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Panchangam S, Monahan KM, Helm RH. Anti-tachycardia Pacing: Mechanism, History and Contemporary Implementation. CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2022. [DOI: 10.1007/s11936-022-00959-0] [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: 10/19/2022]
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2
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Viskin S, Rosso R. Should we do 'whatever it takes' or 'whatever is best' to prevent cardiac arrest in high-risk patients? Eur Heart J 2019; 40:2962-2963. [PMID: 31219566 DOI: 10.1093/eurheartj/ehz415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Affiliation(s)
- Sami Viskin
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Raphael Rosso
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Le KV, Okamura H, Nakajima K, Noda T, Kusano K. Undersensing of ventricular fibrillation by a biventricular implantable cardioverter-defibrillator: What is the cause and the troubleshooting? J Arrhythm 2019; 35:276-278. [PMID: 31007793 PMCID: PMC6457377 DOI: 10.1002/joa3.12170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 12/17/2018] [Accepted: 01/06/2019] [Indexed: 11/17/2022] Open
Affiliation(s)
- Kien Vo Le
- Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Hideo Okamura
- Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Kenzaburo Nakajima
- Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Takashi Noda
- Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Kengo Kusano
- Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
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Evaluation of defibrillation safety and shock reduction in implantable cardioverter-defibrillator patients with increased time to detection: A randomized SANKS study. J Arrhythm 2015; 31:94-100. [PMID: 26336539 DOI: 10.1016/j.joa.2014.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/28/2014] [Accepted: 08/05/2014] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The need for ways to minimize the number of implantable cardioverter-defibrillator (ICD) shocks is increasing owing to the risk of its adverse effects on life expectancy. Studies have shown that a longer detection time for ventricular tachyarrhythmia reduces the safety of therapies, in terms of syncope and mortality, but not substantially in terms of the success rate. We aimed to evaluate the effects of increased number of intervals to detect (NID) VF on the safety of ICD shock therapy and on the reduction of inappropriate shocks. METHODS The present study was a prospective, multicenter, randomized, crossover study. Randomized VF induction testing with NID 18/24 or 30/40 was performed to compare the success rate of defibrillation with a 25-J shock and the time to detection. Inappropriate shock episodes were simulated retrospectively to evaluate a possibility of episodes avoidable at NID 24/32 and 30/40. RESULTS Thirty-one consecutive patients implanted with an ICD or cardiac resynchronization therapy-defibrillator (CRT-D) were enrolled in this study. The success rate of defibrillation was 100% in both NID groups at the first shock. The time from VF induction to detection showed a significant increase in the NID 30/40 group (6.16±1.29 s vs. 9.00±1.31 s, p<0.001). Among the 120 patients implanted with an ICD or CRT-D, 10 experienced 32 inappropriate shock episodes. The inappropriate shock reduction rate was 53.1% and 62.5% with NID 24/32 and 30/40, respectively. CONCLUSIONS The findings of this SANKS study suggest that VF NID 30/40 does not compromise the safety of ICD shock therapy, while decreasing the number of inappropriate shocks.
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5
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Biphasic versus monophasic defibrillation in out-of-hospital cardiac arrest: a systematic review and meta-analysis. Am J Emerg Med 2013; 31:1472-8. [PMID: 24035505 DOI: 10.1016/j.ajem.2013.07.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 06/09/2013] [Accepted: 07/18/2013] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE Biphasic defibrillation is more effective than monophasic one in controlled in-hospital conditions. The present review evaluated the performance of both waveforms in the defibrillation of patients of out-of-hospital cardiac arrest (OHCA) with initial ventricular fibrillation (Vf) rhythm under the context of current recommendations for cardiopulmonary resuscitation. METHODS From inception to June 2012, Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched systemically for randomized controlled trials (RCTs) and observational cohort studies that compared the effects of biphasic and monophasic shocks on Vf termination, return of spontaneous circulation (ROSC), and survival to hospital discharge in OHCA patients with initial Vf rhythm. No restrictions were applied regarding language, population, or publication year. RESULTS Four RCTs including 572 patients were identified from 131 potentially relevant references for meta-analysis. The synthesis of these RCTs yielded fixed-effect pooled risk ratios (RRs) for biphasic and monophasic waveforms on Vf termination survival to hospital discharge (RR, 1.14; 95% CI, [0.84-1.54]). CONCLUSION Biphasic waveforms did not seem superior to monophasic ones with respect to Vf termination, ROSC, or survival to hospital discharge in OHCA patients with initial Vf rhythm under the context of current guidelines. However, most trials were conducted in accordance with previous guidelines for cardiopulmonary resuscitation. Therefore, further trials are needed to clarify this issue.
