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Oliveira C, Pinho A, Santos L, Pinto RA, Oliveira S, Moreira H, Rocha M, Palma P, Pestana G, Madeira M, Lebreiro A, Adão L. Long-term prognosis of idiopathic ventricular fibrillation: An eighteen-year experience from a tertiary center. Rev Port Cardiol 2024; 43:331-336. [PMID: 38615880 DOI: 10.1016/j.repc.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/22/2024] [Accepted: 04/02/2024] [Indexed: 04/16/2024] Open
Abstract
INTRODUCTION AND OBJECTIVES Idiopathic ventricular fibrillation (IVF) is diagnosed in patients who survive sudden cardiac arrest (SCA), preferably with documented ventricular fibrillation (VF), without any identifiable structural or electrical abnormality. Current evidence provides limited guidance on the diagnosis and follow-up of these patients. Our aim was to assess the clinical outcomes of survivors of an aborted SCA attributed to IVF. METHODS We retrospectively collected clinical data from all patients who survived SCA and implanted a cardiac defibrillator (ICD) between 2005 and 2023. RESULTS A total of 38 patients, 36.8% female, with a mean age of 44±14 years old were included. Median follow-up time was 8.7 years (interquartile range (IQR) 4.7-14.7 years). All patients underwent a comprehensive diagnostic evaluation that excluded structural and coronary disease. During follow-up, underlying diagnoses were established in 34.2% of the whole cohort. Genetic testing, performed in 37.2%, revealed underlying diagnoses in 57.1% of those tested, compared to only 26.3% of patients who did not undergo genetic testing [p=0.035, OR=5.1 (95% confidence interval (CI) 1.2-21.5)]. Mortality was 10.5% (due to non-arrhythmic causes) and 36.8% patients received appropriate therapies with a median time to first ICD therapy of 39 [5.4-47.3] months. CONCLUSION(S) Etiological diagnosis and recurrence prediction in patients with IVF remains challenging, even with extensive diagnostic evaluation and long-term follow-up. In our study, genetic testing enhanced diagnostic yield. Consistent with previous findings, our cohort experienced a notable arrhythmic recurrence, with no cardiac deaths, underlining the pivotal role of ICD implantation in these patients.
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Affiliation(s)
- Cátia Oliveira
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal.
| | - Ana Pinho
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
| | - Luís Santos
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
| | - Ricardo Alves Pinto
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
| | - Sílvia Oliveira
- Faculty of Medicine of University of Oporto, Porto, Portugal
| | - Helena Moreira
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
| | - Miguel Rocha
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
| | - Pedro Palma
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
| | - Gonçalo Pestana
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
| | - Marta Madeira
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
| | - Ana Lebreiro
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
| | - Luís Adão
- Department of Cardiology, Local Health Unit of São João, E.P.E., Porto, Portugal
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Lenarczyk R, Zeppenfeld K, Tfelt-Hansen J, Heinzel FR, Deneke T, Ene E, Meyer C, Wilde A, Arbelo E, Jędrzejczyk-Patej E, Sabbag A, Stühlinger M, di Biase L, Vaseghi M, Ziv O, Bautista-Vargas WF, Kumar S, Namboodiri N, Henz BD, Montero-Cabezas J, Dagres N. Management of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC-endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society. Europace 2024; 26:euae049. [PMID: 38584423 PMCID: PMC10999775 DOI: 10.1093/europace/euae049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 04/09/2024] Open
Abstract
Electrical storm (ES) is a state of electrical instability, manifesting as recurrent ventricular arrhythmias (VAs) over a short period of time (three or more episodes of sustained VA within 24 h, separated by at least 5 min, requiring termination by an intervention). The clinical presentation can vary, but ES is usually a cardiac emergency. Electrical storm mainly affects patients with structural or primary electrical heart disease, often with an implantable cardioverter-defibrillator (ICD). Management of ES requires a multi-faceted approach and the involvement of multi-disciplinary teams, but despite advanced treatment and often invasive procedures, it is associated with high morbidity and mortality. With an ageing population, longer survival of heart failure patients, and an increasing number of patients with ICD, the incidence of ES is expected to increase. This European Heart Rhythm Association clinical consensus statement focuses on pathophysiology, clinical presentation, diagnostic evaluation, and acute and long-term management of patients presenting with ES or clustered VA.
