ng/kg/min epinephrine infusions: (1) before and during hypothermia at 32°C, and after rewarming to 38°C (n = 7) and (2) a time-matched (5 h) normothermic control group (n = 5). Results: At 32°C, both stroke volume and cardiac output were elevated after 30 ng/kg/min administration, while systemic vascular resistance was reduced after 90 ng/kg/min. Epinephrine infusion did not alter blood flow in observed organs, except small intestine flow, and global O2 extraction rate was significantly reduced in response to 90 ng/kg/min infusion. Electrocardiographic measurements were unaffected by epinephrine infusion. Conclusion: Administration of both 30 ng/kg/min and 90 ng/kg/min at 32°C had a positive inotropic effect and reduced afterload. We found no evidence of increased pro-arrhythmic activity after epinephrine infusion in hypothermic pigs. Our experiment therefore suggests that β₁-receptor stimulation with epinephrine could be a favorable strategy for providing cardiovascular support in hypothermic patients, at core temperatures >32°C.
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Affiliation(s)
- Rizwan Mohyuddin
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, Tromsø, Norway
| | - Erik Sveberg Dietrichs
- Experimental and Clinical Pharmacology Research Group, Department of Medical Biology, UiT, The Arctic University of Norway, Tromsø, Norway.,Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway
| | - Predip Sundaram
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, Tromsø, Norway
| | - Timofey Kondratiev
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, Tromsø, Norway
| | - Marie Fjellanger Figenschou
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, Tromsø, Norway.,Division of Surgical Medicine and Intensive Care, University Hospital of North Norway, Tromsø, Norway
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MI, United States
| | - Torkjel Tveita
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, Tromsø, Norway.,Division of Surgical Medicine and Intensive Care, University Hospital of North Norway, Tromsø, Norway.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MI, United States
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Filice M, Cerra MC, Imbrogno S. The goldfish Carassius auratus: an emerging animal model for comparative cardiac research. J Comp Physiol B 2021; 192:27-48. [PMID: 34455483 PMCID: PMC8816371 DOI: 10.1007/s00360-021-01402-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 08/09/2021] [Accepted: 08/18/2021] [Indexed: 12/12/2022]
Abstract
The use of unconventional model organisms is significantly increasing in different fields of research, widely contributing to advance life sciences understanding. Among fishes, the cyprinid Carassius auratus (goldfish) is largely used for studies on comparative and evolutionary endocrinology, neurobiology, adaptive and conservation physiology, as well as for translational research aimed to explore mechanisms that may be useful in an applicative biomedical context. More recently, the research possibilities offered by the goldfish are further expanded to cardiac studies. A growing literature is available to illustrate the complex networks involved in the modulation of the goldfish cardiac performance, also in relation to the influence of environmental signals. However, an overview on the existing current knowledge is not yet available. By discussing the mechanisms that in C. auratus finely regulate the cardiac function under basal conditions and under environmental challenges, this review highlights the remarkable flexibility of the goldfish heart in relation not only to the basic morpho-functional design and complex neuro-humoral traits, but also to its extraordinary biochemical-metabolic plasticity and its adaptive potential. The purpose of this review is also to emphasize the power of the heart of C. auratus as an experimental tool useful to investigate mechanisms that could be difficult to explore using more conventional animal models and complex cardiac designs.
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Affiliation(s)
- Mariacristina Filice
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036, Arcavacata di Rende, CS, Italy.
| | - Maria Carmela Cerra
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036, Arcavacata di Rende, CS, Italy
| | - Sandra Imbrogno
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036, Arcavacata di Rende, CS, Italy
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8
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Dietrichs ES, McGlynn K, Allan A, Connolly A, Bishop M, Burton F, Kettlewell S, Myles R, Tveita T, Smith GL. Moderate but not severe hypothermia causes pro-arrhythmic changes in cardiac electrophysiology. Cardiovasc Res 2021; 116:2081-2090. [PMID: 32031595 PMCID: PMC7584464 DOI: 10.1093/cvr/cvz309] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/08/2019] [Accepted: 02/04/2020] [Indexed: 12/15/2022] Open
Abstract
Aims Treatment of arrhythmias evoked by hypothermia/rewarming remains challenging, and the underlying mechanisms are unclear. This in vitro experimental study assessed cardiac electrophysiology in isolated rabbit hearts at temperatures occurring in therapeutic and accidental hypothermia. Methods and results Detailed ECG, surface electrogram, and panoramic optical mapping were performed in isolated rabbit hearts cooled to moderate (31°C) and severe (17°C) hypothermia. Ventricular activation was unchanged at 31°C while action potential duration (APD) was significantly prolonged (176.9 ± 4.2 ms vs. 241.0 ± 2.9 ms, P < 0.05), as was ventricular repolarization. At 17°C, there were proportionally similar delays in both activation and repolarization. These changes were reflected in the QRS and QT intervals of ECG recordings. Ventricular fibrillation threshold was significantly reduced at 31°C (16.3 ± 3.1 vs. 35 ± 3.5 mA, P < 0.05) but increased at 17°C (64.2 ± 9.9, P < 0.05). At 31°C, transverse conduction was relatively unchanged by cooling compared to longitudinal conduction, but at 17°C both transverse and longitudinal conduction were proportionately reduced to a similar extent. The gap junction uncoupler heptanol had a larger relative effect on transverse than longitudinal conduction and was able to restore the transverse/longitudinal conduction ratio, returning ventricular fibrillation threshold to baseline values (16.3 ± 3.1 vs. 36.3 ± 4.3 mA, P < 0.05) at 31°C. Rewarming to 37°C restored the majority of the electrophysiological parameters. Conclusions Moderate hypothermia does not significantly change ventricular conduction time but prolongs repolarization and is pro-arrhythmic. Further cooling to severe hypothermia causes parallel changes in ventricular activation and repolarization, changes which are anti-arrhythmic. Therefore, relative changes in QRS and QT intervals (QR/QTc) emerge as an ECG-biomarker of pro-arrhythmic activity. Risk for ventricular fibrillation appears to be linked to the relatively low temperature sensitivity of ventricular transmural conduction, a conclusion supported by the anti-arrhythmic effect of heptanol at 31°C.
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Affiliation(s)
- Erik S Dietrichs
- Experimental and Clinical Pharmacology, Department of Medical Biology, UiT, The Arctic University of Norway, 9037 Tromsø, Norway.,Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, Norway.,Divisions of Diagnostic Services and Surgical Medicine and Intensive Care, University Hospital of Northern Norway, Tromsø, Norway
| | - Karen McGlynn
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, UK
| | - Andrew Allan
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, UK
| | - Adam Connolly
- Division of Imaging Sciences & Biomedical Engineering, Department of Biomedical Engineering, Kings College London, UK
| | - Martin Bishop
- Division of Imaging Sciences & Biomedical Engineering, Department of Biomedical Engineering, Kings College London, UK
| | - Francis Burton
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, UK
| | - Sarah Kettlewell
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, UK
| | - Rachel Myles
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, UK
| | - Torkjel Tveita
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, Norway.,Divisions of Diagnostic Services and Surgical Medicine and Intensive Care, University Hospital of Northern Norway, Tromsø, Norway
| | - Godfrey L Smith
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, UK
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9
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Srinivasan NT, Garcia J, Schilling RJ, Ahsan S, Hunter RJ, Lowe M, Chow AW, Lambiase PD. Dynamic spatial dispersion of repolarization is present in regions critical for ischemic ventricular tachycardia ablation. Heart Rhythm O2 2021; 2:280-289. [PMID: 34337579 PMCID: PMC8322930 DOI: 10.1016/j.hroo.2021.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The presence of dynamic substrate changes may facilitate functional block and reentry in ventricular tachycardia (VT). OBJECTIVE We aimed to study dynamic ventricular repolarization changes in critical regions of the VT circuit during sensed single extrastimulus pacing known as the Sense Protocol (SP). METHODS Twenty patients (aged 67 ± 9 years, 17 male) underwent VT ablation. A bipolar voltage map was obtained during sinus rhythm (SR) and right ventricular SP pacing at 20 ms above ventricular effective refractory period. Ventricular repolarization maps were constructed. Ventricular repolarization time (RT) was calculated from unipolar electrogram T waves, using the Wyatt method, as the dV/dtmax of the unipolar T wave. Entrainment or pace mapping confirmed critical sites for ablation. RESULTS The median global repolarization range (max-min RT per patient) was 166 ms (interquartile range [IQR] 143-181 ms) during SR mapping vs 208 ms (IQR 182-234) during SP mapping (P = .0003 vs intrinsic rhythm). Regions of late potentials (LP) had a longer RT during SP mapping compared to regions without LP (mean 394 ± 40 ms vs 342 ± 25 ms, P < .001). In paired regions of normal myocardium there was no significant spatial dispersion of repolarization (SDR)/10 mm2 during SP mapping vs SR mapping (SDR 11 ± 6 ms vs 10 ± 6 ms, P = .54). SDR/10 mm2 was greater in critical areas of the VT circuit during SP mapping 63 ± 29 ms vs SR mapping 16 ± 9 ms (P < .001). CONCLUSION Ventricular repolarization is prolonged in regions of LP and increases dynamically, resulting in dynamic SDR in critical areas of the VT circuit. These dynamic substrate changes may be an important factor that facilitates VT circuits.
