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Schmidt AS, Lauridsen KG, Torp P, Bach LF, Rickers H, Løfgren B. Maximum-fixed energy shocks for cardioverting atrial fibrillation. Eur Heart J 2021; 41:626-631. [PMID: 31504412 DOI: 10.1093/eurheartj/ehz585] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/10/2019] [Accepted: 07/30/2019] [Indexed: 11/14/2022] Open
Abstract
AIMS Direct-current cardioversion is one of the most commonly performed procedures in cardiology. Low-escalating energy shocks are common practice but the optimal energy selection is unknown. We compared maximum-fixed and low-escalating energy shocks for cardioverting atrial fibrillation. METHODS AND RESULTS In a single-centre, single-blinded, randomized trial, we allocated elective atrial fibrillation patients to cardioversion using maximum-fixed (360-360-360 J) or low-escalating (125-150-200 J) biphasic truncated exponential shocks. The primary endpoint was sinus rhythm 1 min after cardioversion. Safety endpoints were any arrhythmia, myocardial injury, skin burns, and patient-reported pain after cardioversion. We randomized 276 patients, and baseline characteristics were well-balanced between groups (mean ± standard deviation age: 68 ± 9 years, male: 72%, atrial fibrillation duration >1 year: 30%). Sinus rhythm 1 min after cardioversion was achieved in 114 of 129 patients (88%) in the maximum-fixed energy group, and in 97 of 147 patients (66%) in the low-escalating energy group (between-group difference; 22 percentage points, 95% confidence interval 13-32, P < 0.001). Sinus rhythm after first shock occurred in 97 of 129 patients (75%) in the maximum-fixed energy group compared to 50 of 147 patients (34%) in the low-escalating energy group (between-group difference; 41 percentage points, 95% confidence interval 30-51). There was no significant difference between groups in any safety endpoint. CONCLUSION Maximum-fixed energy shocks were more effective compared with low-escalating energy shocks for cardioverting atrial fibrillation. We found no difference in any safety endpoint.
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Affiliation(s)
- Anders S Schmidt
- Clinical Research Unit, Randers Regional Hospital, Skovlyvej 15, 8930 Randers NE, Denmark.,Department of Internal Medicine, Randers Regional Hospital, Skovlyvej 15, 8930 Randers NE, Denmark.,Research Center for Emergency Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 161, Aarhus N, Denmark
| | - Kasper G Lauridsen
- Clinical Research Unit, Randers Regional Hospital, Skovlyvej 15, 8930 Randers NE, Denmark.,Department of Internal Medicine, Randers Regional Hospital, Skovlyvej 15, 8930 Randers NE, Denmark.,Research Center for Emergency Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 161, Aarhus N, Denmark
| | - Peter Torp
- Department of Internal Medicine, Randers Regional Hospital, Skovlyvej 15, 8930 Randers NE, Denmark
| | - Leif F Bach
- Department of Anesthesiology, Randers Regional Hospital, Skovlyvej 15, 8930 Randers NE, Denmark
| | - Hans Rickers
- Department of Internal Medicine, Randers Regional Hospital, Skovlyvej 15, 8930 Randers NE, Denmark
| | - Bo Løfgren
- Department of Internal Medicine, Randers Regional Hospital, Skovlyvej 15, 8930 Randers NE, Denmark.,Research Center for Emergency Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 161, Aarhus N, Denmark.,Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark.,Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark
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2
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Chiou YA, Cheng LK, Lin SF. Effects of high-frequency biphasic shocks on ventricular vulnerability and defibrillation outcomes through synchronized virtual electrode responses. PLoS One 2020; 15:e0232529. [PMID: 32357163 PMCID: PMC7194403 DOI: 10.1371/journal.pone.0232529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/16/2020] [Indexed: 11/19/2022] Open
Abstract
Electrical defibrillation is a well-established treatment for cardiac dysrhythmias. Studies have suggested that shock-induced spatial sawtooth patterns and virtual electrodes are responsible for defibrillation efficacy. We hypothesize that high-frequency shocks enhance defibrillation efficacy by generating temporal sawtooth patterns and using rapid virtual electrodes synchronized with shock frequency. High-speed optical mapping was performed on isolated rat hearts at 2000 frames/s. Two defibrillation electrodes were placed on opposite sides of the ventricles. An S1-S2 pacing protocol was used to induce ventricular tachyarrhythmia (VTA). High-frequency shocks of equal energy but varying frequencies of 125–1000 Hz were used to evaluate VTA vulnerability and defibrillation success rate. The 1000-Hz shock had the highest VTA induction rate in the shorter S1-S2 intervals (50 and 100 ms) and the highest VTA defibrillation rate (70%) among all frequencies. Temporal sawtooth patterns and synchronous shock-induced virtual electrode responses could be observed with frequencies of up to 1000 Hz. The improved defibrillation outcome with high-frequency shocks suggests a lower energy requirement than that of low-frequency shocks for successful ventricular defibrillation.
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Affiliation(s)
- Yu-An Chiou
- Department of Electrical and Computer Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Li-Kuan Cheng
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Shien-Fong Lin
- Department of Electrical and Computer Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
- * E-mail:
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3
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Hayase J, Do DH, Boyle NG. Defibrillation Threshold Testing: Current Status. Arrhythm Electrophysiol Rev 2018; 7:288-293. [PMID: 30588318 DOI: 10.15420/aer.2018.54.2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/15/2018] [Indexed: 11/04/2022] Open
Abstract
When the transvenous ICD initially came into use for primary and secondary prevention of sudden cardiac death, defibrillation threshold (DFT) testing was universally performed. However, DFT testing is no longer routinely recommended for transvenous ICD implantation except in certain situations. Risk scores can help guide the decision to perform DFT testing. The subcutaneous ICD represents an area of uncertainty, with limited data available regarding the role of DFT testing in these devices. Current guidelines give a class I recommendation for performing DFT testing at the time of implant. Further studies are needed before this recommendation can be safely dismissed.