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Affiliation(s)
- Radosław Lenarczyk
- Medical University of Silesia, Division of Medical Sciences, Department of Cardiology and Electrotherapy, Silesian Center for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland
| | - Katja Zeppenfeld
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jacob Tfelt-Hansen
- The Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- The Department of Forensic Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Frank R Heinzel
- Cardiology, Angiology, Intensive Care, Städtisches Klinikum Dresden Campus Friedrichstadt, Dresden, Germany
| | - Thomas Deneke
- Clinic for Interventional Electrophysiology, Heart Center RHÖN-KLINIKUM Campus Bad Neustadt, Bad Neustadt an der Saale, Germany
- Clinic for Electrophysiology, Klinikum Nuernberg, University Hospital of the Paracelsus Medical University, Nuernberg, Germany
| | - Elena Ene
- Clinic for Interventional Electrophysiology, Heart Center RHÖN-KLINIKUM Campus Bad Neustadt, Bad Neustadt an der Saale, Germany
| | - Christian Meyer
- Division of Cardiology/Angiology/Intensive Care, EVK Düsseldorf, Teaching Hospital University of Düsseldorf, Düsseldorf, Germany
| | - Arthur Wilde
- Department of Cardiology, Amsterdam UMC University of Amsterdam, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and arrhythmias, Amsterdam, the Netherlands
| | - Elena Arbelo
- Arrhythmia Section, Cardiology Department, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain; IDIBAPS, Institut d'Investigació August Pi i Sunyer (IDIBAPS), Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Ewa Jędrzejczyk-Patej
- Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Centre for Heart Diseases, Zabrze, Poland
| | - Avi Sabbag
- The Davidai Center for Rhythm Disturbances and Pacing, Chaim Sheba Medical Center, Tel Hashomer, Israel
- School of Medicine, Faculty of Medical and Health Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Markus Stühlinger
- Department of Internal Medicine III, Cardiology and Angiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Luigi di Biase
- Albert Einstein College of Medicine at Montefiore Hospital, New York, NY, USA
| | - Marmar Vaseghi
- UCLA Cardiac Arrythmia Center, Division of Cardiology, Department of Medicine, University of California, Los Angeles, CA, USA
| | - Ohad Ziv
- Case Western Reserve University, Cleveland, OH, USA
- The MetroHealth System Campus, Cleveland, OH, USA
| | | | - Saurabh Kumar
- Department of Cardiology, Westmead Hospital, Westmead Applied Research Centre, University of Sydney, Sydney, Australia
| | | | - Benhur Davi Henz
- Instituto Brasilia de Arritmias-Hospital do Coração do Brasil-Rede Dor São Luiz, Brasilia, Brazil
| | - Jose Montero-Cabezas
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
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Badura K, Buławska D, Dąbek B, Witkowska A, Lisińska W, Radzioch E, Skwira S, Młynarska E, Rysz J, Franczyk B. Primary Electrical Heart Disease-Principles of Pathophysiology and Genetics. Int J Mol Sci 2024; 25:1826. [PMID: 38339103 PMCID: PMC10855675 DOI: 10.3390/ijms25031826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/27/2024] [Accepted: 01/28/2024] [Indexed: 02/12/2024] Open
Abstract
Primary electrical heart diseases, often considered channelopathies, are inherited genetic abnormalities of cardiomyocyte electrical behavior carrying the risk of malignant arrhythmias leading to sudden cardiac death (SCD). Approximately 54% of sudden, unexpected deaths in individuals under the age of 35 do not exhibit signs of structural heart disease during autopsy, suggesting the potential significance of channelopathies in this group of age. Channelopathies constitute a highly heterogenous group comprising various diseases such as long QT syndrome (LQTS), short QT syndrome (SQTS), idiopathic ventricular fibrillation (IVF), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and early repolarization syndromes (ERS). Although new advances in the diagnostic process of channelopathies have been made, the link between a disease and sudden cardiac death remains not fully explained. Evolving data in electrophysiology and genetic testing suggest previously described diseases as complex with multiple underlying genes and a high variety of factors associated with SCD in channelopathies. This review summarizes available, well-established information about channelopathy pathogenesis, genetic basics, and molecular aspects relative to principles of the pathophysiology of arrhythmia. In addition, general information about diagnostic approaches and management is presented. Analyzing principles of channelopathies and their underlying causes improves the understanding of genetic and molecular basics that may assist general research and improve SCD prevention.
