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Pujol-Lopez M, Du Fay de Lavallaz J, Rangan P, Beaser A, Aziz Z, Upadhyay GA, Nayak H, Weiss JP, Zawaneh M, Bai R, Su W, Tung R. Vasovagal Responses to Human Monomorphic Ventricular Tachycardia: Hemodynamic Implications From Sinus Rate Analysis. J Am Coll Cardiol 2023; 82:1096-1105. [PMID: 37673510 DOI: 10.1016/j.jacc.2023.06.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/30/2023] [Accepted: 06/12/2023] [Indexed: 09/08/2023]
Abstract
BACKGROUND Factors determining hemodynamic stability during human ventricular tachycardia (VT) are incompletely understood. OBJECTIVES The purposes of this study were to characterize sinus rate (SR) responses during monomorphic VT in association with hemodynamic stability and to prospectively assess the effects of vagolytic therapy on VT tolerance. METHODS This is a retrospective analysis of patients undergoing scar-related VT ablation. Vasovagal responses were evaluated by analyzing sinus cycle length before VT induction and during VT. SR responses were classified into 3 groups: increasing (≥5 beats/min, sympathetic), decreasing (≥5 beats/min, vagal), and unchanged, with the latter 2 categorized as inappropriate SR. In a prospective cohort (n = 30) that exhibited a failure to increase SR, atropine was administered to improve hemodynamic tolerance to VT. RESULTS In 150 patients, 261 VT episodes were analyzed (29% untolerated, 71% tolerated) with median VT duration 1.6 minutes. A total of 52% of VT episodes were associated with a sympathetic response, 31% had unchanged SR, and 17% of VTs exhibited a vagal response. A significantly higher prevalence of inappropriate SR responses was observed during untolerated VT (sustained VT requiring cardioversion within 150 seconds) compared with tolerated VT (84% vs 34%; P < 0.001). Untolerated VT was significantly different between groups: 9% (sympathetic), 82% (vagal), and 32% (unchanged) (P < 0.001). Atropine administration improved hemodynamic tolerance to VT in 70%. CONCLUSIONS Nearly one-half of VT episodes are associated with failure to augment SR, indicative of an under-recognized pathophysiological vasovagal response to VT. Inappropriate SR responses were more predictive of hemodynamic instability than VT rate and ejection fraction. Vagolytic therapy may be a novel method to augment blood pressure during VT.
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Affiliation(s)
- Margarida Pujol-Lopez
- University of Chicago Medicine, Center for Arrhythmia Care, Pritzker School of Medicine, Section of Cardiology, Chicago, Illinois, USA; University of Arizona College of Medicine, Banner-University Medical Center, Division of Cardiology, Phoenix, Arizona, USA
| | - Jeanne Du Fay de Lavallaz
- University of Chicago Medicine, Center for Arrhythmia Care, Pritzker School of Medicine, Section of Cardiology, Chicago, Illinois, USA
| | - Pooja Rangan
- University of Arizona College of Medicine, Banner-University Medical Center, Division of Cardiology, Phoenix, Arizona, USA
| | - Andrew Beaser
- University of Chicago Medicine, Center for Arrhythmia Care, Pritzker School of Medicine, Section of Cardiology, Chicago, Illinois, USA
| | - Zaid Aziz
- University of Chicago Medicine, Center for Arrhythmia Care, Pritzker School of Medicine, Section of Cardiology, Chicago, Illinois, USA
| | - Gaurav A Upadhyay
- University of Chicago Medicine, Center for Arrhythmia Care, Pritzker School of Medicine, Section of Cardiology, Chicago, Illinois, USA
| | - Hemal Nayak
- University of Chicago Medicine, Center for Arrhythmia Care, Pritzker School of Medicine, Section of Cardiology, Chicago, Illinois, USA
| | - J Peter Weiss
- University of Arizona College of Medicine, Banner-University Medical Center, Division of Cardiology, Phoenix, Arizona, USA
| | - Michael Zawaneh
- University of Arizona College of Medicine, Banner-University Medical Center, Division of Cardiology, Phoenix, Arizona, USA
| | - Rong Bai
- University of Arizona College of Medicine, Banner-University Medical Center, Division of Cardiology, Phoenix, Arizona, USA
| | - Wilber Su
- University of Arizona College of Medicine, Banner-University Medical Center, Division of Cardiology, Phoenix, Arizona, USA
| | - Roderick Tung
- University of Arizona College of Medicine, Banner-University Medical Center, Division of Cardiology, Phoenix, Arizona, USA.