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HIRSH DAVIDS, CHINITZ LARRYA, BERNSTEIN NEILE, HOLMES DOUGLASS, RAO SATYA, AIZER ANTHONY. Clinical Comparison of ICD Detection Algorithms that Include Rapid-VT Zones. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2012; 35:1222-31. [DOI: 10.1111/j.1540-8159.2011.03315.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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7
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SMITS KAREL, VIRAG NATHALIE. Impact of Defibrillation Test Protocol and Test Repetition on the Probability of Meeting Implant Criteria. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2011; 34:1515-26. [DOI: 10.1111/j.1540-8159.2011.03166.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Lim HS, Flannigan S, Marshall H. Induction by direct current pulse versus 50-Hz pacing on ventricular fibrillation and defibrillation. J Interv Card Electrophysiol 2010; 28:209-14. [PMID: 20461546 DOI: 10.1007/s10840-010-9486-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2009] [Accepted: 03/23/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND Ventricular fibrillation (VF) induced by different modes of induction may have different characteristics and defibrillation thresholds. This study compares the cycle lengths and defibrillation of VF induced by direct current (DC) pulses vs 50 Hz. METHOD We compared induction by DC pulses and 50-Hz pacing in this single-centre observational study of 259 consecutive patients with implantable cardioverter defibrillators in 2007-2008. Patients with inadequate defibrillation safety margin (DSM), defined as unsuccessful defibrillation at 25 J, were identified. RESULTS Of the 259 patients, 132 underwent induction with DC pulses and 127 with 50-Hz pacing. DC pulses induced VF of shorter cycle lengths (207 ± 16 vs 231 ± 24 ms, p < 0.001) compared to 50-Hz pacing. There were 17 patients (6.6%) with inadequate DSM-13/132 (9.8%) with DC pulse vs 4/127 (3.1%) with 50-Hz pacing (p < 0.001). The induced VF cycle lengths were shorter in patients with inadequate DSM (186 ± 25 vs 221 ± 21 ms, p < 0.001). On multivariate analysis, only the induced VF cycle length (p = 0.002) was independently associated with inadequate DSM. CONCLUSION VF of shorter cycle lengths is independently associated with inadequate DSM. DC pulses are associated with greater proportion of patients with inadequate DSM as it induces VF of shorter cycle lengths compared to 50-Hz pacing.
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Affiliation(s)
- Hoong Sern Lim
- University Hospital Birmingham NHS Trust, Edgbaston, Birmingham B15 2TH, UK.