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Affiliation(s)
- Krzysztof Badura
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Dominika Buławska
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Bartłomiej Dąbek
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Alicja Witkowska
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Wiktoria Lisińska
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Ewa Radzioch
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Sylwia Skwira
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Ewelina Młynarska
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Jacek Rysz
- Department of Nephrology, Hypertension and Family Medicine, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland
| | - Beata Franczyk
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
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Miller JA, Moise N, Weinberg SH. Modeling incomplete penetrance in long QT syndrome type 3 through ion channel heterogeneity: an in silico population study. Am J Physiol Heart Circ Physiol 2023; 324:H179-H197. [PMID: 36487185 PMCID: PMC10072004 DOI: 10.1152/ajpheart.00430.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 11/16/2022] [Accepted: 11/29/2022] [Indexed: 12/14/2022]
Abstract
Many cardiac diseases are characterized by an increased late sodium current, including heart failure, hypertrophic cardiomyopathy, and inherited long QT syndrome type 3 (LQT3). The late sodium current in LQT3 is caused by a gain-of-function mutation in the voltage-gated sodium channel Nav1.5. Despite a well-defined genetic cause of LQT3, treatment remains inconsistent because of incomplete penetrance of the mutation and variability of antiarrhythmic efficacy. Here, we investigate the relationship between LQT3-associated mutation incomplete penetrance and variability in ion channel expression, simulating a population of 1,000 individuals with the O'Hara-Rudy model of the human ventricular myocyte. We first simulate healthy electrical activity (i.e., in the absence of a mutation) and then incorporate heterozygous expression for three LQT3-associated mutations (Y1795C, I1768V, and ΔKPQ), to directly compare the effects of each mutation on individuals across a diverse population. For all mutations, we find that susceptibility, defined by either the presence of an early afterdepolarization (EAD) or prolonged action potential duration (APD), primarily depends on the balance between the conductance of IKr and INa, for which individuals with a higher IKr-to-INa ratio are less susceptible. Furthermore, we find distinct differences across the population, observing individuals susceptible to zero, one, two, or all three mutations. Individuals tend to be less susceptible with an appropriate balance of repolarizing currents, typically via increased IKs or IK1. Interestingly, the more critical repolarizing current is mutation specific. We conclude that the balance between key currents plays a significant role in mutant-specific presentation of the disease phenotype in LQT3.NEW & NOTEWORTHY An in silico population approach investigates the relationship between variability in ion channel expression and gain-of-function mutations in the voltage-gated sodium channel associated with the congenital disorder long QT syndrome type 3 (LQT3). We find that ion channel variability can contribute to incomplete penetrance of the mutation, with mutant-specific differences in ion channel conductances leading to susceptibility to proarrhythmic action potential duration prolongation or early afterdepolarizations.