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Affiliation(s)
- Justin Hayase
- UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA Los Angeles, CA, USA
| | - Duc H Do
- UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA Los Angeles, CA, USA
| | - Noel G Boyle
- UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA Los Angeles, CA, USA
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4
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Do K, Chang P, Konecny T, Carlson SK, Tun H, Huntsinger M, Doshi RN. Predictors of Elevated Defibrillation Threshold with the Subcutaneous Implantable Cardioverter-defibrillator. J Innov Card Rhythm Manag 2017; 8:2920-2929. [PMID: 32494435 PMCID: PMC7252865 DOI: 10.19102/icrm.2017.081203] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/07/2017] [Indexed: 11/06/2022] Open
Abstract
There are limited data regarding defibrillation thresholds (DFTs) for the subcutaneous implantable cardioverter-defibrillator (S-ICD), and factors associated with elevated DFTs remain incompletely understood. The objective of this study was to determine the factors associated with elevated DFTs in patients undergoing S-ICD implantation. A retrospective cross-sectional analysis of all patients undergoing S-ICD implantation at our institution between 2013 and 2016 who underwent step-down DFT testing was performed. Factors associated with a higher DFT were analyzed. In total, 56 patients (mean age: 49.3 ± 13.1 years, mean left ventricular ejection rate: 31.1% ± 13.7%) underwent S-ICD implantation in the study period. Full DFT testing was performed in 31 of the 56 patients (55%), with an average DFT of 46.4 joules (J) ± 25.9 J found among this cohort. The DFT was > 65 J in five of the 31 patients (16%). A high DFT was associated with increased body mass index (BMI) (37.7 kg/m2 versus 29.4 kg/m2; p = 0.02) and either increased septal or posterior wall thickness (1.5 cm versus 1.0 cm; p = 0.0003 and 1.4 cm versus 1.1 cm; p= 0.003, respectively). Patients with high DFTs also had higher failed shock impedance values (138 Ω versus 71 Ω; p = 0.005). Renal failure did not appear to affect DFT (51.4 J versus 51.7 J; p = 0.99). BMI, body surface area (BSA), and septal and posterior left ventricular wall thickness predicted elevated DFT on univariate analysis, although findings were not significant with multivariate analysis due to the small sample size. Thus, elevated S-ICD DFT appears to be associated with increased BMI, BSA, and septal or posterior wall thickness. In contrast, dialysis-dependent renal failure is not associated with elevated DFT. Further investigation is necessary in order to better characterize and predict which patients are at-risk for high DFTs.
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Affiliation(s)
- Khuyen Do
- Keck USC Medical Center and LAC-USC Medical Center, Keck School of Medicine of USC, Los Angeles, California, USA
| | - Philip Chang
- Keck USC Medical Center and LAC-USC Medical Center, Keck School of Medicine of USC, Los Angeles, California, USA
| | - Tomas Konecny
- Keck USC Medical Center and LAC-USC Medical Center, Keck School of Medicine of USC, Los Angeles, California, USA
| | - Steven K Carlson
- Keck USC Medical Center and LAC-USC Medical Center, Keck School of Medicine of USC, Los Angeles, California, USA
| | - Han Tun
- Keck USC Medical Center and LAC-USC Medical Center, Keck School of Medicine of USC, Los Angeles, California, USA
| | - Mary Huntsinger
- Keck USC Medical Center and LAC-USC Medical Center, Keck School of Medicine of USC, Los Angeles, California, USA
| | - Rahul N Doshi
- Keck USC Medical Center and LAC-USC Medical Center, Keck School of Medicine of USC, Los Angeles, California, USA
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5
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Burri H, Moretti F, Meyer P. Low-energy cardioversion of ventricular tachycardia: When less is more. Indian Pacing Electrophysiol J 2017; 17:44-47. [PMID: 29072992 PMCID: PMC5405749 DOI: 10.1016/j.ipej.2017.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 02/13/2017] [Indexed: 11/23/2022] Open
Abstract
Herein we report the case of a patient who was admitted in ventricular tachycardia after having received multiple ineffective (and sometimes pro-arrhythmic) high-energy internal shocks from his ICD and who was finally successfully treated by a commanded low-energy internal cardioversion of 0.6 J. This article revisits the use of low-energy shocks and discusses their electrophysiogical mechanisms and clinical implications.
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Affiliation(s)
- Haran Burri
- Cardiology Department, Geneva University Hospital, Geneva, Switzerland.
| | - Francesco Moretti
- Cardiology Department, Geneva University Hospital, Geneva, Switzerland
| | - Philippe Meyer
- Cardiology Department, Geneva University Hospital, Geneva, Switzerland
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6
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Defibrillation Threshold Testing: Who Doesn't Get It? Card Electrophysiol Clin 2016; 4:135-41. [PMID: 26939810 DOI: 10.1016/j.ccep.2012.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Defibrillation testing has been routinely performed as part of the implantable cardioverter-defibrillator (ICD) implantation procedure, and is currently supported by practice guidelines; however, more recently, this practice has been called into question. Such testing is safe, and serious complications are rare. With modern ICD systems, physicians will rarely encounter a patient in whom defibrillation will fail. This article reviews the literature regarding the utility, necessity, complications, and cost of routine operative and follow-up defibrillation testing, and, it is hoped, clarifies the issue of "Who doesn't get it?"
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7
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Ruetz LL, Koehler JL, Brown ML, Jackson TE, Belk P, Swerdlow CD. Sinus rhythm R-wave amplitude as a predictor of ventricular fibrillation undersensing in patients with implantable cardioverter-defibrillator. Heart Rhythm 2015; 12:2411-8. [PMID: 26272520 DOI: 10.1016/j.hrthm.2015.08.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Ventricular fibrillation (VF) is induced during implantable cardioverter-defibrillator (ICD) implantation to ensure that the ICD will sense, detect, and defibrillate VF. ICD implant guidelines state that the amplitude of the sinus rhythm R wave recorded from the ventricular electrogram should have amplitude ≥5 mV. No study has tested the relationship between sinus rhythm R-wave amplitude and VF sensing using modern, transvenous sensing electrodes. OBJECTIVE The goal of this study was to determine whether there is a sinus rhythm R-wave amplitude cutoff that can be used to determine which patients are not at risk of VF undersensing. METHODS A retrospective analysis of induced and spontaneous VF episodes from 2 clinical trials with 2022 patients was performed. Episodes with undersensing during the initial detection of VF were identified, and the distribution of sinus rhythm R-wave amplitudes for patients with and without VF undersensing was analyzed. RESULTS Only 3% of analyzed induced VF episodes were considered to have VF undersensing, and none had clinically significant detection delays. There was no correlation between device-measured, rectified sinus rhythm R-wave amplitude and VF undersensing at the time of implantation or during follow-up, although <4% of patients had sinus rhythm R-waves with amplitude <3 mV. CONCLUSION We analyzed true bipolar sensing of induced VF or spontaneous ventricular tachycardia/VF detected in the ICD VF zone. Sensing of VF was so reliable that clinically significant undersensing did not occur. Our findings do not support any recommended minimum sinus rhythm R wave to ensure reliable sensing of VF or the necessity of inducing VF to verify sensing for rectified sinus rhythm R-waves with amplitude ≥3 mV.