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d'Avila A, D'Angelo RN. Vasovagal Responses to Human Monomorphic Ventricular Tachycardia: Atropine to the Rescue. J Am Coll Cardiol 2023; 82:1106-1107. [PMID: 37673511 DOI: 10.1016/j.jacc.2023.06.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 09/08/2023]
Affiliation(s)
- Andre d'Avila
- Harvard-Thorndike Electrophysiology Institute, Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
| | - Robert N D'Angelo
- Harvard-Thorndike Electrophysiology Institute, Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA. https://twitter.com/rdangeloMD
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Shen WK, Sheldon RS, Benditt DG, Cohen MI, Forman DE, Goldberger ZD, Grubb BP, Hamdan MH, Krahn AD, Link MS, Olshansky B, Raj SR, Sandhu RK, Sorajja D, Sun BC, Yancy CW. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation 2017; 136:e60-e122. [DOI: 10.1161/cir.0000000000000499] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Win-Kuang Shen
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | | | - David G. Benditt
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Mitchell I. Cohen
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Daniel E. Forman
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Zachary D. Goldberger
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Blair P. Grubb
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Mohamed H. Hamdan
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Andrew D. Krahn
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Mark S. Link
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Brian Olshansky
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Satish R. Raj
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Roopinder Kaur Sandhu
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Dan Sorajja
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Benjamin C. Sun
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Clyde W. Yancy
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
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Shen WK, Sheldon RS, Benditt DG, Cohen MI, Forman DE, Goldberger ZD, Grubb BP, Hamdan MH, Krahn AD, Link MS, Olshansky B, Raj SR, Sandhu RK, Sorajja D, Sun BC, Yancy CW. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm 2017; 14:e155-e217. [PMID: 28286247 DOI: 10.1016/j.hrthm.2017.03.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 12/26/2022]
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Mechanisms of sinus node cycle length changes during ventricular fibrillation. Clin Auton Res 2015; 25:399-406. [PMID: 26596875 DOI: 10.1007/s10286-015-0319-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 09/18/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVE We have previously shown that up to one-third of patients develop no change or an increase in sinus node cycle length (SNCL) during ventricular fibrillation (VF). The purpose of the present study was to investigate the mechanism of SNCL changes during VF in a swine model. We hypothesized that changes in SNCL during VF are vagally-mediated. METHODS In 33 anesthetized pigs DC current was used to induce VF for 10 s followed by defibrillation. SNCL changes were assessed during VF and compared to baseline. Animals that had ventriculo-atrial conduction during VF were excluded. Post-defibrillation, the pigs were randomized to receive atropine, propranolol, atropine + propranolol or placebo followed by repeat VF induction and measurement of SNCL changes. RESULTS Ventriculo-atrial conduction was present in 14 pigs prohibiting SNCL measurements. In the remaining 19 animals, 10 demonstrated SNCL shortening (S-Group) and 9 demonstrated non-shortening (NS-Group). Atropine decreased the absolute change in SNCL from 51.2 to 26.6 ms (n = 6; p = 0.03). It attenuated the SNCL shortening previously observed in the S-Group (-99.2 ms versus -47.9 ms, p = 0.04) and reversed the SNCL prolongation initially observed in the NS-Group (27.1 ms versus -6.5 ms, p = 0.13). Similarly, atropine + propranolol decreased the absolute change in SNCL from 33.3 to 12.2 ms (n = 4; p = 0.05). No significant changes were noted with propranolol or placebo. INTERPRETATION The SNCL changes during VF appear to be vagally-mediated. The clinical implications vis-à-vis defibrillation threshold and future device programming await future studies.
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Safavi-Naeini P, Rasekh A, Razavi M, Saeed M, Massumi A. Sudden Cardiac Death in Coronary Artery Disease. Coron Artery Dis 2015. [DOI: 10.1007/978-1-4471-2828-1_24] [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: 11/28/2022]
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MYERBURG ROBERTJ, KESSLER KENNETHM, KIMURA SHINICHI, CASTELLANOS AGUSTIN. Sudden Cardiac Death: Future Approaches Based on Identification and Control of Transient Risk Factors. J Cardiovasc Electrophysiol 2013. [DOI: 10.1111/j.1540-8167.1992.tb01941.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kroll MW, Fish RM, Lakkireddy D, Luceri RM, Panescu D. Essentials of low-power electrocution: established and speculated mechanisms. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2012:5734-5740. [PMID: 23367232 DOI: 10.1109/embc.2012.6347297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Even though electrocution has been recognized--and studied--for over a century, there remain several common misconceptions among medical professional as well as lay persons. This review focuses on "low-power" electrocutions rather than on the "high-power" electrocutions such as from lightning and power lines. Low-power electrocution induces ventricular fibrillation (VF). We review the 3 established mechanisms for electrocution: (1) shock on cardiac T-wave, (2) direct induction of VF, and (3) long-term high-rate cardiac capture reducing the VF threshold until VF is induced. There are several electrocution myths addressed, including the concept--often taught in medical school--that direct current causes asystole instead of VF and that electrical exposure can lead to a delayed cardiac arrest by inducing a subclinical ventricular tachycardia (VT). Other misunderstandings are also discussed.
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Affiliation(s)
- Mark W Kroll
- Biomedical Engineering Dept., University of Minnesota, Minneapolis, MN, USA.