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Affiliation(s)
- Neil T. Srinivasan
- Department of Cardiac Electrophysiology, The Essex Cardiothoracic Centre, Basildon, Essex, United Kingdom
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
- Institute of Cardiovascular Science, University College London, London, United Kingdom
- Circulatory Health Research Group, Medical Technology Research Centre, School of Medicine, Anglia Ruskin University, Essex, United Kingdom
| | - Jason Garcia
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Richard J. Schilling
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Syed Ahsan
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Ross J. Hunter
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Martin Lowe
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Anthony W. Chow
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
| | - Pier D. Lambiase
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew’s Hospital, London, United Kingdom
- Institute of Cardiovascular Science, University College London, London, United Kingdom
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10
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Piktel JS, Suen Y, Kouk S, Maleski D, Pawlowski G, Laurita KR, Wilson LD. Effect of Amiodarone and Hypothermia on Arrhythmia Substrates During Resuscitation. J Am Heart Assoc 2021; 10:e016676. [PMID: 33938226 PMCID: PMC8200710 DOI: 10.1161/jaha.120.016676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Background Amiodarone is administered during resuscitation, but its antiarrhythmic effects during targeted temperature management are unknown. The purpose of this study was to determine the effect of both therapeutic hypothermia and amiodarone on arrhythmia substrates during resuscitation from cardiac arrest. Methods and Results We utilized 2 complementary models: (1) In vitro no‐flow global ischemia canine left ventricular transmural wedge preparation. Wedges at different temperatures (36°C or 32°C) were given 5 µmol/L amiodarone (36‐Amio or 32‐Amio, each n=8) and subsequently underwent ischemia and reperfusion. Results were compared with previous controls. Optical mapping was used to measure action potential duration, dispersion of repolarization (DOR), and conduction velocity (CV). (2) In vivo pig model of resuscitation. Pigs (control or targeted temperature management, 32–34°C) underwent ischemic cardiac arrest and were administered amiodarone (or not) after 8 minutes of ventricular fibrillation. In vitro: therapeutic hypothermia but not amiodarone prolonged action potential duration. During ischemia, DOR increased in the 32‐Amio group versus 32‐Alone (84±7 ms versus 40±7 ms, P<0.05) while CV slowed in the 32‐Amio group. Amiodarone did not affect CV, DOR, or action potential duration during ischemia at 36°C. Conduction block was only observed at 36°C (5/8 36‐Amio versus 6/7 36‐Alone, 0/8 32‐Amio, versus 0/7 32‐Alone). In vivo: QTc decreased upon reperfusion from ischemia that was ameliorated by targeted temperature management. Amiodarone did not worsen DOR or CV. Amiodarone suppressed rearrest caused by ventricular fibrillation (7/8 without amiodarone, 2/7 with amiodarone, P=0.041), but not pulseless electrical activity (2/8 without amiodarone, 5/7 with amiodarone, P=0.13). Conclusions Although amiodarone abolishes a beneficial effect of therapeutic hypothermia on ischemia‐induced DOR and CV, it did not worsen susceptibility to ventricular tachycardia/ventricular fibrillation during resuscitation.
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Affiliation(s)
- Joseph S Piktel
- Department of Emergency Medicine and The Heart and Vascular Research Center MetroHealth Campus Case Western Reserve University Cleveland OH
| | - Yi Suen
- Department of Emergency Medicine and The Heart and Vascular Research Center MetroHealth Campus Case Western Reserve University Cleveland OH
| | - Shalen Kouk
- Department of Emergency Medicine and The Heart and Vascular Research Center MetroHealth Campus Case Western Reserve University Cleveland OH
| | - Danielle Maleski
- Department of Emergency Medicine and The Heart and Vascular Research Center MetroHealth Campus Case Western Reserve University Cleveland OH
| | - Gary Pawlowski
- Department of Emergency Medicine and The Heart and Vascular Research Center MetroHealth Campus Case Western Reserve University Cleveland OH
| | - Kenneth R Laurita
- Department of Emergency Medicine and The Heart and Vascular Research Center MetroHealth Campus Case Western Reserve University Cleveland OH
| | - Lance D Wilson
- Department of Emergency Medicine and The Heart and Vascular Research Center MetroHealth Campus Case Western Reserve University Cleveland OH
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11
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Dietrichs ES, Selli AL, Kondratiev T, McGlynn K, Smith G, Tveita T. Resistance to ventricular fibrillation predicted by the QRS/QTc - Ratio in an intact rat model of hypothermia/rewarming. Cryobiology 2021; 98:33-38. [PMID: 33412156 DOI: 10.1016/j.cryobiol.2021.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/29/2020] [Accepted: 01/01/2021] [Indexed: 01/19/2023]
Abstract
Accidental hypothermia is associated with increased risk for arrhythmias. QRS/QTc is proposed as an ECG-marker, where decreasing values predict hypothermia-induced ventricular arrhythmias. If reliable it should also predict nonappearance of arrhythmias, observed in species like rat that regularly tolerate prolonged hypothermia. A rat model designed for studying cardiovascular function during cooling, hypothermia and subsequent rewarming was chosen due to species-dependent resistance to ventricular arrhythmias. ECG was recorded throughout the protocol. No ventricular arrhythmias occurred during experiments. QRS/QTc increased throughout the cooling period and remained above normothermic baseline until rewarmed. Different from the high incidence of hypothermia-induced ventricular arrhythmias in accidental hypothermia patients, where QRS/QTc ratio is decreased in moderate hypothermia; hypothermia and rewarming of rats is not associated with increased risk for ventricular fibrillation. This resistance to lethal hypothermia-induced arrhythmias was predicted by QRS/QTc.
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Affiliation(s)
- Erik Sveberg Dietrichs
- Experimental and Clinical Pharmacology, Department of Medical Biology, UiT, The Arctic University of Norway, 9037, Tromsø, Norway; Division of Diagnostic Services, University Hospital of Northern Norway, Tromsø, Norway.
| | - Anders Lund Selli
- Experimental and Clinical Pharmacology, Department of Medical Biology, UiT, The Arctic University of Norway, 9037, Tromsø, Norway
| | - Timofei Kondratiev
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, 9037, Tromsø, Norway
| | - Karen McGlynn
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, UK
| | - Godfrey Smith
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, UK
| | - Torkjel Tveita
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, UiT, The Arctic University of Norway, 9037, Tromsø, Norway; Division of Surgical Medicine and Intensive Care, University Hospital of North Norway, 9038, Tromsø, Norway
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12
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Xie LH, Gwathmey JK, Zhao Z. Cardiac adaptation and cardioprotection against arrhythmias and ischemia-reperfusion injury in mammalian hibernators. Pflugers Arch 2021; 473:407-416. [PMID: 33394082 DOI: 10.1007/s00424-020-02511-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/04/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022]
Abstract
Hibernation allows animals to enter an energy conserving state to survive severe drops in external temperatures and a shortage of food. It has been observed that the hearts of mammalian hibernators exhibit intrinsic protection against ischemia-reperfusion (I/R) injury and cardiac arrhythmias in the winter whether they are hibernating or not. However, the molecular and ionic mechanisms for cardioprotection in mammalian hibernators remain elusive. Recent studies in woodchucks (Marmota monax) have suggested that cardiac adaptation occurs at different levels and mediates an intrinsic cardioprotection prior to/in the winter. The molecular/cellular remodeling in the winter (with or without hibernation) includes (1) an upregulation of transcriptional factor, anti-apoptotic factor, nitric oxide synthase, protein kinase C-ε, and phosphatidylinositol-4,5-bisphosphate 3-kinase; (2) an upregulation of antioxidant enzymes (e.g. superoxide dismutase and catalase); (3) a reduction in the oxidation level of Ca2+/calmodulin-dependent protein kinase II (CaMKII); and (4) alterations in the expression and activity of multiple ion channels/transporters. Therefore, the cardioprotection against I/R injury in the winter is most likely mediated by enhancement in signaling pathways that are shared by preconditioning, reduced cell apoptosis, and increased detoxification of reactive oxygen species (ROS). The resistance to cardiac arrhythmias and sudden cardiac death in the winter is closely associated with an upregulation of the antioxidant catalase and a downregulation of CaMKII activation. This remodeling of the heart is associated with a reduction in the incidence of afterdepolarizations and triggered activities. In this short review article, we will discuss the seasonal changes in gene and protein expression profiles as well as alterations in the function of key proteins that are associated with the occurrence of cardioprotection against myocardial damage from ischemic events and fatal arrhythmias in a mammalian hibernator. Understanding the intrinsic cardiac adaptive mechanisms that confer cardioprotection in hibernators may offer new strategies to protect non-hibernating animals, especially humans, from I/R injury and ischemia-induced fatal cardiac arrhythmias.