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Affiliation(s)
| | | | | | | | - Paul Belk
- Medtronic, Inc., Minneapolis, Minnesota
| | - Charles D Swerdlow
- Cedars-Sinai Heart Institute; David Geffen School of Medicine at UCLA, Los Angeles, California
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8
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Kroll MW, Perkins PE, Panescu D. Electric fence standards comport with human data and AC limits. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2015:1343-1348. [PMID: 26736517 DOI: 10.1109/embc.2015.7318617] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
INTRODUCTION The ubiquitous electric fence is essential to modern agriculture and has saved lives by reducing the number of livestock automobile collisions. Modern safety standards such as IEC 60335-2-76 and UL 69 have played a role in this positive result. However, these standards are essentially based on energy and power (RMS current), which have limited direct relationship to cardiac effects. We compared these standards to bioelectrically more relevant units of charge and average current in view of recent work on VF (ventricular fibrillation) induction and to existing IEC AC current limits. METHODS AND RESULTS There are 3 limits for normal (low) pulsing rate: IEC energy limit, IEC current limit, and UL current limit. We then calculated the delivered charge allowed for each pulse duration for these limits and then compared them to a charge-based safety model derived from published human ventricular-fibrillation induction data. Both the IEC and UL also allow for rapid pulsing for up to 3 minutes. We calculated maximum outputs for various pulse durations assuming pulsing at 10, 20, and 30 pulses per second. These were then compared to standard utility power safety (AC) limits via the conversion factor of 7.4 to convert average current to RMS current for VF risk. The outputs of TASER electrical weapons (typically < 100 μC and ~100 μs duration) were also compared. CONCLUSIONS The IEC and UL electric fence energizer normal rate standards are conservative in comparison with actual human laboratory experiments. The IEC and UL electric fence energizer rapid-pulsing standards are consistent with accepted IEC AC current limits for commercially used pulse durations.
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9
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Phan K, Kabunga P, Kilborn MJ, Sy RW. Defibrillator Threshold Testing at Generator Replacement: Is it Time to Abandon the Practice? PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2015; 38:777-81. [PMID: 25790073 DOI: 10.1111/pace.12630] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/09/2015] [Accepted: 03/12/2015] [Indexed: 01/29/2023]
Affiliation(s)
- Kevin Phan
- Sydney Medical School, University of Sydney, Sydney, Australia
| | - Peter Kabunga
- Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Michael J Kilborn
- Sydney Medical School, University of Sydney, Sydney, Australia.,Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Raymond W Sy
- Sydney Medical School, University of Sydney, Sydney, Australia.,Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia
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10
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Healey JS, Hohnloser SH, Glikson M, Neuzner J, Mabo P, Vinolas X, Kautzner J, O'Hara G, VanErven L, Gadler F, Pogue J, Appl U, Gilkerson J, Pochet T, Stein KM, Merkely B, Chrolavicius S, Meeks B, Foldesi C, Thibault B, Connolly SJ. Cardioverter defibrillator implantation without induction of ventricular fibrillation: a single-blind, non-inferiority, randomised controlled trial (SIMPLE). Lancet 2015; 385:785-91. [PMID: 25715991 DOI: 10.1016/s0140-6736(14)61903-6] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Defibrillation testing by induction and termination of ventricular fibrillation is widely done at the time of implantation of implantable cardioverter defibrillators (ICDs). We aimed to compare the efficacy and safety of ICD implantation without defibrillation testing versus the standard of ICD implantation with defibrillation testing. METHODS In this single-blind, randomised, multicentre, non-inferiority trial (Shockless IMPLant Evaluation [SIMPLE]), we recruited patients aged older than 18 years receiving their first ICD for standard indications at 85 hospitals in 18 countries worldwide. Exclusion criteria included pregnancy, awaiting transplantation, particpation in another randomised trial, unavailability for follow-up, or if it was expected that the ICD would have to be implanted on the right-hand side of the chest. Patients undergoing initial implantation of a Boston Scientific ICD were randomly assigned (1:1) using a computer-generated sequence to have either defibrillation testing (testing group) or not (no-testing group). We used random block sizes to conceal treatment allocation from the patients, and randomisation was stratified by clinical centre. Our primary efficacy analysis tested the intention-to-treat population for non-inferiority of no-testing versus testing by use of a composite outcome of arrhythmic death or failed appropriate shock (ie, a shock that did not terminate a spontaneous episode of ventricular tachycardia or fibrillation). The non-inferiority margin was a hazard ratio (HR) of 1·5 calculated from a proportional hazards model with no-testing versus testing as the only covariate; if the upper bound of the 95% CI was less than 1·5, we concluded that ICD insertion without testing was non-inferior to ICD with testing. We examined safety with two, 30 day, adverse event outcome clusters. The trial is registered with ClinicalTrials.gov, number NCT00800384. FINDINGS Between Jan 13, 2009, and April 4, 2011, of 2500 eligible patients, 1253 were randomly assigned to defibrillation testing and 1247 to no-testing, and followed up for a mean of 3·1 years (SD 1·0). The primary outcome of arrhythmic death or failed appropriate shock occurred in fewer patients (90 [7% per year]) in the no-testing group than patients who did receive it (104 [8% per year]; HR 0·86, 95% CI 0·65-1·14; pnon-inferiority <0·0001). The first safety composite outcome occurred in 69 (5·6%) of 1236 patients with no-testing and in 81 (6·5%) of 1242 patients with defibrillation testing, p=0·33. The second, pre-specified safety composite outcome, which included only events most likely to be directly caused by testing, occurred in 3·2% of patients with no-testing and in 4·5% with defibrillation testing, p=0·08. Heart failure needing intravenous treatment with inotropes or diuretics was the most common adverse event (in 20 [2%] of 1236 patients in the no-testing group vs 28 [2%] of 1242 patients in the testing group, p=0·25). INTERPRETATION Routine defibrillation testing at the time of ICD implantation is generally well tolerated, but does not improve shock efficacy or reduce arrhythmic death. FUNDING Boston Scientific and the Heart and Stroke Foundation (Ontario Provincial office).