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10
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Wasmund SL, Pai RK, Freedman RA, Abedin M, Daccarett M, Segerson NM, Zaitsev AV, Hamdan MH. Modulation of the sinus rate during ventricular fibrillation. J Cardiovasc Electrophysiol 2009; 20:187-92. [PMID: 19220574 DOI: 10.1111/j.1540-8167.2008.01314.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND During supraventricular and ventricular tachycardia, the arterial baroreflex predominates with minimal contribution from the cardiopulmonary reflex. To our knowledge, the role of the arterial baroreflex gain (BRG) during and immediately following termination of ventricular fibrillation (VF) has not been characterized. OBJECTIVE We hypothesized that (1) arterial BRG correlated with sinus node cycle length (SNCL) changes during VF, and that (2) the greater the arterial BRG, the greater the blood pressure (BP) recovery following successful defibrillation. METHODS Arterial BRG was assessed in 18 patients referred for the implantation of a defibrillator incorporating an atrial lead. The average SNCL was measured during the 5 seconds prior to VF induction and the last 5 seconds during VF before defibrillation. Percent SNCL change (%DeltaSNCL) was determined. Arterial BP recovery was calculated as the difference in mean BP following defibrillation compared to during VF. RESULTS Arterial BRG ranged between -3 and 18 ms/mmHg. During VF, SNCL shortened in 11 patients (group A, mean %DeltaSNCL =-15%), and surprisingly lengthened in seven patients (group B, mean %DeltaSNCL = 5%). There was no correlation between %DeltaSNCL and arterial BRG. In fact, arterial BRG in group A was lower when compared with group B (P = 0.075). Similarly, there was no correlation between arterial BRG and BP recovery. CONCLUSIONS We found no correlation between arterial BRG and %DeltaSNCL during VF, or BP recovery following defibrillation. Our findings of SNCL lengthening in 7 of 18 patients suggest that in some patients, arterial BRG plays a minor role during VF with a greater contribution from the cardiopulmonary BRG.
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Affiliation(s)
- Stephen L Wasmund
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah 84112-5000, USA.
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Sweeney MO. Antitachycardia pacing for ventricular tachycardia using implantable cardioverter defibrillators:. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2005; 27:1292-305. [PMID: 15461721 DOI: 10.1111/j.1540-8159.2004.00622.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Michael O Sweeney
- CRM Research, Cardiac Arrhythmia Service, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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Lehrer PM, Vaschillo E, Vaschillo B, Lu SE, Eckberg DL, Edelberg R, Shih WJ, Lin Y, Kuusela TA, Tahvanainen KUO, Hamer RM. Heart rate variability biofeedback increases baroreflex gain and peak expiratory flow. Psychosom Med 2003; 65:796-805. [PMID: 14508023 DOI: 10.1097/01.psy.0000089200.81962.19] [Citation(s) in RCA: 278] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE We evaluated heart rate variability biofeedback as a method for increasing vagal baroreflex gain and improving pulmonary function among 54 healthy adults. METHODS We compared 10 sessions of biofeedback training with an uninstructed control. Cognitive and physiological effects were measured in four of the sessions. RESULTS We found acute increases in low-frequency and total spectrum heart rate variability, and in vagal baroreflex gain, correlated with slow breathing during biofeedback periods. Increased baseline baroreflex gain also occurred across sessions in the biofeedback group, independent of respiratory changes, and peak expiratory flow increased in this group, independently of cardiovascular changes. Biofeedback was accompanied by fewer adverse relaxation side effects than the control condition. CONCLUSIONS Heart rate variability biofeedback had strong long-term influences on resting baroreflex gain and pulmonary function. It should be examined as a method for treating cardiovascular and pulmonary diseases. Also, this study demonstrates neuroplasticity of the baroreflex.
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Affiliation(s)
- Paul M Lehrer
- Department of Psychiatry Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
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Berman M, Ben-Gal T, Dvir D, Mansharov M, Kusniec J, Strasberg B, Sagie A, Sahar G, Eidelman L, Vidne B, Aravot D. Automatic implantable cardioverter defibrillator as "bridge to heart transplantation" for sudden death high-risk patients. Transplant Proc 2001; 33:2906-7. [PMID: 11543784 DOI: 10.1016/s0041-1345(01)02245-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- M Berman
- Heart-Lung Transplant Unit, Department of Cardiothoracic Surgery, Rabin Medical Center, Beilinson Campus, Sackler Faculty of Medicine, Tel Aviv University, Petach-Tikva, Israel
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Affiliation(s)
- W Arthur
- Cardiology Department, Castle Hill Hospital, Castle Road, Cottingham, East Yorkshire HU16 5JQ, UK
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Mizumaki K, Fujiki A, Usui M, Shimono M, Hayashi H, Nagasawa H, Inoue H. Changes in autonomic nervous activity after catheter ablation of right ventricular outflow tract tachycardia. JAPANESE CIRCULATION JOURNAL 1999; 63:697-703. [PMID: 10496485 DOI: 10.1253/jcj.63.697] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Idiopathic right ventricular outflow tract (RVOT) tachycardia is prone to occur when sympathetic nervous activity increases. The effects of catheter ablation on the arrhythmia may be modified by changes in the sympathovagal balance induced by the ablation. In 8 patients with RVOT tachycardia, analyses of heart rate variability (HRV) were performed before, early (1-3 days, POST1) and late (7-14 days, POST2) after the ablation. From 24-h ambulatory Holter monitoring, RR intervals of a 2-h period during sleep (00.00-06.00 h) were analyzed. MSSD and pNN50 were increased along with a decrease in the frequency of ventricular arrhythmias at both POST1 and POST2 after successful ablation. In contrast, high frequency power (HF) was increased, and low frequency power (LF) and LF/HF were decreased only at POST2 in the 8 patients. In 4 patients in whom the initial ablation had been unsuccessful, the indices of HRV did not change significantly after the unsuccessful ablation, but after successful ablation they changed as in the other 4 patients. After successful catheter ablation of the RVOT tachycardia, sympathetic nervous activity was decreased and parasympathetic nervous activity was increased along with decrease in the frequency of ventricular arrhythmias. The presence of ventricular tachyarrhythmia could, therefore, elicit sympathetic predominance and consequently modify arrhythmogenesis.