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Affiliation(s)
- Jacob A Miller
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
| | - Nicolae Moise
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
| | - Seth H Weinberg
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
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Wang G, Zhong L, Chu H, Wang C, Zhu X. Short-coupled variant of torsade de pointes: A systematic review of case reports and case series. Front Cardiovasc Med 2022; 9:922525. [PMID: 36035953 PMCID: PMC9411750 DOI: 10.3389/fcvm.2022.922525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/22/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundThe short-coupled variant of torsade de pointes (scTdP) is characterized by a particular electrocardiogram (ECG) pattern that shows a short-coupling interval of the initial Tdp beat and that can degenerate into ventricular fibrillation without the presence of structural heart disease. However, its etiology, epidemiology, clinical characteristics, underlying mechanism, treatment, and prognosis remain unclear. This study aimed to systematically review case reports and series of scTdP to synthesize existing data on the demography, clinical characteristics, ECG features, management, and outcomes.MethodsA literature search was conducted for eligible published articles using the Medline, Embase, and PubMed databases. All eligible case reports and case series were included without any language restrictions. SPSS 24 was used for statistical analysis.ResultsA total of 22 case reports and 103 case series of patients with scTdP were identified and included in the analysis. All selected cases had acceptable quality of evidence. Most young patients without sex differences had no trigger or a negative programmed simulation. The ECGs of all selected patients showed a short first-coupling interval (302 ± 62 ms) and a long QRS duration of ventricular extrasystole (VE) (135 ± 17 ms). The first coupling interval levels and QRS duration levels of VE were significantly longer and wider in patients with scTdP originating from the right ventricular outflow tract (RVOT) than in those with scTdP originating from the Purkinje fibers (380 ± 70 vs. 274 ± 28 ms, P < 0.001; 147 ± 8 vs. 131 ± 17 ms, P < 0.001), respectively. The receiver operating characteristic curve showed that the optimal cutoff values of the first coupling interval triggering TdP and QRS duration of VE were more than 319 ms and 141 ms (92% sensitivity, 95.7% specificity; 82.6% sensitivity, 77.8% specificity) for predicting the RVOT origin, respectively. The Kaplan-Meier survival curve revealed increased survival in patients with implantable cardioverter defibrillator (ICD) implantation than in patients without ICD implantation (log-rank =10.127, P = 0.001).ConclusionSome agreements were confirmed in selected case reports regarding the clinical features, diagnosis, and management of scTdPs. Further large-scale and long-term follow-up studies are required to clarify the existing arrhythmogenic entities.
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Hashmath Z, Naniwadekar A. Idiopathic Ventricular Fibrillation Triggered by Premature Ventricular Complexes Originating from the False Tendon of the Left Ventricle. HeartRhythm Case Rep 2022; 8:515-519. [PMID: 35860782 PMCID: PMC9289068 DOI: 10.1016/j.hrcr.2022.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Belhassen B, Tovia-Brodie O. Short-Coupled Idiopathic Ventricular Fibrillation: A Literature Review With Extended Follow-Up. JACC Clin Electrophysiol 2022; 8:918-936. [PMID: 35597766 DOI: 10.1016/j.jacep.2022.04.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/25/2022] [Accepted: 04/18/2022] [Indexed: 01/07/2023]
Abstract
Idiopathic ventricular fibrillation is responsible for approximately 10% of cases of aborted cardiac arrest. Recent studies have shown that short-coupled ventricular premature complexes are present at the onset of idiopathic ventricular fibrillation in 6.6%-17% of patients. The present review provided information on 86 patients with short-coupled malignant ventricular arrhythmias that were reported as case reports or small patient series during the last 70 years. In 75% of the 81 cases published during the last 40 years, extended information and follow-up (from 2.63 ± 4.5 to 10.67 ± 7.8 years; P < 0.001, between the original publication to the latest update) could be obtained from the authors. The review shows that short-coupled malignant ventricular arrhythmias occurred almost equally in males and females, at the mean age of 40 years. A tendency for later occurrence of the arrhythmia by 4 years was observed in females. A prior history of syncope was noted in 45.3% of the patients, whereas arrhythmic storm occurred in 42% at presentation. The most common mode of revelation of short-coupled malignant ventricular arrhythmias was syncope (53.5%), followed by aborted cardiac arrest (26.7%) and recurrent arrhythmic event after prior implantable-cardioverter defibrillator implantation for idiopathic ventricular fibrillation (17.4%). For the first time, short-coupled malignant arrhythmias exhibiting "not-so-short" coupling intervals (≥350 ms) were found in a significant proportion of patients (17.4%). During long-term follow-up, quinidine yielded a slightly higher success rate in arrhythmia control than ablation. Larger studies are necessary to assess the best strategy for the management of this potentially lethal arrhythmia.