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Affiliation(s)
- Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA.
| | - Judith K Gwathmey
- Department of Cell Biology and Molecular Medicine, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Zhenghang Zhao
- Department of Pharmacology, School of Medicine, Xi'an Jiaotong University, Xi'an, 710061, China
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13
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Wisløff-Aase K, Kerans V, Haugaa K, Halvorsen PS, Skulstad H, Espinoza A. Changes in left ventricular electromechanical relations during targeted hypothermia. Intensive Care Med Exp 2020; 8:76. [PMID: 33315166 PMCID: PMC7736464 DOI: 10.1186/s40635-020-00363-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/02/2020] [Indexed: 12/04/2022] Open
Abstract
Background Targeted hypothermia, as used after cardiac arrest, increases electrical and mechanical systolic duration. Differences in duration of electrical and mechanical systole are correlated to ventricular arrhythmias. The electromechanical window (EMW) becomes negative when the electrical systole outlasts the mechanical systole. Prolonged electrical systole corresponds to prolonged QT interval, and is associated with increased dispersion of repolarization and mechanical dispersion. These three factors predispose for arrhythmias. The electromechanical relations during targeted hypothermia are unknown. We wanted to explore the electromechanical relations during hypothermia at 33 °C. We hypothesized that targeted hypothermia would increase electrical and mechanical systolic duration without more profound EMW negativity, nor an increase in dispersion of repolarization and mechanical dispersion. Methods In a porcine model (n = 14), we registered electrocardiogram (ECG) and echocardiographic recordings during 38 °C and 33 °C, at spontaneous and atrial paced heart rate 100 beats/min. EMW was calculated by subtracting electrical systole; QT interval, from the corresponding mechanical systole; QRS onset to aortic valve closure. Dispersion of repolarization was measured as time from peak to end of the ECG T wave. Mechanical dispersion was calculated by strain echocardiography as standard deviation of time to peak strain. Results Electrical systole increased during hypothermia at spontaneous heart rate (p < 0.001) and heart rate 100 beats/min (p = 0.005). Mechanical systolic duration was prolonged and outlasted electrical systole independently of heart rate (p < 0.001). EMW changed from negative to positive value (− 20 ± 19 to 27 ± 34 ms, p = 0.001). The positivity was even more pronounced at heart rate 100 beats/min (− 25 ± 26 to 41 ± 18 ms, p < 0.001). Dispersion of repolarization decreased (p = 0.027 and p = 0.003), while mechanical dispersion did not differ (p = 0.078 and p = 0.297). Conclusion Targeted hypothermia increased electrical and mechanical systolic duration, the electromechanical window became positive, dispersion of repolarization was slightly reduced and mechanical dispersion was unchanged. These alterations may have clinical importance. Further clinical studies are required to clarify whether corresponding electromechanical alterations are accommodating in humans.
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Affiliation(s)
- Kristin Wisløff-Aase
- Department of Anaesthesiology, Oslo University Hospital - Rikshospitalet, Nydalen, PO Box 4950, 0424, Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Viesturs Kerans
- Department of Anaesthesiology, Oslo University Hospital - Rikshospitalet, Nydalen, PO Box 4950, 0424, Oslo, Norway
| | - Kristina Haugaa
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Oslo, Norway
| | - Per Steinar Halvorsen
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,The Intervention Centre, Oslo University Hospital, Oslo, Norway
| | - Helge Skulstad
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Oslo, Norway.,The Intervention Centre, Oslo University Hospital, Oslo, Norway
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14
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Bazmi M, Escobar AL. Excitation-Contraction Coupling in the Goldfish ( Carassius auratus) Intact Heart. Front Physiol 2020; 11:1103. [PMID: 33041845 PMCID: PMC7518121 DOI: 10.3389/fphys.2020.01103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/10/2020] [Indexed: 12/17/2022] Open
Abstract
Cardiac physiology of fish models is an emerging field given the ease of genome editing and the development of transgenic models. Several studies have described the cardiac properties of zebrafish (Denio rerio). The goldfish (Carassius auratus) belongs to the same family as the zebrafish and has emerged as an alternative model with which to study cardiac function. Here, we propose to acutely study electrophysiological and systolic Ca2+ signaling in intact goldfish hearts. We assessed the Ca2+ dynamics and the electrophysiological cardiac function of goldfish, zebrafish, and mice models, using pulsed local field fluorescence microscopy, intracellular microelectrodes, and flash photolysis in perfused hearts. We observed goldfish ventricular action potentials (APs) and Ca2+ transients to be significantly longer when compared to the zebrafish. The action potential half duration at 50% (APD50) of goldfish was 370.38 ± 8.8 ms long, and in the zebrafish they were observed to be only 83.9 ± 9.4 ms. Additionally, the half duration of the Ca2+ transients was also longer for goldfish (402.1 ± 4.4 ms) compared to the zebrafish (99.1 ± 2.7 ms). Also, blocking of the L-type Ca2+ channels with nifedipine revealed this current has a major role in defining the amplitude and the duration of goldfish Ca2+ transients. Interestingly, nifedipine flash photolysis experiments in the intact heart identified whether or not the decrease in the amplitude of Ca2+ transients was due to shorter APs. Moreover, an increase in temperature and heart rate had a strong shortening effect on the AP and Ca2+ transients of goldfish hearts. Furthermore, ryanodine (Ry) and thapsigargin (Tg) significantly reduced the amplitude of the Ca2+ transients, induced a prolongation in the APs, and altogether exhibited the degree to which the Ca2+ release from the sarcoplasmic reticulum contributed to the Ca2+ transients. We conclude that the electrophysiological properties and Ca2+ signaling in intact goldfish hearts strongly resembles the endocardial layer of larger mammals.
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Affiliation(s)
- Maedeh Bazmi
- Quantitative Systems Biology Program, School of Natural Sciences, University of California, Merced, Merced, CA, United States
| | - Ariel L Escobar
- Department of Bioengineering, School of Engineering, University of California, Merced, Merced, CA, United States
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15
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Dietrichs ES, Tveita T, Smith G. Hypothermia and cardiac electrophysiology: a systematic review of clinical and experimental data. Cardiovasc Res 2020; 115:501-509. [PMID: 30544147 DOI: 10.1093/cvr/cvy305] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/05/2018] [Accepted: 12/11/2018] [Indexed: 12/17/2022] Open
Abstract
Moderate therapeutic hypothermia procedures are used in post-cardiac arrest care, while in surgical procedures, lower core temperatures are often utilized to provide cerebral protection. Involuntary reduction of core body temperature takes place in accidental hypothermia and ventricular arrhythmias are recognized as a principal cause for a high mortality rate in these patients. We assessed both clinical and experimental literature through a systematic literature search in the PubMed database, to review the effect of hypothermia on cardiac electrophysiology. From included studies, there is common experimental and clinical evidence that progressive cooling will induce changes in cardiac electrophysiology. The QT interval is prolonged and appears more sensitive to decreases in temperature than the QRS interval. Severe hypothermia is associated with more pronounced changes, some of which are proarrhythmic. This is supported clinically where severe accidental hypothermia is commonly associated with ventricular fibrillation or asystole. J-waves in human electrocardiogram recordings are regularly but not always observed in hypothermia. Its relation to ventricular repolarization and arrhythmias is not obvious. Little clinical data exist on efficacy of anti-arrhythmic drugs in hypothermia, while experimental data show the potential of some agents, such as the class III antiarrhythmic bretylium. It is apparent that QT-prolonging drugs should be avoided.
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Affiliation(s)
- Erik Sveberg Dietrichs
- Department of Medical Biology, Experimental and Clinical Pharmacology Research Group, UiT, The Arctic University of Norway, Tromsø, Norway.,Division of Diagnostic Services, Department of Clinical Pharmacology, University Hospital of North Norway, Tromsø, Norway
| | - Torkjel Tveita
- Department of Clinical Medicine, Anesthesia and Critical Care Research Group, UiT, The Arctic University of Norway, Tromsø, Norway.,Division of Surgical Medicine and Intensive Care, University Hospital of North Norway, Tromsø, Norway
| | - Godfrey Smith
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
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16
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Jančauskaitė D, Samalavičius R, Glaveckaitė S, Semėnienė P, Šerpytis P. Electrocardiographic changes during therapeutic hypothermia: observational data from a single centre. Acta Med Litu 2020; 26:159-166. [PMID: 32015670 DOI: 10.6001/actamedica.v26i3.4145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Background Therapeutic hypothermia is recommended to reduce the risk of hypoxic brain damage and improve short-term survival after cardiac arrest. It also temporarily affects the cardiac conduction system. The aim of this study was to evaluate electrocardiographic changes during therapeutic hypothermia and their impact on the outcome. Materials and methods This retrospective analysis involved 26 patients who underwent therapeutic hypothermia after cardiac arrest in Vilnius University Hospital Santaros Klinikos from 2011 to 2015. Results During cooling, a significant reduction in the heart rate (p = 0.013), shortening of QRS complex duration (p = 0.041), and prolongation of the QTc interval (p < 0.001) were observed. During the cooling period, five patients had subtle Osborn waves, which disappeared after rewarming. The association between electrocardiographic changes during cooling and unfavourable neurological outcome or in-hospital mortality was non-significant. Conclusions Therapeutic hypothermia after cardiac arrest causes reversible electrocardiographic changes that do not increase the risk of in-hospital mortality or unfavourable neurological outcomes.