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Affiliation(s)
- Jeff S Healey
- Population Health Research Institute, McMaster University, Hamilton, ON, Canada.
| | | | - Michael Glikson
- Leviev Heart Center, Sheba Medical Center, Tel Hashomer, Israel
| | | | | | | | - Josef Kautzner
- Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Gilles O'Hara
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, QC, Canada
| | | | | | - Janice Pogue
- Population Health Research Institute, McMaster University, Hamilton, ON, Canada
| | - Ursula Appl
- Boston Scientific, Minneapolis MN, USA, and Brussels, Belgium
| | - Jim Gilkerson
- Boston Scientific, Minneapolis MN, USA, and Brussels, Belgium
| | - Thierry Pochet
- Boston Scientific, Minneapolis MN, USA, and Brussels, Belgium
| | - Kenneth M Stein
- Boston Scientific, Minneapolis MN, USA, and Brussels, Belgium
| | - Bela Merkely
- Semmelweis University, Heart and Vascular Centre, Budapest, Hungary
| | - Susan Chrolavicius
- Population Health Research Institute, McMaster University, Hamilton, ON, Canada
| | - Brandi Meeks
- Population Health Research Institute, McMaster University, Hamilton, ON, Canada
| | - Csaba Foldesi
- Gottsegen National Institute of Cardiology, Budapest, Hungary
| | | | - Stuart J Connolly
- Population Health Research Institute, McMaster University, Hamilton, ON, Canada
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Ventricular fibrillation: are swine a sensitive species? J Interv Card Electrophysiol 2015; 42:83-9. [DOI: 10.1007/s10840-014-9964-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 12/05/2014] [Indexed: 10/24/2022]
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12
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Khairy P, Van Hare GF, Balaji S, Berul CI, Cecchin F, Cohen MI, Daniels CJ, Deal BJ, Dearani JA, Groot ND, Dubin AM, Harris L, Janousek J, Kanter RJ, Karpawich PP, Perry JC, Seslar SP, Shah MJ, Silka MJ, Triedman JK, Walsh EP, Warnes CA. PACES/HRS expert consensus statement on the recognition and management of arrhythmias in adult congenital heart disease: developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology (ACC), the American Heart Association (AHA), the European Heart Rhythm Association (EHRA), the Canadian Heart Rhythm Society (CHRS), and the International Society for Adult Congenital Heart Disease (ISACHD). Can J Cardiol 2014; 30:e1-e63. [PMID: 25262867 DOI: 10.1016/j.cjca.2014.09.002] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Healey JS, Brambatti M. Is defibrillation testing necessary for implantable transvenous defibrillators?: defibrillation testing should not be routinely performed at the time of implantable cardioverter defibrillator implantation. Circ Arrhythm Electrophysiol 2014; 7:347-51. [PMID: 24736424 DOI: 10.1161/circep.113.000373] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Jeff S Healey
- Population Health Research Institute, McMaster University, Hamilton, Canada
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14
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Khairy P, Van Hare GF, Balaji S, Berul CI, Cecchin F, Cohen MI, Daniels CJ, Deal BJ, Dearani JA, Groot ND, Dubin AM, Harris L, Janousek J, Kanter RJ, Karpawich PP, Perry JC, Seslar SP, Shah MJ, Silka MJ, Triedman JK, Walsh EP, Warnes CA. PACES/HRS Expert Consensus Statement on the Recognition and Management of Arrhythmias in Adult Congenital Heart Disease: developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology (ACC), the American Heart Association (AHA), the European Heart Rhythm Association (EHRA), the Canadian Heart Rhythm Society (CHRS), and the International Society for Adult Congenital Heart Disease (ISACHD). Heart Rhythm 2014; 11:e102-65. [PMID: 24814377 DOI: 10.1016/j.hrthm.2014.05.009] [Citation(s) in RCA: 371] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Indexed: 02/07/2023]
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How to Manage a High Defibrillation Threshold in ICD Patients: and Does it Really Matter? CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2013; 15:497-505. [DOI: 10.1007/s11936-013-0244-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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16
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GAN TIANYI, CAO XIAOZHI, YU ZHANG, TANG BAOPENG, LI JINXIN, XU GUOJUN, ZHOU XIANHUI, ZHANG YANYI, LI YAODONG, ZHANG JIANGHUA. Intraoperative defibrillation threshold testing and postoperative long-term efficacy of cardioverter-defibrillator implantation. Exp Ther Med 2013; 5:323-327. [PMID: 23251292 PMCID: PMC3524161 DOI: 10.3892/etm.2012.797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 10/18/2012] [Indexed: 12/02/2022] Open
Abstract
The aim of this study was to determine the defibrillation threshold (DFT) of implantable cardioverter-defibrillators (ICDs) and outcomes of treatment. Sixty-four patients received cardioverter-defibrillator implantation. During implantation, the DFT was determined by the defibrillation safety margin (DSM). All patients were followed up for 12–48 months after the implantation. The overall DFT was 14.27±2.56 J and the DSM was 18.40±1.89 J. Malignant ventricular arrhythmias occurred in 42 patients following cardioverter-defibrillator implantation including 500 episodes of non-sustained ventricular tachycardia (VT) and 289 episodes of persistent VT. VT was treated using antitachycardia pacing (ATP); 265 episodes were treated successfully by a single ATP treatment (91.69%) and 12 episodes were treated successfully by two ATP treatments (4.15%). Twelve episodes were converted by low-energy electrical cardioversion (4.15%). A total of 175 ventricular fibrillation (VF) episodes were identified, of which 18 episodes automatically terminated prior to treatment. In total, 146 episodes were converted by a single cardioversion with a defibrillation energy of 13.21±2.58 J and 11 episodes were converted by two cardioversions with a defibrillation energy of 16.19±2.48 J. It is safe and feasible to determine the DFT by DSM measurement during cardioverterdefibrillator implantation.