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Affiliation(s)
- K Mizumaki
- The Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan
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Abstract
In spite of recent advances in secondary prevention, sudden cardiac death has remained a major public health problem as the majority of fatalities occur in subjects without a history of severe heart disease. Abrupt rupture of a vulnerable plaque resulting in thrombotic occlusion of a coronary artery is a common cause of sudden death in this population. Coronary occlusion does not, however, invariably lead to sudden death but may cause acute myocardial infarction or exacerbation of chest pain. Extensive studies in experimental animals and increasing clinical evidence indicate that autonomic nervous activity has a significant role in modifying the clinical outcome. Sympathetic hyperactivity favours the genesis of life-threatening ventricular tachyarrhythmias while vagal activation exerts an antifibrillatory effect. Strong afferent stimuli from the ischaemic myocardium impair arterial baroreflex and may lead to dangerous haemodynamic instability. Studies with a human angioplasty model have shown that there is wide interindividual variation in the type and severity of autonomic reactions during the early phase of abrupt coronary occlusion, a critical period for out-of-hospital cardiac arrest. The site of the occlusion is not a significant determinant of the reactions, whereas the severity of a coronary stenosis, adaptation or ischaemic preconditioning, beta-blockade and gender seem to affect the autonomic reactions and occurrence of complex ventricular arrhythmias. Clinical and angiographic factors are, however, poor predictors of autonomic reactions in an individual patient. Recent studies have documented a hereditary component for autonomic function, and genetic factors may also modify the clinical manifestations of acute coronary occlusion.
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Airaksinen KE, Ikäheimo MJ, Linnaluoto M, Tahvanainen KU, Huikuri HV. Gender difference in autonomic and hemodynamic reactions to abrupt coronary occlusion. J Am Coll Cardiol 1998; 31:301-6. [PMID: 9462571 DOI: 10.1016/s0735-1097(97)00489-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES We sought to determine whether there are gender-related differences in autonomic and hemodynamic responses to abrupt coronary occlusion. BACKGROUND The risk of sudden death before hospital admission is higher in men with an acute myocardial infarction. The reasons for this gender-related difference are not well understood. Cardiovascular autonomic regulation modifies the outcome of acute coronary events, and there are gender differences in the autonomic regulation of heart rate (HR) in normal physiologic circumstances. METHODS We analyzed the changes in HR, HR variability and blood pressure and the occurrence of ventricular ectopic beats during a 2-min coronary occlusion in 140 men and 65 women referred for single-vessel coronary angioplasty. The ranges of nonspecific responses were determined by analyzing a control group of 19 patients with no ischemia during a 2-min balloon inflation in a totally occluded coronary artery. RESULTS Women more often had ST segment changes (p < 0.01) and chest pain (p < 0.05) during the occlusion. Significant bradycardia or increase in HR variability as a sign of vagal activation occurred more often in women than in men (31% vs. 13%, p < 0.01 and 25% vs. 11%, p < 0.05, respectively). Coronary occlusion also more often caused (28% vs. 11%, p < 0.01) a decrease in blood pressure in women. The most pronounced female preponderance was in the incidence of Bezold-Jarisch-type reaction (i.e., simultaneous bradycardia and decrease in blood pressure [16% vs. 0.7%, p < 0.0001]). Logistic regression models developed to analyze the significance of gender while controlling for baseline variables and signs of ischemia identified female gender to be an independent predictor of bradycardic reactions (odds ratio [OR] 3.2, 95% confidence interval [CI] 1.4 to 7.7, p < 0.01), hypotensive reactions (OR 2.6, 95% CI 1.1 to 6.0, p < 0.05) and Bezold-Jarisch-type response (OR 22.2, 95% CI 2.5 to 200, p < 0.01). Significance of female gender as a protector against early coronary occlusion-induced ventricular ectopic beats emerged as having borderline significance (OR 0.4, CI 0.1 to 1.1, p = 0.07). CONCLUSIONS Vagal activation is more common in women than in men during abrupt coronary occlusion and may have beneficial antiarrhythmic effects, modifying the outcome of acute coronary events.