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Affiliation(s)
| | - Robertas Samalavičius
- Centre of Anaesthesia, Intensive Care and Pain Management, Vilnius University Hospital Santaros klinikos, Vilnius, Lithuania
| | - Sigita Glaveckaitė
- Clinic of Cardiovascular Diseases, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.,Centre of Cardiology and Angiology, Vilnius University Hospital Santaros klinikos, Vilnius, Lithuania
| | - Palmyra Semėnienė
- Clinic of Cardiovascular Diseases, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.,Centre of Cardiology and Angiology, Vilnius University Hospital Santaros klinikos, Vilnius, Lithuania
| | - Pranas Šerpytis
- Clinic of Cardiovascular Diseases, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.,Centre of Cardiology and Angiology, Vilnius University Hospital Santaros klinikos, Vilnius, Lithuania.,Emergency Medicine Centre, Vilnius University Hospital Santaros klinikos, Vilnius, Lithuania
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17
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Yuxiang L, Fujiu K. Frozen Heart and Arrhythmia. Int Heart J 2019; 60:1019-1021. [PMID: 31564707 DOI: 10.1536/ihj.19-407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Liu Yuxiang
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo
| | - Katsuhito Fujiu
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo.,Department of Advanced Cardiology, Graduate School of Medicine, The University of Tokyo
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18
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Saitoh O, Watanabe J, Oikawa A, Sugai A, Furushima H, Chinushi M. Therapy-Resistant Ventricular Arrhythmias Developed More Often in Advanced Than in Therapeutic Mild Hypothermic Condition. Int Heart J 2019; 60:1161-1167. [PMID: 31484866 DOI: 10.1536/ihj.18-711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Therapy-resistant ventricular arrhythmias can occur during accidental advanced hypothermic conditions. On the other hand, hypothermic therapy using mild cooling has been successfully accomplished with infrequent ventricular arrhythmia events.To further clarify the therapeutic-resistant arrhythmogenic substrate which develops in hypothermic conditions, an experimental study was performed using a perfusion wedge preparation model of porcine ventricle, and electrophysiological characteristics, inducibility of ventricular arrhythmias, and effects of therapeutic interventions were assessed at 3 target temperatures (37, 32 and 28°C).As the myocardial temperature decreased, myocardial contractions and the number of spontaneous beats deceased. Depolarization (QRS width, stimulus-QRS interval) and repolarization (QT interval, ERP) parameters progressively increased, and dispersion of the ventricular repolarization increased. At 28°C, VF tended to be inducible more frequently (1/11 at 37°C, 1/11 at 32°C, and 5/11 hearts at 28°C), and some VFs at 28°C required greater defibrillation energy to resume basic rhythm.An advanced but not a mild hypothermic condition had an enhanced arrhythmogenic potential in our model. In the advanced hypothermic condition, VF with relatively prolonged F-F intervals and a greater defibrillation energy were occasionally inducible based on the arrhythmogenic substrate characterized as slowed conduction and prolonged repolarization of the ventricle.
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Affiliation(s)
- Osamu Saitoh
- Cardiovascular Research of Graduate School of Health Sciences, Niigata University School of Medicine
| | - Junya Watanabe
- Cardiovascular Research of Graduate School of Health Sciences, Niigata University School of Medicine
| | - Ayaka Oikawa
- Cardiovascular Research of Graduate School of Health Sciences, Niigata University School of Medicine
| | - Ayari Sugai
- Cardiovascular Research of Graduate School of Health Sciences, Niigata University School of Medicine
| | - Hiroshi Furushima
- Cardiovascular Research of Graduate School of Health Sciences, Niigata University School of Medicine
| | - Masaomi Chinushi
- Cardiovascular Research of Graduate School of Health Sciences, Niigata University School of Medicine
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19
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Lions S, Dragu R, Carsenty Y, Zukermann R, Aronson D. Determinants of cardiac repolarization and risk for ventricular arrhythmias during mild therapeutic hypothermia. J Crit Care 2019; 46:151-156. [PMID: 29929706 DOI: 10.1016/j.jcrc.2018.03.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 03/06/2018] [Accepted: 03/06/2018] [Indexed: 11/20/2022]
Abstract
PURPOSE We aimed to investigate the factors that modulate the extent of QTc prolongation and potential arrhythmogenic consequences during mild therapeutic hypothermia (MTH). METHODS We studied 205 patients after out-of-hospital cardiac arrest (131 underwent MTH). QTc was measured at baseline, 3h, 6h, 12h, 24h (end of hypothermia), 48h and 72h, and ventricular arrhythmias quantified. RESULTS During MTH, the QTc interval increased progressively peaking at 12h (mean increase 42ms, 95% CI 30-55). There was a strong gender effect (P<0.001) and a significant gender-by-MTH interaction (P=0.004). At 12h, the QTc interval was markedly longer in women as compared with men (mean difference 50ms [95% CI 27-73]. Anoxic brain injury (P=0.002) was also positively associated with QTc prolongation. The risk for ventricular arrhythmic events was not higher with MTH compared with no hypothermia (incidence rate ratio 0.57, 95% CI 0.32-1.02, P=0.06). However, typical cases of Torsade de pointes occurred in association with AV block and LQT2. CONCLUSION QTc prolongation during MTH is strongly affected by female gender and moderately by concomitant anoxic brain injury. Although the overall risk for ventricular arrhythmias is not greater with MTH, Torsade de pointes may develop when other contributing factors coexist.
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Affiliation(s)
- Svetlana Lions
- Department of Cardiology, Rambam Medical Center, Haifa, Israel; Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Israel
| | - Robert Dragu
- Department of Cardiology, Rambam Medical Center, Haifa, Israel; Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Israel
| | - Yoav Carsenty
- Department of Cardiology, Rambam Medical Center, Haifa, Israel; Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Israel
| | - Robert Zukermann
- Department of Cardiology, Rambam Medical Center, Haifa, Israel; Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Israel
| | - Doron Aronson
- Department of Cardiology, Rambam Medical Center, Haifa, Israel; Ruth & Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Israel.
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20
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Manninger M, Alogna A, Zweiker D, Zirngast B, Reiter S, Herbst V, Maechler H, Pieske BM, Heinzel FR, Brussee H, Post H, Scherr D. Mild hypothermia (33°C) increases the inducibility of atrial fibrillation: An
in vivo
large animal model study. Pacing Clin Electrophysiol 2018; 41:720-726. [DOI: 10.1111/pace.13351] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 03/05/2018] [Accepted: 03/30/2018] [Indexed: 11/28/2022]
Affiliation(s)
| | - Alessio Alogna
- Department of Internal Medicine and Cardiology, Campus Virchow KlinikumCharité University Medicine Berlin Berlin Germany
- Berlin Institute of Health (BIH) Berlin Germany
| | - David Zweiker
- Department of CardiologyMedical University of Graz Graz Austria
| | - Birgit Zirngast
- Department of Cardiothoracic SurgeryMedical University of Graz Graz Austria
| | - Stefan Reiter
- Department of CardiologyMedical University of Graz Graz Austria
| | - Viktoria Herbst
- Department of CardiologyMedical University of Graz Graz Austria
| | - Heinrich Maechler
- Department of Cardiothoracic SurgeryMedical University of Graz Graz Austria
| | - Burkert M. Pieske
- Department of Internal Medicine and Cardiology, Campus Virchow KlinikumCharité University Medicine Berlin Berlin Germany
| | - Frank R. Heinzel
- Department of Internal Medicine and Cardiology, Campus Virchow KlinikumCharité University Medicine Berlin Berlin Germany
| | - Helmut Brussee
- Department of CardiologyMedical University of Graz Graz Austria
| | - Heiner Post
- Department of Internal Medicine and Cardiology, Campus Virchow KlinikumCharité University Medicine Berlin Berlin Germany
| | - Daniel Scherr
- Department of CardiologyMedical University of Graz Graz Austria
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21
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Fukaya H, Piktel JS, Wan X, Plummer BN, Laurita KR, Wilson LD. Arrhythmogenic Delayed Afterdepolarizations Are Promoted by Severe Hypothermia But Not Therapeutic Hypothermia. Circ J 2018; 82:62-70. [DOI: 10.1253/circj.cj-17-0145] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hidehira Fukaya
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University
- Department of Cardiovascular Medicine, Kitasato University School of Medicine
| | - Joseph S. Piktel
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University
- Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University
| | - Xiaoping Wan
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University
| | - Bradley N. Plummer
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University
| | - Kenneth R. Laurita
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University
| | - Lance D. Wilson
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University
- Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University
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22
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Piktel JS, Cheng A, McCauley M, Dale Z, Nassal M, Maleski D, Pawlowski G, Laurita KR, Wilson LD. Hypothermia Modulates Arrhythmia Substrates During Different Phases of Resuscitation From Ischemic Cardiac Arrest. J Am Heart Assoc 2017; 6:JAHA.117.006472. [PMID: 29150491 PMCID: PMC5721747 DOI: 10.1161/jaha.117.006472] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background We designed an innovative porcine model of ischemia‐induced arrest to determine dynamic arrhythmia substrates during focal infarct, global ischemia from ventricular tachycardia or fibrillation (VT/VF) and then reperfusion to determine the effect of therapeutic hypothermia (TH) on dynamic arrhythmia substrates and resuscitation outcomes. Methods and Results Anesthetized adult pigs underwent thoracotomy and regional plunge electrode placement in the left ventricle. Subjects were then maintained at either control (CT; 37°C, n=9) or TH (33°C, n=8). The left anterior descending artery (LAD) was occluded and ventricular fibrillation occurred spontaneously or was induced after 30 minutes. Advanced cardiac life support was started after 8 minutes, and LAD reperfusion occurred 60 minutes after occlusion. Incidences of VF/VT and survival were compared with ventricular ectopy, cardiac alternans, global dispersion of repolarization during LAD occlusion, and LAD reperfusion. There was no difference in incidence of VT/VF between groups during LAD occlusion (44% in CT versus 50% in TH; P=1s). During LAD occlusion, ectopy was increased in CT and suppressed in TH (33±11 ventricular ectopic beats/min versus 4±6 ventricular ectopic beats/min; P=0.009). Global dispersion of repolarization and cardiac alternans were similar between groups. During LAD reperfusion, TH doubled the incidence of cardiac alternans compared with CT, with a marked increase in VF/VT (100% in TH versus 17% in CT; P=0.004). Ectopy and global dispersion of repolarization were similar between groups during LAD reperfusion. Conclusions TH alters arrhythmia substrates in a porcine translational model of resuscitation from ischemic cardiac arrest during the complex phases of resuscitation. TH worsens cardiac alternans, which was associated with an increase in spontaneous VT/VF during reperfusion.