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Singh HR, Batra AS, Balaji S. Cardiac pacing and defibrillation in children and young adults. Indian Pacing Electrophysiol J 2013; 13:4-13. [PMID: 23329870 PMCID: PMC3539397 DOI: 10.1016/s0972-6292(16)30584-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The population of children and young adults requiring a cardiac pacing device has been consistently increasing. The current generation of devices are small with a longer battery life, programming capabilities that can cater to the demands of the young patients and ability to treat brady and tachyarrhythmias as well as heart failure. This has increased the scope and clinical indications of using these devices. As patients with congenital heart disease (CHD) comprise majority of these patients requiring devices, the knowledge of indications, pacing leads and devices, anatomical variations and the technical skills required are different than that required in the adult population. In this review we attempt to discuss these specific points in detail to improve the understanding of cardiac pacing in children and young adults.
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Affiliation(s)
- Harinder R Singh
- The Carman and Ann Adams Department of Pediatrics, Children's Hospital of Michigan
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Birgersdotter-Green U, Ruetz LL, Anand K, Monir G, Abeyratne AI, Bailey JR, Shorofsky SR, Hsia HH, Friedman PA. Automated Vulnerability Testing Identifies Patients With Inadequate Defibrillation Safety Margin. Circ Arrhythm Electrophysiol 2012; 5:1073-80. [DOI: 10.1161/circep.112.971275] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ulrika Birgersdotter-Green
- From the University of California San Diego, San Diego, CA (U.B-G., K.A.); Medtronic, Inc, Minneapolis, MN (L.L.R., A.I.A.); Florida Hospital Cardiovascular Institute, Orlando, FL (G.M.); Mid-Carolina Cardiology, Charlotte, NC (J.R.B.); University of Maryland Medical Center, Baltimore MD (S.R.S.); Stanford University, Stanford, CA (H.H.H.); and Mayo Clinic, Rochester, MN (P.A.F.)
| | - Linda L. Ruetz
- From the University of California San Diego, San Diego, CA (U.B-G., K.A.); Medtronic, Inc, Minneapolis, MN (L.L.R., A.I.A.); Florida Hospital Cardiovascular Institute, Orlando, FL (G.M.); Mid-Carolina Cardiology, Charlotte, NC (J.R.B.); University of Maryland Medical Center, Baltimore MD (S.R.S.); Stanford University, Stanford, CA (H.H.H.); and Mayo Clinic, Rochester, MN (P.A.F.)
| | - Kishlay Anand
- From the University of California San Diego, San Diego, CA (U.B-G., K.A.); Medtronic, Inc, Minneapolis, MN (L.L.R., A.I.A.); Florida Hospital Cardiovascular Institute, Orlando, FL (G.M.); Mid-Carolina Cardiology, Charlotte, NC (J.R.B.); University of Maryland Medical Center, Baltimore MD (S.R.S.); Stanford University, Stanford, CA (H.H.H.); and Mayo Clinic, Rochester, MN (P.A.F.)
| | - George Monir
- From the University of California San Diego, San Diego, CA (U.B-G., K.A.); Medtronic, Inc, Minneapolis, MN (L.L.R., A.I.A.); Florida Hospital Cardiovascular Institute, Orlando, FL (G.M.); Mid-Carolina Cardiology, Charlotte, NC (J.R.B.); University of Maryland Medical Center, Baltimore MD (S.R.S.); Stanford University, Stanford, CA (H.H.H.); and Mayo Clinic, Rochester, MN (P.A.F.)
| | - Athula I. Abeyratne
- From the University of California San Diego, San Diego, CA (U.B-G., K.A.); Medtronic, Inc, Minneapolis, MN (L.L.R., A.I.A.); Florida Hospital Cardiovascular Institute, Orlando, FL (G.M.); Mid-Carolina Cardiology, Charlotte, NC (J.R.B.); University of Maryland Medical Center, Baltimore MD (S.R.S.); Stanford University, Stanford, CA (H.H.H.); and Mayo Clinic, Rochester, MN (P.A.F.)
| | - J. Russell Bailey
- From the University of California San Diego, San Diego, CA (U.B-G., K.A.); Medtronic, Inc, Minneapolis, MN (L.L.R., A.I.A.); Florida Hospital Cardiovascular Institute, Orlando, FL (G.M.); Mid-Carolina Cardiology, Charlotte, NC (J.R.B.); University of Maryland Medical Center, Baltimore MD (S.R.S.); Stanford University, Stanford, CA (H.H.H.); and Mayo Clinic, Rochester, MN (P.A.F.)
| | - Stephen R. Shorofsky
- From the University of California San Diego, San Diego, CA (U.B-G., K.A.); Medtronic, Inc, Minneapolis, MN (L.L.R., A.I.A.); Florida Hospital Cardiovascular Institute, Orlando, FL (G.M.); Mid-Carolina Cardiology, Charlotte, NC (J.R.B.); University of Maryland Medical Center, Baltimore MD (S.R.S.); Stanford University, Stanford, CA (H.H.H.); and Mayo Clinic, Rochester, MN (P.A.F.)
| | - Henry H. Hsia
- From the University of California San Diego, San Diego, CA (U.B-G., K.A.); Medtronic, Inc, Minneapolis, MN (L.L.R., A.I.A.); Florida Hospital Cardiovascular Institute, Orlando, FL (G.M.); Mid-Carolina Cardiology, Charlotte, NC (J.R.B.); University of Maryland Medical Center, Baltimore MD (S.R.S.); Stanford University, Stanford, CA (H.H.H.); and Mayo Clinic, Rochester, MN (P.A.F.)
| | - Paul A. Friedman
- From the University of California San Diego, San Diego, CA (U.B-G., K.A.); Medtronic, Inc, Minneapolis, MN (L.L.R., A.I.A.); Florida Hospital Cardiovascular Institute, Orlando, FL (G.M.); Mid-Carolina Cardiology, Charlotte, NC (J.R.B.); University of Maryland Medical Center, Baltimore MD (S.R.S.); Stanford University, Stanford, CA (H.H.H.); and Mayo Clinic, Rochester, MN (P.A.F.)