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Affiliation(s)
- K E Airaksinen
- Department of Medicine, University of Oulu, Finland. kari.airaksinen@.oulu.fi
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Myerburg RJ, Interian A, Mitrani RM, Kessler KM, Castellanos A. Frequency of sudden cardiac death and profiles of risk. Am J Cardiol 1997; 80:10F-19F. [PMID: 9291445 DOI: 10.1016/s0002-9149(97)00477-3] [Citation(s) in RCA: 269] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The epidemiology of ventricular tachycardia/fibrillation (VT/VF) and sudden cardiac death (SCD) must be explored from multiple aspects, each of which contributes insights into the problem and no one of which exerts exclusive dominance for preventive or therapeutic strategies. These include: (1) population dynamics, using conventional epidemiologic approaches; (2) risk as a function of time from an index event; (3) conditioning risk factors, based on the presence of underlying disease states; (4) transient risk factors that are dynamic and trigger a potentially fatal event at a specific point in time; and (5) "response risk," which refers to individual susceptibility (possibly determined genetically) to the adverse effects of longitudinal and/or dynamic risk factors. Major inroads into profiling individual or population risk of SCD will require better understanding of each of these epidemiologic-clinical-physiologic interactions. The disciplines range from epidemiology, through clinical medicine, to membrane channel physiology, genetic determinants, and molecular biology.
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Affiliation(s)
- R J Myerburg
- Division of Cardiology, University of Miami School of Medicine, Jackson Memorial Hospital, and VA Medical Center, Florida 33101, USA
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19
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Abstract
The patient with syncope often poses a formidable diagnostic challenge. A large number of underlying causes must be considered, ranging in severity from benign to life-threatening. A careful, systematic clinical evaluation beginning with a history, physical examination, and ECG will establish the diagnosis in most patients, and the judicious use of specialized testing will confirm or uncover the cause in many of the remaining cases. Further basic and clinical research into the pathogenesis and treatment of neurocardiogenic syncope, the role of HUT testing in neurally mediated syncope, and the optimal use of EPS in patients with cardiac disease will markedly improve our management of these patients in the future.
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Affiliation(s)
- M C Henderson
- Division of General Medicine, University of Texas Health Science Center at San Antonio, USA
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20
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Sheldon R, Rose S, Koshman ML. Isoproterenol tilt-table testing in patients with syncope and structural heart disease. Am J Cardiol 1996; 78:700-3. [PMID: 8831414 DOI: 10.1016/s0002-9149(96)00403-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We studied 55 patients with syncope and structural heart disease using both tilt-table testing and electrophysiologic studies. Although sustained ventricular tachycardia was found in 21 of 55 patients (38%), and neuromediated syncope in 18 of 51 patients (35%), only 16% of patients with ventricular tachycardia had a positive tilt-table test.
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Affiliation(s)
- R Sheldon
- Cardiovascular Research Group, University of Calgary, Alberta, Canada
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21
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Airaksinen KE, Ikäheimo MJ, Niemelä MJ, Valkama JO, Peuhkurinen KJ, Huikuri HV. Effect of beta blockade on heart rate variability during vessel occlusion at the time of coronary angioplasty. Am J Cardiol 1996; 77:20-4. [PMID: 8540451 DOI: 10.1016/s0002-9149(97)89128-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Beta blockers modify cardiovascular neural regulation, which may contribute to their protective effect against sudden cardiac death. To evaluate the effects of beta blockade on cardiovascular autonomic reactions caused by acute coronary occlusion in humans, heart rate (HR) variability was analyzed in the time and frequency domains immediately before and during balloon occlusion of a coronary artery in 116 patients randomly assigned to either chronic beta-blocker therapy (beta-blocker group) or no beta blockade (control group) during elective 1-vessel coronary angioplasty. Coronary occlusion (mean 112 seconds) caused a significant increase in both the high- and low-frequency components of HR variability in the control group (n = 58), from 2.7 +/- 1.6 to 3.4 +/- 1.7 (logarithmic units, p < 0.001) and from 4.3 +/- 1.3 to 4.8 +/- 1.5 (p < 0.01), respectively, whereas in the beta-blocker group (n = 58), the high-frequency power did not change during occlusion, but the low-frequency power increased from 3.9 +/- 1.4 to 4.4 +/- 1.4 (p = 0.01). Changes in high- and low-frequency components and HR were related to the change in systolic blood pressure during occlusion in the beta-blocker group (r = 0.53, p < 0.001; r = 0.34, p < 0.05; and r = -0.41, p < 0.01, respectively), but not in the control group (r = -0.17, r = -0.14, and r = 0.24, respectively). Thus, beta blockade attenuates the initial vagal activation associated with acute coronary occlusion and seems to maintain baroreflex-mediated cardiovascular control. The maintained integrity of baroreflex regulation and the alleviation of extreme autonomic reactions during beta blockade may modify the clinical outcome of acute coronary occlusion in a beneficial way.