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Affiliation(s)
- Joseph S Piktel
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Aurelia Cheng
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Matthew McCauley
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Zack Dale
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Michelle Nassal
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Danielle Maleski
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Gary Pawlowski
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Kenneth R Laurita
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Lance D Wilson
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
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Kienast R, Handler M, Stöger M, Baumgarten D, Hanser F, Baumgartner C. Modeling hypothermia induced effects for the heterogeneous ventricular tissue from cellular level to the impact on the ECG. PLoS One 2017; 12:e0182979. [PMID: 28813535 PMCID: PMC5558962 DOI: 10.1371/journal.pone.0182979] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 07/27/2017] [Indexed: 11/18/2022] Open
Abstract
Hypothermia has a profound impact on the electrophysiological mechanisms of the heart. Experimental investigations provide a better understanding of electrophysiological alterations associated with cooling. However, there is a lack of computer models suitable for simulating the effects of hypothermia in cardio-electrophysiology. In this work, we propose a model that describes the cooling-induced electrophysiological alterations in ventricular tissue in a temperature range from 27°C to 37°C. To model the electrophysiological conditions in a 3D left ventricular tissue block it was essential to consider the following anatomical and physiological parameters in the model: the different cell types (endocardial, M, epicardial), the heterogeneous conductivities in longitudinal, transversal and transmural direction depending on the prevailing temperature, the distinct fiber orientations and the transmural repolarization sequences. Cooling-induced alterations on the morphology of the action potential (AP) of single myocardial cells thereby are described by an extension of the selected Bueno-Orovio model for human ventricular tissue using Q10 temperature coefficients. To evaluate alterations on tissue level, the corresponding pseudo electrocardiogram (pECG) was calculated. Simulations show that cooling-induced AP and pECG-related parameters, i.e. AP duration, morphology of the notch of epicardial AP, maximum AP upstroke velocity, AP rise time, QT interval, QRS duration and J wave formation are in good accordance with literature and our experimental data. The proposed model enables us to further enhance our knowledge of cooling-induced electrophysiological alterations from cellular to tissue level in the heart and may help to better understand electrophysiological mechanisms, e.g. in arrhythmias, during hypothermia.
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Affiliation(s)
- Roland Kienast
- Institute of Electrical and Biomedical Engineering, UMIT–University for Health Sciences, Medical Informatics and Technology, Hall, Tyrol, Austria
- * E-mail:
| | - Michael Handler
- Institute of Electrical and Biomedical Engineering, UMIT–University for Health Sciences, Medical Informatics and Technology, Hall, Tyrol, Austria
| | - Markus Stöger
- Institute of Electrical and Biomedical Engineering, UMIT–University for Health Sciences, Medical Informatics and Technology, Hall, Tyrol, Austria
| | - Daniel Baumgarten
- Institute of Electrical and Biomedical Engineering, UMIT–University for Health Sciences, Medical Informatics and Technology, Hall, Tyrol, Austria
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, Germany
| | - Friedrich Hanser
- Institute of Electrical and Biomedical Engineering, UMIT–University for Health Sciences, Medical Informatics and Technology, Hall, Tyrol, Austria
| | - Christian Baumgartner
- Institute of Electrical and Biomedical Engineering, UMIT–University for Health Sciences, Medical Informatics and Technology, Hall, Tyrol, Austria
- Institute of Health Care Engineering with European Testing Center of Medical Devices, Graz University of Technology, Graz, Austria
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24
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von Ulmenstein S, Storm C, Breuer TGK, Lask S, Attanasio P, Mügge A, Wutzler A. Hypothermia induced alteration of repolarization - impact on acute and long-term outcome: a prospective cohort study. Scand J Trauma Resusc Emerg Med 2017; 25:68. [PMID: 28693536 PMCID: PMC5504768 DOI: 10.1186/s13049-017-0417-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 07/05/2017] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND The effects of target temperature management (TTM) on the heart aren't thoroughly studied yet. Several studies showed the prolongation of various ECG parameters including Tpeak-Tend-time under TTM. Our study's goal is to evaluate the acute and long-term outcome of these prolongations. METHODS In this study we included patients with successful resuscitation after cardiac arrest who were admitted to the Charité Virchow Klinikum Berlin or the Heart and Vascular Centre of the Ruhr University Bochum between February 2006 and July 2013 (Berlin) or May 2014 to November 2015 (Bochum). For analysis, one ECG during TTM was recorded after reaching the target temperature (33-34 °C) or in the first 6 h of TTM. If possible, another ECG was taken after TTM. The patients were being followed until February 2016. Primary endpoint was ventricular arrhythmia during TTM, secondary endpoints were death and hospitalization due to cardiovascular diseases during follow-up. RESULTS One hundred fifty-eight patients were successfully resuscitated in the study period of which 95 patients had usable data (e.g. ECGs without artifacts). During TTM significant changes for different parameters of ventricular de- and repolarization were noted: QRS (103.2 ± 23.7 vs. 95.3 ± 18.1; p = 0.003),QT (405.8 ± 76.4 vs. 373.8 ± 75.0; p = 0.01), QTc (474.9 ± 59.7 vs. 431.0 ± 56.8; p < 0.001), JT (302.8 ± 69.4 vs. 278.5 ± 75.2; p = 0.043), JTc (354.3 ± 60.2 vs. 318.7 ± 59.1; p = 0.001). 13.7% of the patients had ventricular arrhythmias during TTM, however these patients showed no difference regarding their ECG parameters in comparison to those were no ventricular arrhythmias occurred. We were able to follow 69 Patients over an average period of 35 ± 31 months. The 14 (21.5%) patients who died during the follow-up had significant prolongations of the TpTe-time in the ECGs without TTM (103.9 ± 47.2 vs. 75.8 ± 28.6; p = 0.023). CONCLUSION Our results show a significant prolongation of ventricular repolarization during TH. However, there was no significant difference between the ECG parameters of those who developed a ventricular arrhythmia and those who did not. The temporary prolongation of the repolarization during TTM seems to be less important for the prognosis of the patient. Whereas the prolongation of the repolarization in the basal ECG is associated with a higher mortality in our study.