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Healey JS, Hohnloser SH, Glikson M, Neuzner J, Viñolas X, Mabo P, Kautzner J, O'Hara G, Van Erven L, Gadler F, Appl U, Connolly SJ. The rationale and design of the Shockless IMPLant Evaluation (SIMPLE) trial: a randomized, controlled trial of defibrillation testing at the time of defibrillator implantation. Am Heart J 2012; 164:146-52. [PMID: 22877799 DOI: 10.1016/j.ahj.2012.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 05/06/2012] [Indexed: 10/28/2022]
Abstract
Defibrillation testing (DT) has been an integral part of defibrillator (implantable cardioverter defibrillator [ICD]) implantation; however, there is little evidence that it improves outcomes. Surveys show a trend toward ICD implantation without DT, which now exceeds 30% to 60% in some regions. Because there is no evidence to support dramatic shift in practice, a randomized trial is urgently needed. The SIMPLE trial will determine if ICD implantation without any DT is noninferior to implantation with DT. Patients will be eligible if they are receiving their first ICD using a Boston Scientific device (Boston Scientific, Natick, MA). Patients will be randomized to DT or no DT at the time of ICD implantation. In the DT arm, physicians will make all reasonable efforts to ensure 1 successful intraoperative defibrillation at 17 J or 2 at 21 J. The first clinical shock in all tachycardia zones will be set to 31 J for all patients. The primary outcome of SIMPLE will be the composite of ineffective appropriate shock or arrhythmic death. The safety outcome of SIMPLE will include a composite of potentially DT-related procedural complications within 30 days of ICD implantation. Several secondary outcomes will be evaluated, including all-cause mortality and heart failure hospitalization. Enrollment of 2,500 patients with 3.5-year mean follow-up will provide sufficient statistical power to demonstrate noninferiority. The study is being performed at approximately 90 centers in Canada, Europe, Israel, and Asia Pacific with final results expected in 2013.
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Pariaut R, Saelinger C, Vila J, Deforge W, Queiroz-Williams P, Beaufrère H, Zimmerman M, Saile K, Reynolds CA. Evaluation of shock waveform configuration on the defibrillation capacity of implantable cardioverter defibrillators in dogs. J Vet Cardiol 2012; 14:389-98. [PMID: 22819488 DOI: 10.1016/j.jvc.2012.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 05/16/2012] [Accepted: 05/18/2012] [Indexed: 11/25/2022]
Abstract
BACKGROUND Implantable cardioverter defibrillators (ICD) are programmed to detect ventricular arrhythmias and terminate them by delivering an electrical shock. A defibrillation threshold (DFT) at least 10 J below the maximum device output is recommended for successful therapy. Shock waveform configuration is a programmable parameter used to achieve a low DFT. It is hypothesized that a fixed-pulse configuration results in lower defibrillation energy requirements than a fixed-tilt configuration. ANIMALS 10 mongrel dogs. MATERIALS AND METHODS ICD generator and transvenous lead were surgically implanted. Defibrillation threshold was determined using a protocol guided by the upper limit of vulnerability. Fixed-pulse and fixed-tilt (50%/50%) waveform configurations were tested in a random order. Plasma cardiac troponin I (cTnI) was measured for signs of myocardial injury. RESULTS The experiment was completed in 9 dogs. Overall mean DFT value was 424 ± 88 V (9.2 ± 3.9 J). Mean differences among voltage, energy and impedance at the DFT for fixed-pulse (422 ± 97 V, 9.1 ± 4.2 J, 62.6 ± 13.8 Ω) and fixed-tilt (426 ± 83 V, 9.3 ± 3.8 J, 62.8 ± 18.5 Ω) configurations were not statistically significant (All P > 0.21). Cardiac TnI concentration changed from 0.03 ng/mL (95% CI: 0.02-0.04) at baseline to 0.11 ng/mL (95 CI: 0.08-0.16) after DFT was obtained with the first waveform configuration and 0.19 ng/mL (95% CI: 0.13-0.28) at the end of the study period. There were no significant changes in heart rate, end-tidal CO2 and blood pressure over time (all P > 0.09). CONCLUSION The tested ICD device and lead placement reliably produced acceptable DFT values, based on a 10-J safety margin below the maximum device output. A benefit of fixed-pulse configuration could not be demonstrated over the standard fixed-tilt waveform. Signs of acute myocardial damage from repeated high-voltage shocks and episodes of ventricular fibrillation seemed of limited clinical significance.
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Affiliation(s)
- Romain Pariaut
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
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Michowitz Y, Lellouche N, Contractor T, Bourke T, Wiener I, Buch E, Boyle N, Bersohn M, Shivkumar K. Defibrillation threshold testing fails to show clinical benefit during long-term follow-up of patients undergoing cardiac resynchronization therapy defibrillator implantation. Europace 2011; 13:683-8. [PMID: 21252192 DOI: 10.1093/europace/euq519] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The utility of defibrillation threshold testing in patients undergoing implantable cardioverter-defibrillator (ICD) implantation is controversial. Higher defibrillation thresholds have been noted in patients undergoing implantation of cardiac resynchronization therapy defibrillators (CRT-D). Since the risks and potential benefits of testing may be higher in this population, we sought to assess the impact of defibrillation safety margin or vulnerability safety margin testing in CRT-D recipients. METHODS AND RESULTS A total of 256 consecutive subjects who underwent CRT-D implantation between January 2003 and December 2007 were retrospectively reviewed. Subjects were divided into two groups based on whether (n= 204) or not (n= 52) safety margin testing was performed. Patient characteristics, tachyarrhythmia therapies, procedural results, and clinical outcomes were recorded. Baseline characteristics, including heart failure (HF) severity, were comparable between the groups. Four cases of HF exacerbation (2%), including one leading to one death, were recorded in the tested group immediately post-implantation. No complications were observed in the untested group. After a mean follow-up of 32 ± 20 months, the proportion of appropriate shocks in the two groups was similar (31 vs. 25%, P = 0.49). There were three cases of failed appropriate shocks in the tested group, despite adequate safety margins at implantation, whereas no failed shocks were noted in the untested group. Survival was similar in the two groups. CONCLUSION Defibrillation efficacy testing during implant of CRT-D was associated with increased morbidity and did not predict the success of future device therapy or improve survival during long-term follow-up.
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Affiliation(s)
- Yoav Michowitz
- UCLA Cardiac Arrhythmia Center, Ronald Reagan UCLA Medical Center, Los Angeles, CA 90095, USA.