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22
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Saxon LA, Wiener I, DeLurgio DB, Natterson PD, Laks H, Drinkwater DC, Stevenson WG. Implantable defibrillators for high-risk patients with heart failure who are awaiting cardiac transplantation. Am Heart J 1995; 130:501-6. [PMID: 7661067 DOI: 10.1016/0002-8703(95)90358-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The objective of this study was to assess the operative risk and efficacy of implantable defibrillators for preventing sudden death in patients with heart failure awaiting transplantation. The average waiting time for elective cardiac transplantation is 6 months to 1 year. Sudden cardiac death is the major source of mortality in outpatients in stable condition awaiting cardiac transplantation. The efficacy of implantable defibrillator therapy in this population is not established. We analyzed the operative risk, time to appropriate shock, and sudden death in 15 patients determined to be at high risk of sudden death who were accepted onto the outpatient cardiac transplant waiting list. Nonfatal postoperative complications occurred in two (13%) subjects with epicardial defibrillating lead systems and in none with transvenous lead systems. Defibrillation energies were 16 +/- 2 J versus 24 +/- 2 J with epicardial and transvenous lead systems, respectively. Sudden death free survival until transplantation was 93%. Most of the patients (60%) had an appropriate shock during a mean follow-up of 11 +/- 12 months. The mean time to an appropriate shock was 3 +/- 3 months. Hospital readmission was required in three (20%) subjects to await transplantation on an urgent basis. However, two of these subjects had received appropriate shocks before readmission. In selected patients at high risk for sudden death while on the outpatient cardiac transplant waiting list, the operative risk is low and adequate defibrillation energies can be obtained to allow implantable defibrillator placement. Most subjects will have an appropriate shock as outpatients before transplantation, and sudden death free survival is excellent.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L A Saxon
- Department of Medicine, UCLA Medical Center 90024-1679, USA
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23
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Airaksinen KE, Ylitalo KV, Peuhkurinen KJ, Ikäheimo MJ, Huikuri HV. Heart rate variability during repeated arterial occlusion in coronary angioplasty. Am J Cardiol 1995; 75:877-81. [PMID: 7732993 DOI: 10.1016/s0002-9149(99)80679-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Acute coronary occlusion may cause severe autonomic reactions that can modify the clinical presentation of acute ischemic events. To evaluate whether adaptation in these autonomic reactions exists during repeated short coronary occlusions, heart rate (HR) and its variability in the time and frequency domains were analyzed in 70 patients with significant (50% to 95%) coronary artery stenosis immediately before and during 2 identical balloon occlusions of the vessel (mean 110 seconds). Reactions were compared with the range of nonspecific changes formed by analyzing a control group (n = 13) with no ischemia during balloon inflation in a totally occluded coronary artery. Thus, neither occlusion caused significant changes in HR or HR variability in 29 patients (41%). Vagal activation, as seen by an abnormal increase in HR variability or bradycardia, or both, was observed in 24 patients (34%). HR reactions in this group (p < 0.05) were significantly attenuated during the second occlusion. An opposite reaction (i.e., abnormal decrease in HR variability or tachycardia, or both) was observed in 17 patients (24%). A nonsignificant tendency for attenuation of the reactions was also seen in this group. Severity of chest pain, frequency of ST-segment shifts, or narrowing of pulse pressure were comparable during the 2 occlusions. Thus, a preceding short vessel occlusion-reperfusion cycle seems to attenuate autonomic HR reactions, especially vagal reactions, during subsequent coronary occlusion. Alleviation of extreme autonomic reactions may modify the clinical outcome of coronary occlusion in a beneficial way.
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24
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Kosinski D, Grubb BP, Temesy-Armos P. Pathophysiological aspects of neurocardiogenic syncope: current concepts and new perspectives. Pacing Clin Electrophysiol 1995; 18:716-24. [PMID: 7596855 DOI: 10.1111/j.1540-8159.1995.tb04666.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neurocardiogenic syncope is both a common and complex clinical disorder. Although recent research has clarified some of the pathophysiological mechanisms involved, much still remains either unknown or incompletely understood. Further investigation into this condition will not only enhance our knowledge of this and other related disorders, but will shed greater light on the influences of the brain and autonomic system on heart rate and blood pressure regulation and aid in our understanding of the complex interrelationships of neurocardiology.