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Affiliation(s)
- Sophie von Ulmenstein
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - Christian Storm
- Department of Nephrology and Intensive Care Medicine, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Berlin, Germany
| | - Thomas G K Breuer
- Department of Internal Medicine of the Ruhr-University Bochum, St. Josef-Hospital, Bochum, Germany
| | - Sebastian Lask
- Heart and Vascular Center of the Ruhr-University Bochum, St. Josef-Hospital, Bochum, Germany
| | - Philipp Attanasio
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Andreas Mügge
- Heart and Vascular Center of the Ruhr-University Bochum, St. Josef-Hospital, Bochum, Germany
| | - Alexander Wutzler
- Department of Cardiology, Charité - Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany.,Heart and Vascular Center of the Ruhr-University Bochum, St. Josef-Hospital, Bochum, Germany
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25
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Nassal MMJ, Wan X, Dale Z, Deschênes I, Wilson LD, Piktel JS. Mild hypothermia preserves myocardial conduction during ischemia by maintaining gap junction intracellular communication and Na + channel function. Am J Physiol Heart Circ Physiol 2017; 312:H886-H895. [PMID: 28283549 DOI: 10.1152/ajpheart.00298.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 03/03/2017] [Accepted: 03/03/2017] [Indexed: 11/22/2022]
Abstract
Acute cardiac ischemia induces conduction velocity (CV) slowing and conduction block, promoting reentrant arrhythmias leading to sudden cardiac arrest. Previously, we found that mild hypothermia (MH; 32°C) attenuates ischemia-induced conduction block and CV slowing in a canine model of early global ischemia. Acute ischemia impairs cellular excitability and the gap junction (GJ) protein connexin (Cx)43. We hypothesized that MH prevented ischemia-induced conduction block and CV slowing by preserving GJ expression and localization. Canine left ventricular preparations at control (36°C) or MH (32°C) were subjected to no-flow prolonged (30 min) ischemia. Optical action potentials were recorded from the transmural left ventricular wall, and CV was measured throughout ischemia. Cx43 and Na+ channel (NaCh) remodeling was assessed using both confocal immunofluorescence (IF) and/or Western blot analysis. Cellular excitability was determined by microelectrode recordings of action potential upstroke velocity (dV/dtmax) and resting membrane potential (RMP). NaCh current was measured in isolated canine myocytes at 36 and 32°C. As expected, MH prevented conduction block and mitigated ischemia-induced CV slowing during 30 min of ischemia. MH maintained Cx43 at the intercalated disk (ID) and attenuated ischemia-induced Cx43 degradation by both IF and Western blot analysis. MH also preserved dV/dtmax and NaCh function without affecting RMP. No difference in NaCh expression was seen at the ID by IF or Western blot analysis. In conclusion, MH preserves myocardial conduction during prolonged ischemia by maintaining Cx43 expression at the ID and maintaining NaCh function. Hypothermic preservation of GJ coupling and NaCh may be novel antiarrhythmic strategies during resuscitation.NEW & NOTEWORTHY Therapeutic hypothermia is now a class I recommendation for resuscitation from cardiac arrest. This study determined that hypothermia preserves gap junction coupling as well as Na+ channel function during acute cardiac ischemia, attenuating conduction slowing and preventing conduction block, suggesting that induced hypothermia may be a novel antiarrhythmic strategy in resuscitation.
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Affiliation(s)
- Michelle M J Nassal
- The Heart and Vascular Research Center and Department of Physiology, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; and
| | - Xiaoping Wan
- The Heart and Vascular Research Center and Department of Physiology, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; and
| | - Zack Dale
- The Heart and Vascular Research Center and Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Isabelle Deschênes
- The Heart and Vascular Research Center and Department of Physiology, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; and
| | - Lance D Wilson
- The Heart and Vascular Research Center and Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Joseph S Piktel
- The Heart and Vascular Research Center and Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University School of Medicine, Cleveland, Ohio
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26
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Guerra F, Bonelli P, Flori M, Cipolletta L, Carbucicchio C, Izquierdo M, Kozluk E, Shivkumar K, Vaseghi M, Patani F, Cupido C, Pala S, Ruiz-Granell R, Ferrero A, Tondo C, Capucci A. Temporal Trends and Temperature-Related Incidence of Electrical Storm. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.116.004634. [DOI: 10.1161/circep.116.004634] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/27/2016] [Indexed: 01/28/2023]
Abstract
Background—
The occurrence of ventricular tachyarrhythmias seems to follow circadian, daily, and seasonal distributions. Our aim is to identify potential temporal patterns of electrical storm (ES), in which a cluster of ventricular tachycardias or ventricular fibrillation, negatively affects short- and long-term survival.
Methods and Results—
The TEMPEST study (Circannual Pattern and Temperature-Related Incidence of Electrical Storm) is a patient-level, pooled analysis of previously published data sets. Study selection criteria included diagnosis of ES, absence of acute coronary syndrome as the arrhythmic trigger, and ≥10 patients included. At the end of the selection and collection processes, 5 centers had the data set from their article pooled into the present registry. Temperature data and sunrise and sunset hours were retrieved from Weather Underground, the largest weather database available online. Total sample included 246 patients presenting with ES (221 men; age: 65±9 years). Each ES episode included a median of 7 ventricular tachycardia/ventricular fibrillation episodes. Fifty-nine percent of patients experienced ES during daytime hours (
P
<0.001). The prevalence of ES was significantly higher during workdays, with Saturdays and Sundays registering the lowest rates of ES (10.4% and 7.2%, respectively, versus 16.5% daily mean from Monday to Friday;
P
<0.001). ES occurrence was significantly associated with increased monthly temperature range when compared with the month before (
P
=0.003).
Conclusions—
ES incidence is not homogenous over time but seems to have a clustered pattern, with a higher incidence during daytime hours and working days. ES is associated with an increase in monthly temperature variation.
Clinical Trial Registration—
https://www.crd.york.ac.uk
. Unique identifier: CRD42013003744.
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Affiliation(s)
- Federico Guerra
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Paolo Bonelli
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Marco Flori
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Laura Cipolletta
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Corrado Carbucicchio
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Maite Izquierdo
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Edward Kozluk
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Kalyanam Shivkumar
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Marmar Vaseghi
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Francesca Patani
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Claudio Cupido
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Salvatore Pala
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Ricardo Ruiz-Granell
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Angel Ferrero
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Claudio Tondo
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
| | - Alessandro Capucci
- From the Cardiology and Arrhythmology Clinic, Marche Polytechnic University, University Hospital “Ospedali Riuniti”, Ancona (F.G., P.B., M.F., L.C., F.P., C. Cupido, A.C.); Cardiology Center Monzino IRCCS, Milan, Italy (C. Carbucicchio, S.P., C.T.); University Hospital Clinic of Valencia, Spain (M.I., R.R.-G., A.F.); Medical University of Warsaw, Poland (E.K.); and Cardiac Arrhythmia Center, University of California, Los Angeles (K.S., M.V.)
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27
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Corrected QT interval during therapeutic hypothermia in hypoxic ischaemic encephalopathy. ANALES DE PEDIATRÍA (ENGLISH EDITION) 2016. [DOI: 10.1016/j.anpede.2016.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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28
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Siddiqi SA, Ulahannan J, Storm R. T-Wave Alternans in a Hypothermic Patient Leading to Unstable Ventricular Tachycardia. JACC Clin Electrophysiol 2016; 2:640-641. [PMID: 29759587 DOI: 10.1016/j.jacep.2016.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 02/18/2016] [Indexed: 10/22/2022]
Affiliation(s)
- Saquib A Siddiqi
- Department of Internal Medicine, Geisinger Medical Center, Danville, Pennsylvania, USA.
| | - John Ulahannan
- Department of Cardiology, Geisinger Medical Center, Danville, Pennsylvania, USA
| | - Randle Storm
- Department of Cardiology, Geisinger Medical Center, Danville, Pennsylvania, USA
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29
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Arteyeva NV, Azarov JE. The Role of Transmural Repolarization Gradient in the Inversion of Cardiac Electric Field: Model Study of ECG in Hypothermia. Ann Noninvasive Electrocardiol 2016; 22. [PMID: 27018036 DOI: 10.1111/anec.12360] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 01/24/2016] [Accepted: 02/11/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The changes in ventricular repolarization gradients lead to significant alterations of the electrocardiographic body surface T waves up to the T wave inversion. However, the contribution of a specific gradient remains to be elucidated. The objective of the present investigation was to study the role of the transmural repolarization gradient in the inversion of the body surface T wave with a mathematical model of the hypothermia-induced changes of ventricular repolarization. METHODS By means of mathematical simulation, we set the hypothermic action potential duration (APD) distribution on the rabbit ventricular epicardium as it was previously experimentally documented. Then the parameters of the body surface potential distribution were tested with the introduction of different scenarios of the endocardial and epicardial APD behavior in hypothermia resulting in the unchanged, reversed or enlarged transmural repolarization gradient. RESULTS The reversal of epicardial repolarization gradients (apicobasal, anterior-posterior and interventricular) caused the inversion of the T waves regardless of the direction of the transmural repolarization gradient. However, the most realistic body surface potentials were obtained when the endocardial APDs were not changed under hypothermia while the epicardial APDs prolonged. This produced the reversed and increased transmural repolarization gradient in absolute magnitude. The body surface potentials simulated under the unchanged transmural gradient were reduced in comparison to those simulated under the reversed transmural gradient. CONCLUSIONS The simulations demonstrated that the transmural repolarization gradient did not play a crucial role in the cardiac electric field inversion under hypothermia, but its magnitude and direction contribute to the T wave amplitude.