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HEALEY JS, BIRNIE DH, LEE DS, Krahn AD, Crystal E, Simpson CS, Dorian P, Chen Z, Cameron D, Verma A, Connolly SJ, Gula LJ, Lockwood E, Nair G, Tu JV. Defibrillation Testing at the Time of ICD Insertion: An Analysis From the Ontario ICD Registry. J Cardiovasc Electrophysiol 2010; 21:1344-8. [DOI: 10.1111/j.1540-8167.2010.01850.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Weiss SM, Saint DA. The persistent sodium current blocker riluzole is antiarrhythmic and anti-ischaemic in a pig model of acute myocardial infarction. PLoS One 2010; 5:e14103. [PMID: 21124787 PMCID: PMC2991348 DOI: 10.1371/journal.pone.0014103] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 11/03/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The potential of the cardiac persistent sodium current as a target for protection of the myocardium from ischaemia and reperfusion injury is gaining increasing interest. We have investigated the anti-ischaemic and antiarrhythmic effects of riluzole, a selective INaP blocker, in an open chest pig model of infarction. METHODS AND PRINCIPAL FINDINGS The left anterior descending coronary artery (LAD) was ligated in 27 anesthetised pigs (landrace or large white, either sex, 20-35 kg) which had received riluzole (8 mg/kg IP; n = 6), lidocaine (2.5-12 mg/kg bolus plus 0.05-0.24 mg/kg/min; n = 11) or vehicle (n = 10) 50 min prior. Arrhythmias could be delineated into phase 1a (0 to 20 min), phase 1b (20 to 50 min) and phase 2 (from 50 min to termination at 180 min) and were classified as premature ventricular contractions (PVCs), non-sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) (spontaneously reverting within 15 s) or sustained VT or VF (ie. requiring cardioversion at 15 s). Riluzole reduced the average number of all arrhythmias in Phase 2 (PVCs from 484+/-119 to 32+/-13; non sustained arrhythmias from 8.9+/-4.4 to 0.7+/-0.5; sustained arrhythmias from 3.9+/-2.2 to 0.5+/-0.4); lidocaine reduced the average number of non-sustained and sustained arrhythmias (to 0.4+/-0.3 and 0.4+/-0.3 respectively) but not PVCs (to 390+/-234). Riluzole and lidocaine reduced the average number of sustained arrhythmias in phase 1b (from 1.8+/-0.4 to 0.17+/-0.13 (p<0.02) and to 0.55+/-0.26 (p = ns) respectively). Neither lidocaine or riluzole changed the ECG intervals: there was no statistical significance between groups at time zero (just before ligation) for any ECG measure. During the course of the 3 hour period of the ischaemia R-R, and P-R intervals shortened slightly in control and riluzole groups (not significantly different from each other) but not in the lidocaine group (significantly different from control). QRS and QTc did not change appreciably in any group Riluzole reduced the degree of histopathological tissue damage across the infarct zone considerably more than did lidocaine. CONCLUSIONS At the doses used, riluzole was at least as effective as lidocaine at reducing the number of episodes of ischaemic VT or VF in pigs, and much more effective at reducing the number of PVCs. We propose that this is related to the ability of riluzole to block cardiac persistent sodium current.
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Healey JS, Nair GM, Connolly SJ, Morillo CA. A rare cause of implantable cardioverter-defibrillator failure: Short-circuiting via an unused pace/sense lead. Heart Rhythm 2010; 7:1630-1. [DOI: 10.1016/j.hrthm.2010.07.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 07/17/2010] [Indexed: 10/19/2022]
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Tereshchenko LG, Faddis MN, Fetics BJ, Zelik KE, Efimov IR, Berger RD. Transient local injury current in right ventricular electrogram after implantable cardioverter-defibrillator shock predicts heart failure progression. J Am Coll Cardiol 2009; 54:822-8. [PMID: 19695461 DOI: 10.1016/j.jacc.2009.06.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 06/01/2009] [Accepted: 06/11/2009] [Indexed: 11/16/2022]
Abstract
OBJECTIVES This study aimed to identify an early marker of functional impairment after an implantable cardioverter-defibrillator (ICD) shock as a predictor of heart failure progression. BACKGROUND The ICD population has substantial risk of death due to progressive pump failure. METHODS Near-field (NF) bipolar right ventricular (RV) electrograms (EGMs) during induced ventricular fibrillation (VF) and 10 s after rescue ICD shock were analyzed in 310 patients (mean age 59 +/- 14.5 years, 219 men [71%]) with structural heart disease, New York Heart Association functional class I to III, and implanted with a single- or dual-chamber Medtronic (Minneapolis, Minnesota) ICD for primary (245 patients, 79%) or secondary prevention of sudden cardiac arrest. A local injury current (LIC) on NF RV EGM was defined as a deviation of EGM potential > or =1 mV or > or =15% of the preceding R-wave peak-to-peak amplitude. RESULTS During mean follow-up of 29.3 +/- 15.0 months, the combined end point of death or hospitalization due to congestive heart failure (CHF) exacerbation was documented in 40 patients (12.9%, or 5.3% per person-year of follow-up). LIC was observed in 106 patients. In multivariate risk analysis, after adjustment for baseline prognostic factors (ejection fraction, history of atrial fibrillation, diabetes mellitus) and appropriate ICD shocks during follow-up, patients with observed LIC after induced VF rescue ICD shock at ICD implantation were more likely to die or to be hospitalized (hazard ratio: 2.69; 95% confidence interval: 1.41 to 5.14; p = 0.003). CONCLUSIONS Transient LIC on bipolar NF RV EGM after induced VF rescue ICD shock is associated with increased risk of CHF progression, future hospitalizations due to CHF exacerbation, and subsequent heart failure death.
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Affiliation(s)
- Larisa G Tereshchenko
- Division of Cardiology, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland 21287, USA.