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Affiliation(s)
- D Kosinski
- Department of Medicine, Medical College of Ohio, Toledo 43699, USA
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25
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Peuhkurinen KJ, Uusimaa PA, Ruskoaho H, Linnaluoto M, Huikuri H. Hemodynamic recovery, atrial natriuretic peptide, and catecholamines during simulated ventricular tachycardia: effects of ventriculoatrial conduction. Pacing Clin Electrophysiol 1995; 18:75-82. [PMID: 7700835 DOI: 10.1111/j.1540-8159.1995.tb02479.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ventriculoatrial (VA) sequence and neurohumoral responses may be important modulators of hemodynamic recovery during VT. We studied the effects of VA conduction on blood pressure recovery, and levels of atrial natriuretic peptide (ANP), epinephrine, and norepinephrine during simulated VT. After diagnostic coronary angiography, VT was simulated by rapid right ventricular pacing (150 beats/min, 3 mins) in a consecutive series of patients. Whenever the patients demonstrated VA dissociation during ventricular pacing, they were included in the study. After 10 minutes of recovery, a group of nine patients then underwent an additional VA pacing (150 beats/min, 3 mins, VA delay of 150 msec). Intra-arterial blood pressure was continuously monitored, and plasma ANP and catecholamine levels were measured before, during, and after both pacing protocols. The mean arterial pressures declined rapidly by 26% and 30% after initiation of ventricular and VA pacing, respectively. The blood pressure then gradually recovered, the hemodynamic recovery being better during VA pacing. Plasma ANP and catecholamine levels increased toward the end of both pacing periods. The observed increase in ANP concentration was more prominent during VA pacing than ventricular pacing (P < 0.001), whereas catecholamine levels increased similarly. The results show that during simulated VT hemodynamic recovery is partially dependent on VA sequence. The increases in circulating ANP and catecholamines occur too slowly to account for the rapid changes in blood pressures observed after initiation of simulated VT. Therefore, other mechanisms, such as reflex stimulation of the sympathoadrenergic nervous system, must be involved, too. ANP release increases when atrial contraction frequency increases, but the exact determinants for this release remain unknown.
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Affiliation(s)
- K J Peuhkurinen
- Department of Internal Medicine, Oulu University Central Hospital, Finland
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26
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Abstract
Patients with recurrent unexplained syncope may have cardioinhibitory and vasodepressor responses provokable with head-up tilt with or without exogenous beta-adrenergic stimulation. Although these responses are believed to be neurally mediated, the neural mechanisms involved are poorly understood. Numerous studies have documented peripheral vasodilation, hypotension, and bradycardia at the time of syncope and several case reports have shown sudden withdrawal of vasoconstrictor sympathetic neural outflow to skeletal muscle in human subjects. In cats and rats, a similar response can be provoked with hemorrhage and is prevented by interruption of cardiac vagal C-fiber afferents. In dogs, however, section of these fibers does not prevent the development of a vasodepressor response. The provocation of vasodepressor syncope during nitroprusside infusion in a heart transplant recipient with presumed ventricular denervation also suggests that cardiac afferent nerves may not be required for the development of vasodepressor responses in humans. Other potential mechanisms include release of endogenous opioids or nitric oxide that may inhibit sympathetic nerve firing, and primary central nervous system activation (as in partial seizures) that triggers cardioinhibitory and vasodepressor responses. This article reviews our current understanding of the mechanisms involved in the development of neurally mediated syncope.
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Affiliation(s)
- R F Rea
- Department of Medicine, University of Iowa, Iowa City 52242
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27
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Peuhkurinen KJ, Huikuri HV, Ruskoaho H, Takkunen JT. Blood pressure, plasma atrial natriuretic peptide and catecholamines during rapid ventricular pacing and effects of beta-adrenergic blockade in coronary artery disease. Am J Cardiol 1992; 69:35-9. [PMID: 1530902 DOI: 10.1016/0002-9149(92)90672-l] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To study neurohumoral control mechanisms of the hemodynamic response to ventricular tachycardia, arterial blood pressure, plasma atrial natriuretic peptide (ANP) and catecholamine levels were monitored during simulated ventricular tachycardia before and after administration of beta blockade. Tachycardia was simulated by ventricular pacing at 150 beats/min for 150 seconds in 9 patients without and 14 with angiographically demonstrable coronary artery disease (CAD). The effects of intravenous propranolol (0.15 mg/kg) were evaluated in 7 control subjects and in 13 patients with CAD. Arterial blood pressure decreased to its minimum within 5 seconds after onset of pacing in all patients, the decrease being 27 and 30% (p = not significant) in the groups without and with CAD, respectively. Propranolol did not affect the initial decline, but blunted subsequent recovery. The ANP baseline levels were similar in both groups, increasing by 60% (p less than 0.05) and 71% (p less than 0.02) in the groups without and with CAD, respectively, during ventricular pacing. After administration of propranolol the increase in ANP was 180% in both groups. Rapid ventricular pacing did not affect catecholamine levels before propranolol, but after propranolol norepinephrine increased by 71 (p less than 0.02) and 97% (p less than 0.01) in patients without and with CAD, respectively. There was a significant correlation (r = 0.53, p = 0.001) between pacing-induced ANP and norepinephrine changes, but changes in arterial blood pressure did not correlate with those in either of these hormones. Thus, beta-adrenergic blockade blunts blood pressure recovery during simulated ventricular tachycardia. However, this is partly counterbalanced by increased circulating norepinephrine levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K J Peuhkurinen
- Department of Internal Medicine, Oulu University Central Hospital, Finland
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28
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Beauregard LA, Volosin KJ, Waxman HL. Differentiation of arrhythmias by measurement of intracardiac pressures in man. Pacing Clin Electrophysiol 1991; 14:161-7. [PMID: 1706500 DOI: 10.1111/j.1540-8159.1991.tb05085.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Antitachycardia devices currently use sustained high rate, abrupt changes in cycle length, and probability density function to determine the onset of ventricular tachycardia. Hemodynamic changes occur with the onset of tachycardia and may provide a method of discriminating supraventricular from ventricular tachycardia. In this study, patients had atrial and ventricular pressures measured during rapid atrial and ventricular pacing. Right atrial pressure increased significantly with ventricular pacing but not with atrial pacing. Right ventricular pressures did not significantly differ with atrial or ventricular pacing. The change in atrial pressure compared to baseline was greater, with ventricular pacing compared to atrial pacing. Right ventricular pressure increased compared to baseline with atrial or ventricular pacing, but there was no significant difference between pacing modalities. Measurement of right atrial pressure might prove useful in discriminating supraventricular from ventricular tachycardia.