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Affiliation(s)
- Natalia V Arteyeva
- Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia
| | - Jan E Azarov
- Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia.,Department of Physiology, Medical Institute of Syktyvkar State University, Syktyvkar, Russia.,Department of Cardiology, Lund University, Lund, Sweden
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[Corrected QT interval during therapeutic hypothermia in hypoxic ischaemic encephalopathy]. An Pediatr (Barc) 2016; 85:312-317. [PMID: 26896912 DOI: 10.1016/j.anpedi.2016.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/22/2015] [Accepted: 01/11/2016] [Indexed: 11/20/2022] Open
Abstract
INTRODUCTION Therapeutic hypothermia is the standard treatment for hypoxic ischaemic encephalopathy (HIE), despite not knowing all its effects and complications. Sinus bradycardia is one of the consequences of cooling that has been previously documented in the literature, but little is known about the cardiac electrical activity in these patients. OBJECTIVE To determine the corrected QT (QTc) interval in newborns treated with therapeutic hypothermia for HIE. MATERIAL AND METHODS A prospective observational study was conducted in all patients treated with hypothermia for HIE that were admitted to our Unit between November 2012 and October 2013. ECGs were performed during hypothermia (every 24h), during the re-warming period (at 34.5°C, 35.5°C, 36.5°C), and on the 7th day of life. RESULTS A total of 19 patients were included. A prolonged QTc was observed in all patients during hypothermia, and 84% (n=16) had prolonged QTc in all the ECGs during treatment. In 3 patients, one of the ECGs did not have a prolonged QTc. After re-warming, the QTc interval returned to normal in all patients. No statistically significant differences were seen when the degree of HIE (P=.192) or the use of inotropic support (P=.669) were considered. CONCLUSIONS Therapeutic hypothermia applied to asphyxiated newborns with HIE seems to induce a QTc prolongation that resolves when the patient regains physiological temperature.
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Kim CY, Bae MH, Kim NK, Yang YA, Kim KY, Lee JH, Eun JS, Cho Y. Case of Recurrent Ventricular Fibrillations with Osborn Wave Developed during Therapeutic Hypothermia. Korean Circ J 2015; 45:81-4. [PMID: 25653709 PMCID: PMC4310985 DOI: 10.4070/kcj.2015.45.1.81] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 07/10/2014] [Accepted: 07/14/2014] [Indexed: 01/09/2023] Open
Abstract
Therapeutic hypothermia (TH) has been used to protect neurological functions in cardiac arrest patient. Although Osborn wave is not pathognomonic of hypothermia, it is a well-known electrocardiogram finding of hypothermic patients. The cellular and ionic mechanisms of the Osborn wave have been suggested, and its relationship to tachyarrhythmias, such as ventricular tachycardia and ventricular fibrillation, is being explored. This case highlights the arrhythmogenic potential of Osborn wave and individual difference in response of TH.
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Affiliation(s)
- Chang-Yeon Kim
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Myung Hwan Bae
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Nam Kyun Kim
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Young Ae Yang
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Kyu Yeun Kim
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Jang Hoon Lee
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Jung Su Eun
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Yongkeun Cho
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
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Hsieh YC, Lin SF, Huang JL, Hung CY, Lin JC, Liao YC, Lo CP, Wang KY, Wu TJ. Moderate Hypothermia (33 °C) Decreases the Susceptibility to Pacing-Induced Ventricular Fibrillation Compared with Severe Hypothermia (30 °C) by Attenuating Spatially Discordant Alternans in Isolated Rabbit Hearts. ACTA CARDIOLOGICA SINICA 2014; 30:455-465. [PMID: 27122819 PMCID: PMC4834958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 01/20/2014] [Indexed: 06/05/2023]
Abstract
BACKGROUND Severe hypothermia (SH, 30 °C) increases the risk of pacing-induced ventricular fibrillation (PIVF) by enhancing spatially discordant alternans (SDA). Whether moderate hypothermia (MH, 33 °C), which is clinically used for therapeutic hypothermia, also facilitates SDA remains unclear. We hypothesized that MH attenuates SDA occurrence compared with that achieved by SH, and decreases the susceptibility of PIVF. METHODS Using an optical mapping system, action potential duration (APD)/conduction velocity restitutions and thresholds of APD alternans were determined by S1 pacing in Langendorff-perfused isolated rabbit hearts. In the MH group (n = 7), S1 pacing was performed at baseline (37 °C), after 5-min MH, and after 5-min rewarming (37 °C). In the SH group (n = 9), pacing was also performed at baseline (37 °C), after 5-min SH, and after 5-min rewarming (37 °C). The thresholds of APD alternans were defined as the longest S1 pacing cycle length at which APD alternans were detected. RESULTS Although the thresholds of APD alternans were not different between the MH (273 ± 46 ms) and the SH (300 ± 35 ms) (p = 0.281) groups, SDA threshold was shorter (at a faster heart rate) during MH (228 ± 33 ms) than that during SH (289 ± 42 ms) (p = 0.028). At APD alternans threshold, SH hearts showed more SDA than that during MH (SH: 7 hearts, MH: 2 hearts, p = 0.049). SDA could be induced in all 9 SH hearts (100%), while only 4 MH hearts (57%) had SDA (p = 0.029). The PIVF inducibility during SH (44 ± 53%) was higher than that during MH (0%) (p = 0.043). CONCLUSIONS Compared with SH, the MH group showed greater attenuation of SDA and decreased the susceptibility of PIVF. Therefore, MH is safer as a procedural guideline for use in clinical therapeutic hypothermia than SH. KEY WORDS Cardiac alternans; Conduction velocity; Hypothermia; Optical mapping.
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Affiliation(s)
- Yu-Cheng Hsieh
- Cardiovascular Center, Taichung Veterans General Hospital, Taichung, and Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei
- Department of Financial and Computational Mathematics, Providence University, Taichung, Taiwan
| | - Shien-Fong Lin
- Krannert Institute of Cardiology and the Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
- Institute of Biomedical Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Jin-Long Huang
- Cardiovascular Center, Taichung Veterans General Hospital, Taichung, and Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei
| | - Chen-Ying Hung
- Cardiovascular Center, Taichung Veterans General Hospital, Taichung, and Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei
| | - Jiunn-Cherng Lin
- Cardiovascular Center, Taichung Veterans General Hospital, Taichung, and Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei
| | - Ying-Chieh Liao
- Cardiovascular Center, Taichung Veterans General Hospital, Taichung, and Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei
| | - Chu-Pin Lo
- Department of Financial and Computational Mathematics, Providence University, Taichung, Taiwan
| | - Kuo-Yang Wang
- Cardiovascular Center, Taichung Veterans General Hospital, Taichung, and Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei
| | - Tsu-Juey Wu
- Cardiovascular Center, Taichung Veterans General Hospital, Taichung, and Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei
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Nordberg P, Ivert T, Dalén M, Forsberg S, Hedman A. Surviving two hours of ventricular fibrillation in accidental hypothermia. PREHOSP EMERG CARE 2014; 18:446-9. [PMID: 24670046 DOI: 10.3109/10903127.2014.891066] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Cardiac arrest as a consequence of deep accidental hypothermia is associated with high mortality. Standardized prehospital management as well as rewarming with extracorporeal circulation (ECC) are important factors to improve survival. The objective of this case report is to illustrate the importance of effective cardiopulmonary resuscitation (CPR) and ECC in a cardiac arrest following deep accidental hypothermia. CASE REPORT A 42-year-old man was found unresponsive to external stimuli and pulseless at an outdoor temperature of 1°C. CPR was started at the scene by laypersons, and the emergency medical services (EMS) arrived 5 minutes after the emergency call. Resuscitation according to International Liaison Committee on Resuscitation (ILCOR) guidelines was initiated by EMS. The first recorded rhythm was ventricular fibrillation (VF), which persisted, despite repeated defibrillation. The patient showed signs of severe hypothermia and, during ongoing CPR, was transported to hospital where on arrival the patient's rectal temperature was measured at 22°C. Resuscitation measures were continued and warming was started at the emergency room. Due to persistent VF and deep hypothermia, the patient was transferred to a cardiothoracic surgical unit for rewarming with ECC. At commencement of ECC, CPR had been going for approximately 130 minutes and a total of 38 defibrillations had been made. During this time interval the patients was pulseless. At a core temperature of 30°C, one defibrillation restored sinus rhythm and subsequently stable circulation was achieved. The patient received a further 24 hours of hypothermia treatment at 32-34°C. He was discharged to rehabilitation facilities after 3 weeks of hospital care. Three months after the cardiac arrest the patient was fully recovered, was back to work, and had resumed normal activities. CONCLUSIONS We demonstrate a case of cardiac arrest due to deep accidental hypothermia that stresses the importance of effective CPR and early-stage consideration of the use of ECC for safe and effective rewarming.