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Lawo T, Deneke T, Schrader J, Danilovic D, Wenzel B, Buddensiek M, Muegge A. A comparison of chronaxies for ventricular fibrillation induction, defibrillation, and cardiac stimulation: unexpected findings and their implications. J Cardiovasc Electrophysiol 2008; 20:307-14. [PMID: 19175850 DOI: 10.1111/j.1540-8167.2008.01319.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION A low-energy (<or= 4 J) cardioversion shock (LEC) either terminates reentrant ventricular tachycardia (VT) or accelerates it to ventricular fibrillation (VF). Optimization of the duration and amplitude of LEC shocks could improve the success rate of VT termination without VF induction. METHODS AND RESULTS In order to learn how LEC shocks may be optimized, we used an animal model to compare the strength-duration curve for VF induction and the strength-duration curve for cardiac stimulation via the shock coil. Conventional implantable cardioverter-defibrillator (ICD) leads were implanted in 12 narcotized pigs from 20 kg to 25 kg in weight. Stimulation, VF induction, and defibrillation pulses were delivered by custom-designed stimulators at preset pulse durations and amplitudes. The corresponding hyperbolic strength-duration curves were constructed using the least-squares fit method and averaged for all the animals. The mean chronaxie for stimulation via the shock coil of 0.23 ms was significantly shorter than both defibrillation (4.8 ms) and VF induction (3.1 ms) chronaxie values. At a shock duration of 0.3 ms or less, the mean VF-induction threshold amplitude exceeded 300 V. CONCLUSION It may be reasonable to study whether LEC pulses from 0.25 ms to 0.30 ms in duration and up to 250 V in amplitude would increase therapeutic yield in VT termination without VF induction in humans. Contrary to the current belief, the discrepancy between defibrillation and stimulation chronaxie is not caused by different electrode size. We postulate that the time constant of the fast sodium channel reactivation may be the underlying reason.
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Affiliation(s)
- Thomas Lawo
- Medical Clinic II (Cardiology), BG University Hospital Bergmannsheil, Bochum, Germany.
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Kim SC, Vasanji A, Efimov IR, Cheng Y. Spatial distribution and extent of electroporation by strong internal shock in intact structurally normal and chronically infarcted rabbit hearts. J Cardiovasc Electrophysiol 2008; 19:1080-9. [PMID: 18479336 PMCID: PMC2773614 DOI: 10.1111/j.1540-8167.2008.01201.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Although life-saving, a strong internal defibrillation shock may temporarily or permanently damage the heart via disruption of cell membranes (electroporation). Spatial extent of electroporation in intact, normal, or infarcted hearts has not been investigated. In this study, shock-induced electroporation in intact rabbit hearts with and without chronic (>4 weeks) left ventricular myocardial infarction (MI) was characterized. METHODS AND RESULTS A coil shock electrode was inserted in the right ventricle of Langendorff-perfused hearts. One truncated exponential monophasic shock (+300 V, 8 ms) was delivered by a 150 microF capacitor clinical defibrillator while the heart was perfused with membrane-impermeant dye propidium iodide (PI). The heart was sectioned transversely, and uptake of PI into ventricular myocardium through electropores was quantified. Histological evaluation was performed via Masson's trichrome staining. PI accumulation was minimal in the control (n = 3) and MI (n = 3) hearts without shock. Following shock delivery, (1) in control (n = 5) and MI (n = 5) hearts, electroporation mostly occurred near the shock electrode and was longitudinally distributed along the active region of the shock electrode; (2) in MI group, electroporation was significantly increased (P < 0.05) in the surviving anterior epicardial layers of the infarcted region; and (3) between the control and MI groups, the overall extent of electroporation was similar. CONCLUSION Shock-induced electroporation was spatially dependent on the location and dimension of the active region of the shock electrode. The overall extent of electroporation in the MI heart was comparable with the control heart, but the surviving anterior epicardial layers in the infarcted region were more susceptible to electroporation.
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Affiliation(s)
- Seok C Kim
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, Ohio 44195, USA
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SHEHATA MICHAEL, BELK PAUL, KREMERS MARK, SABA SAMIR, CAO JIAN, SWERDLOW CHARLESD. Automatic Determination of Timing Intervals for Upper Limit of Vulnerability Using ICD Electrograms. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2008; 31:691-700. [DOI: 10.1111/j.1540-8159.2008.01072.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Lemke B, Lawo T, Zarse M, Lubinski A, Kreutzer U, Mueller J, Schuchert A, Mitzenheim S, Danilovic D, Deneke T. Patient-tailored implantable cardioverter defibrillator testing using the upper limit of vulnerability: the TULIP protocol. Europace 2008; 10:907-13. [PMID: 18515789 DOI: 10.1093/europace/eun136] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS We evaluated the feasibility of the TULIP (Threshold test using Upper Limit during ImPlantation) protocol, which was designed to provide a confirmed, low defibrillation energy value during implantable cardioverter defibrillator (ICD) implantation with only two induced ventricular fibrillation (VF) episodes. METHODS AND RESULTS Ninety-eight patients (62 +/- 12 years, 86 male) from 13 clinical centres underwent an active can ICD implantation. A single coupling interval derived from electrocardiogram lead II during ventricular pacing was used for VF induction shocks at 13, 11, 9, and 6 J in a step-down manner until the upper limit of VF induction (ULVI) was determined. If ULVI >or=9 J, a defibrillation energy of ULVI + 4 J was tested. For ULVI <9 J, the defibrillation test energy was 9 J. In 79/98 patients (80.6%), two induced VF episodes were sufficient to obtain confirmed defibrillation energy of 11.1 +/- 3.3 J. The mean strength of the successful VF induction shock was 6.8 +/- 4.3 J, the coupling interval was 303 +/- 35 ms, and the number of delivered induction shocks until the first VF induction was 3.9 +/- 1.6. CONCLUSION TULIP is a safe and simple device testing procedure allowing the determination of confirmed, low defibrillation energy in most patients with two VF episodes induced at a single coupling interval.
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Affiliation(s)
- Bernd Lemke
- Department of Cardiology and Angiology, Medical Clinic II, BG University Hospital, Bergmannsheil, Bochum, Germany.
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Jacob S, Abraham AE, Mckelvey G. Anaesthetic Drugs and Defibrillation Threshold Testing. Drugs 2008; 68:1921-2; author reply 1922-3. [DOI: 10.2165/00003495-200868130-00012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Swerdlow CD. Small-diameter defibrillation electrodes: Can they take a licking and keep hearts ticking? Heart Rhythm 2007; 4:900-3. [PMID: 17599675 DOI: 10.1016/j.hrthm.2007.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Indexed: 10/23/2022]
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Epstein AE. Baseball, crackers, green dust, nose candy, and snow cones: cocaine, defibrillation, and ICDs. J Cardiovasc Electrophysiol 2007; 18:726-7. [PMID: 17532777 DOI: 10.1111/j.1540-8167.2007.00856.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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