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Affiliation(s)
- L A Beauregard
- Division of Cardiology, UMDNJ/Robert Wood Johnson Medical School, Camden Cooper Hospital/University Medical Center 08103
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29
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Sharma AD, Purves P, Yee R, Klein G, Jablonsky G, Kostuk WJ. Hemodynamic effects of intravenous procainamide during ventricular tachycardia. Am Heart J 1990; 119:1034-41. [PMID: 2330861 DOI: 10.1016/s0002-8703(05)80232-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Radionuclide angiography was used to study the hemodynamic effects of intravenous procainamide during stable monomorphic ventricular tachycardia. In four patients studied without procainamide, the ejection fraction was 25% +/- 2.4% during normal sinus rhythm, dropped to 11.3% +/- 2.2% (p less than 0.05) at the onset of ventricular tachycardia, increased to 16.7% +/- 1.7% after remaining in ventricular tachycardia for 10 minutes, and returned to 25.3% +/- 3.7% in sinus rhythm. In the 10 study patients, ejection fraction dropped from 36% +/- 5.8% in sinus rhythm to 25% +/- 5.1% in ventricular tachycardia (p less than 0.2). Ejection fraction decreased further (23% +/- 5.0%) following low doses of procainamide (140 +/- 52 mg) despite cycle length prolongation (354 +/- 18 msec versus 373 +/- 21 msec, p less than 0.5). In 8 of 10 patients, there was a progressive increase in the ejection fraction (28.8% +/- 4.1%). Ventricular tachycardia onset also resulted in a decrease in cardiac output and end-diastolic and end-systolic volumes. Two patients who tolerated procainamide in sinus rhythm showed hemodynamic collapse secondary to procainamide during ventricular tachycardia. We conclude that in some patients hemodynamic intolerance to an antiarrhythmic drug may only become evident during ventricular tachycardia.
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Affiliation(s)
- A D Sharma
- Mercy General Hospital, Sacramento, Canada
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30
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Huikuri HV, Cox M, Interian A, Kessler KM, Glicksman F, Castellanos A, Myerburg RJ. Efficacy of intravenous propranolol for suppression of inducibility of ventricular tachyarrhythmias with different electrophysiologic characteristics in coronary artery disease. Am J Cardiol 1989; 64:1305-9. [PMID: 2589196 DOI: 10.1016/0002-9149(89)90572-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The efficacy of intravenous propranolol for suppression of inducibility of sustained ventricular tachyarrhythmias (VT) was studied in 24 patients who had failed greater than or equal to 1 membrane-active antiarrhythmic drug (mean 2.2 +/- 1.2 drugs/patient). The response to propranolol was compared in 13 patients who had only stable monomorphic VTs inducible at baseline and another 11 patients who had greater than or equal to 1 episode of electrically unstable VTs (polymorphic VT, ventricular flutter or ventricular fibrillation) at baseline. Seven patients (29%) became noninducible (responders) and 17 patients (71%) remained inducible to sustained VT (nonresponders) after propranolol. The basal heart rate was faster in responders than in nonresponders (101 +/- 14 vs 86 +/- 11 beats/min, p less than 0.01). The magnitude of heart rate reduction was also greater after propranolol in responders (from 101 +/- 14 to 80 +/- 9 beats/min, p less than 0.001) than in nonresponders (from 86 +/- 11 to 74 +/- 9 beats/min, p less than 0.01) (p less than 0.05 between the groups), despite equal plasma propranolol concentrations (84 +/- 50 vs 88 +/- 43 ng/ml, difference not significant). Seven of 11 patients (64%) who had greater than or equal to 1 episode of unstable VTs inducible at baseline responded to intravenous propranolol, whereas none of the patients with only stable monomorphic VTs became noninducible after beta blockade (p less than 0.001). Responders had shorter cycle length of inducible VTs than nonresponders (225 +/- 38 vs 302 +/- 66 ms, p less than 0.001). Thus, intravenous propranolol appears to be efficacious in suppressing fast, electrically unstable VTs, compared to monomorphic VTs with slower rates.
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Affiliation(s)
- H V Huikuri
- Division of Cardiology, University of Miami Medical School, Florida
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31
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Affiliation(s)
- R F Rea
- Department of Medicine, University of Iowa, Iowa City 52242
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