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Filippi S, Gizzi A, Cherubini C, Luther S, Fenton FH. Mechanistic insights into hypothermic ventricular fibrillation: the role of temperature and tissue size. Europace 2014; 16:424-34. [PMID: 24569897 PMCID: PMC3934849 DOI: 10.1093/europace/euu031] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 01/27/2014] [Indexed: 12/26/2022] Open
Abstract
AIMS Hypothermia is well known to be pro-arrhythmic, yet it has beneficial effects as a resuscitation therapy and valuable during intracardiac surgeries. Therefore, we aim to study the mechanisms that induce fibrillation during hypothermia. A better understanding of the complex spatiotemporal dynamics of heart tissue as a function of temperature will be useful in managing the benefits and risks of hypothermia. METHODS AND RESULTS We perform two-dimensional numerical simulations by using a minimal model of cardiac action potential propagation fine-tuned on experimental measurements. The model includes thermal factors acting on the ionic currents and the gating variables to correctly reproduce experimentally recorded restitution curves at different temperatures. Simulations are implemented using WebGL, which allows long simulations to be performed as they run close to real time. We describe (i) why fibrillation is easier to induce at low temperatures, (ii) that there is a minimum size required for fibrillation that depends on temperature, (iii) why the frequency of fibrillation decreases with decreasing temperature, and (iv) that regional cooling may be an anti-arrhythmic therapy for small tissue sizes however it may be pro-arrhythmic for large tissue sizes. CONCLUSION Using a mathematical cardiac cell model, we are able to reproduce experimental observations, quantitative experimental results, and discuss possible mechanisms and implications of electrophysiological changes during hypothermia.
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Affiliation(s)
- Simonetta Filippi
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
- International Center for Relativistic Astrophysics—I.C.R.A, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
| | - Alessio Gizzi
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
- International Center for Relativistic Astrophysics—I.C.R.A, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
| | - Christian Cherubini
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
- International Center for Relativistic Astrophysics—I.C.R.A, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
| | - Stefan Luther
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, D-37077 Göttingen, Germany
| | - Flavio H. Fenton
- School of Physics, Georgia Institute of Technology, 837 State Street Atlanta, Atlanta, GA 30332, USA
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Kim SM, Hwang GS, Park JS, Shin JS, Kim GW, Yang HM, Choi SY, Yoon MH, Shin JH, Tahk SJ. The pattern of Tpeak–Tend and QT interval, and J wave during therapeutic hypothermia. J Electrocardiol 2014; 47:84-92. [DOI: 10.1016/j.jelectrocard.2013.05.139] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Indexed: 10/26/2022]
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Bassin L, Yong AC, Kilpatrick D, Hunyor SN. Arrhythmogenicity of Hypothermia – A Large Animal Model of Hypothermia. Heart Lung Circ 2014; 23:82-7. [DOI: 10.1016/j.hlc.2013.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 06/29/2013] [Accepted: 07/02/2013] [Indexed: 01/08/2023]
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Guilliams K, Rosen M, Buttram S, Zempel J, Pineda J, Miller B, Shoykhet M. Hypothermia for pediatric refractory status epilepticus. Epilepsia 2013; 54:1586-94. [PMID: 23906244 DOI: 10.1111/epi.12331] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2013] [Indexed: 11/27/2022]
Abstract
PURPOSE Refractory status epilepticus (RSE) is a life-threatening emergency, demonstrating, by definition, significant pharmacoresistance. We describe five cases of pediatric RSE treated with mild hypothermia. METHODS Retrospective chart review was performed of records of children who received hypothermia for RSE at two tertiary-care pediatric hospitals between 2009 and 2012. KEY FINDINGS Five children with RSE received mild hypothermia (32-35°C). Hypothermia reduced seizure burden during and after treatment in all cases. Prior to initiation of hypothermia, four children (80%) received pentobarbital infusions to treat RSE, but relapsed after pentobarbital discontinuation. No child relapsed after treatment with hypothermia. One child died after redirection of care. Remaining four children were discharged. SIGNIFICANCE This is the largest pediatric case series reporting treatment of RSE with mild hypothermia. Hypothermia decreased seizure burden during and after pediatric RSE and may prevent RSE relapse.
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Affiliation(s)
- Kristin Guilliams
- Division of Pediatric and Developmental Neurology, Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA.
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Weitz D, Greet B, Bernstein SA, Holmes DS, Bernstein N, Aizer A, Chinitz L, Roswell RO. The benign nature of mild induced therapeutic hypothermia--induced long QTc. Int J Cardiol 2013; 168:1583-5. [PMID: 23410493 DOI: 10.1016/j.ijcard.2013.01.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 01/18/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Daniel Weitz
- The Division of Cardiology, New York University School of Medicine, New York, United States
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Piktel JS, Rosenbaum DS, Wilson LD. Mild hypothermia decreases arrhythmia susceptibility in a canine model of global myocardial ischemia*. Crit Care Med 2013; 40:2954-9. [PMID: 22890250 DOI: 10.1097/ccm.0b013e31825fd39d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Although the majority of sudden cardiac arrests occur in patients with ischemic heart disease, the effect of therapeutic hypothermia on arrhythmia susceptibility during acute global ischemia is not well understood. While both ischemia and severe hypothermia are arrhythmogenic, patients undergoing therapeutic hypothermia do not have an increase in arrhythmias, despite the fact that most sudden cardiac arrest occur in the setting of ischemia. We hypothesized that mild hypothermia induced prior to myocardial ischemia and reperfusion will have a beneficial effect on ischemia-related arrhythmia substrates. DESIGN We developed a model of global ischemia and reperfusion in the canine wedge preparation to study the transmural electrophysiologic effects of ischemia at different temperatures. SETTING Animal study. SUBJECTS Male mongrel dogs. INTERVENTIONS Canine left ventricle wedge preparations at 1) control (36°C) or 2) mild hypothermia, to simulate temperatures used in therapeutic hypothermia (32°C), were subjected to 15 mins of no-flow ischemia and subsequently reperfused. MEASUREMENTS AND MAIN RESULTS Optical action potentials were recorded spanning the transmural wall of left ventricle. Action potential duration for epicardial, mid-myocardial, and epicardial cells was measured. Transmural dispersion of repolarization and conduction velocity were measured at baseline, during ischemia, and during reperfusion. No difference was seen at baseline for conduction velocity or dispersion of repolarization between groups. Conduction velocity decreased from 0.46 ± 0.02 m/sec to 0.23 ± 0.07 m/sec, and dispersion of repolarization increased from 30 ± 5 msecs to 57 ± 4 msecs in the control group at 15 mins of ischemia. Mild hypothermia attenuated both the ischemia-induced conduction velocity slowing (decreasing from 0.44 ± 0.02 m/sec to 0.35 ± 0.03 m/sec; p = .019) and the ischemia-induced increase in dispersion of repolarization (25 ± 3 msecs to 37 ± 7 msecs; p = .037). Epicardial conduction block was observed in six of seven preparations of the control group, but no preparations in the mild hypothermia group developed conduction block (0/6). CONCLUSIONS Mild hypothermia attenuated ischemia-induced increase in dispersion of repolarization, conduction slowing, and block, which are known mechanisms of arrhythmogenesis in ischemia. These data suggest that therapeutic hypothermia may decrease arrhythmogenesis during myocardial ischemia.
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Affiliation(s)
- Joseph S Piktel
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
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Lebiedz P, Meiners J, Samol A, Wasmer K, Reinecke H, Waltenberger J, Eckardt L. Electrocardiographic changes during therapeutic hypothermia. Resuscitation 2012; 83:602-6. [DOI: 10.1016/j.resuscitation.2011.11.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Revised: 11/01/2011] [Accepted: 11/10/2011] [Indexed: 10/15/2022]
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Bader MK. Clinical q & a: translating therapeutic temperature management from theory to practice. Ther Hypothermia Temp Manag 2012; 2:44-7. [PMID: 24717137 DOI: 10.1089/ther.2012.1500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Affiliation(s)
| | - Roy M. John
- From the Brigham and Women's Hospital, Boston, MA
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Varró A, Baczkó I. Cardiac ventricular repolarization reserve: a principle for understanding drug-related proarrhythmic risk. Br J Pharmacol 2011; 164:14-36. [PMID: 21545574 PMCID: PMC3171857 DOI: 10.1111/j.1476-5381.2011.01367.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/22/2011] [Accepted: 03/02/2011] [Indexed: 12/11/2022] Open
Abstract
Cardiac repolarization abnormalities can be caused by a wide range of cardiac and non-cardiac compounds and may lead to the development of life-threatening Torsades de Pointes (TdP) ventricular arrhythmias. Drug-induced torsades de pointes is associated with unexpected and unexplained sudden cardiac deaths resulting in the withdrawal of several compounds in the past. To better understand the mechanism of such unexpected sudden cardiac deaths, the concept of repolarization reserve has recently emerged. According to this concept, pharmacological, congenital or acquired impairment of one type of transmembrane ion channel does not necessarily result in excessive repolarization changes because other repolarizing currents can take over and compensate. In this review, the major factors contributing to repolarization reserve are discussed in the context of their clinical significance in physiological and pathophysiological conditions including drug administration, genetic defects, heart failure, diabetes mellitus, gender, renal failure, hypokalaemia, hypothyroidism and athletes' sudden deaths. In addition, pharmacological support of repolarization reserve as a possible therapeutic option is discussed. Some methods for the quantitative estimation of repolarization reserve are also recommended. It is concluded that repolarization reserve should be considered by safety pharmacologists to better understand, predict and prevent previously unexplained drug-induced sudden cardiac deaths.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary.
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