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Affiliation(s)
- Bernard Belhassen
- Heart Institute, Hadassah Medical Center, Jerusalem, Israel; Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
| | - Oholi Tovia-Brodie
- Jesselson Integrated Heart Center, Shaare Zedek Medical Center, Jerusalem, Israel; Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva, Israel
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Katis G, Wiles B, Saba MM. Short-coupled ventricular ectopics leading to cardiac arrest in a young woman. Egypt Heart J 2022; 74:32. [PMID: 35467248 PMCID: PMC9038978 DOI: 10.1186/s43044-022-00272-y] [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: 11/24/2021] [Accepted: 04/12/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND This case report highlights the importance of recognizing that ventricular ectopy may be a cause for syncope and sudden cardiac death, through triggered disorganized arrhythmia. In the context of syncope, ventricular ectopy should be carefully assessed for coupling interval and morphology. CASE PRESENTATION A 39-year-old woman, who had presented with recurrent syncope, had a cardiac arrest shortly after admission that required emergency defibrillation. Review of her cardiac monitoring revealed an episode of polymorphic ventricular tachycardia which had degenerated into ventricular fibrillation. The dysrhythmia had been initiated by a short-coupled (R-on-T) ventricular ectopic (VE) beat. Anti-arrhythmic therapy was initiated in the form of hydroquinidine, but the patient continued to have frequent VEs of right bundle branch block (RBBB) morphology with a relatively narrow QRS complex and a variation in frontal axis. A cardiac MRI revealed late gadolinium enhancement of the posterior papillary muscle (indicative of focal scarring). The patient underwent electrophysiological mapping and catheter ablation of her ectopy. The patient made a good recovery and was discharged from hospital with a secondary prevention implantable cardioverter-defibrillator (ICD) in situ. CONCLUSIONS Short-couped VEs that are superimposed onto the preceding T wave (R-on-T) are indicative of electrical instability of the heart and should prompt urgent investigation. By studying the morphologies and axes of the QRS complexes produced by VEs, we can identify their likely origins and ascertain their clinical significance.
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Affiliation(s)
| | - Benedict Wiles
- Advanced Ventricular Arrythmia Training and Research (AVATAR) Program at St. George's Hospital, London, UK
| | - Magdi M Saba
- Advanced Ventricular Arrythmia Training and Research (AVATAR) Program at St. George's Hospital, London, UK
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Uzelac I, Fenton FH. Personalized Low-Energy Defibrillation Through Feedback Based Resynchronization Therapy. COMPUTING IN CARDIOLOGY 2020; 2020:10.22489/cinc.2020.471. [PMID: 34423055 PMCID: PMC8378784 DOI: 10.22489/cinc.2020.471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AIMS Defibrillation shocks may cause AV node burnout, scar formation, and pain. In this study, we present a real-time feedback-based control of ventricular fibrillation (VF) with a series of low-energy shocks using ventricular electrical activity as the feedback input. METHODS Isolated rabbit hearts were Langendorff perfused and stained with a fluorescent Vm dye. The ventricular activity was measured with a pair of photodiodes, and processed with a feedback controller to calculate defibrillation shock parameters in real-time. Shock timing was based on desynchronized activation of the left and right ventricles during VF, and the strength was proportional to the amplitude difference of the photodiode signals. Shocks were delivered with a custom-developed arbitrary waveform trans-conductance amplifier. RESULTS Feedback based resynchronization therapy converts VT to MT before sinus rhythm is restored with a reduction of defibrillation energy, compared to a single biphasic shock. CONCLUSIONS Feedback based resynchronization therapy is based on real-time sensing of ventricular activity, while a series of low-energy shocks are delivered, reducing the risk of associated side effects.
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Affiliation(s)
- Ilija Uzelac
- School of Physics - Georgia Institute of Technology, USA
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