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9
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Estimating the Parameter Distributions of Defibrillation Shock Efficacy Curves in a Large Population. Ann Biomed Eng 2010; 38:1314-25. [DOI: 10.1007/s10439-009-9890-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Accepted: 12/24/2009] [Indexed: 10/20/2022]
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10
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Bright JM, Wright BD. Successful biphasic transthoracic defibrillation of a dog with prolonged, refractory ventricular fibrillation. J Vet Emerg Crit Care (San Antonio) 2009; 19:275-9. [DOI: 10.1111/j.1476-4431.2009.00408.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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KOLB CHRISTOF, TZEIS STYLIANOS, ZRENNER BERNHARD. Defibrillation Threshold Testing: Tradition or Necessity? PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2009; 32:570-2; discussion 572. [DOI: 10.1111/j.1540-8159.2009.02328.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Nagai T, Kurita T, Satomi K, Noda T, Okamura H, Shimizu W, Suyama K, Aihara N, Kobayashi J, Kamakura S. QRS prolongation is associated with high defibrillation thresholds during cardioverter-defibrillator implantations in patients with hypertrophic cardiomyopathy. Circ J 2009; 73:1028-32. [PMID: 19359812 DOI: 10.1253/circj.cj-08-0744] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Although high defibrillation threshold (DFT) is a major and unavoidable clinical problem after implantation of an implantable cardioverter defibrillator (ICD), little is known about the cause and management of a high DFT in patients with hypertrophic cardiomyopathy (HCM). The purpose of this study was to assess the predictors of a high DFT in patients with HCM. METHODS AND RESULTS Twenty-three patients with non-dilated HCM who underwent ICD implantation were included. The DFT at the time of the device implantation was measured in all patients. The patients were divided into 2 groups, a high DFT group (DFT >or=15J, n=13) and a low DFT group (DFT <15J, n=10); and their baseline characteristics were compared. The QRS duration was longer in the high than in the low DFT group (128 +/-31 vs 103 +/-12 ms, respectively; P=0.02). QRS duration, left ventricular (LV) end-systolic diameter, and LV ejection fraction were significant predictors of DFT in univariate analysis. However, in multivariate analysis, the only factor significantly associated with DFT was QRS duration (P=0.002). CONCLUSIONS QRS duration is the most consistent predictor of a high DFT in HCM patients undergoing ICD implantation.
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Affiliation(s)
- Takayuki Nagai
- Division of Cardiology, Department of Internal Medicine, National Cardiovascular Center, Suita, Japan
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Mischke K, Schimpf T, Knackstedt C, Eickholt C, Hanrath P, Kelm M, Schauerte P. Efficacy of transesophageal defibrillation in ventricular fibrillation of long duration. Am J Emerg Med 2008; 26:287-90. [DOI: 10.1016/j.ajem.2007.05.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Revised: 04/06/2007] [Accepted: 05/05/2007] [Indexed: 11/26/2022] Open
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Swerdlow CD, Russo AM, Degroot PJ. The dilemma of ICD implant testing. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2007; 30:675-700. [PMID: 17461879 DOI: 10.1111/j.1540-8159.2007.00730.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ventricular fibrillation (VF) has been induced at implantable cardioverter defibrillator (ICD) implant to ensure reliable sensing, detection, and defibrillation. Despite its risks, the value was self-evident for early ICDs: failure of defibrillation was common, recipients had a high risk of ventricular tachycardia (VT) or VF, and the only therapy for rapid VT or VF was a shock. Today, failure of defibrillation is rare, the risk of VT/VF is lower in some recipients, antitachycardia pacing is applied for fast VT, and vulnerability testing permits assessment of defibrillation efficacy without inducing VF in most patients. This review reappraises ICD implant testing. At implant, defibrillation success is influenced by both predictable and unpredictable factors, including those related to the patient, ICD system, drugs, and complications. For left pectoral implants of high-output ICDs, the probability of passing a 10 J safety margin is approximately 95%, the probability that a maximum output shock will defibrillate is approximately 99%, and the incidence of system revision based on testing is < or = 5%. Bayes' Theorem predicts that implant testing identifies < or = 50% of patients at high risk for unsuccessful defibrillation. Most patients who fail implant criteria have false negative tests and may undergo unnecessary revision of their ICD systems. The first-shock success rate for spontaneous VT/VF ranges from 83% to 93%, lower than that for induced VF. Thus, shocks for spontaneous VT/VF fail for reasons that are not evaluated at implant. Whether system revision based on implant testing improves this success rate is unknown. The risks of implant testing include those related to VF and those related to shocks alone. The former may be due to circulatory arrest alone or the combination of circulatory arrest and shocks. Vulnerability testing reduces risks related to VF, but not those related to shocks. Mortality from implant testing probably is 0.1-0.2%. Overall, VF should be induced to assess sensing in approximately 5% of ICD recipients. Defibrillation or vulnerability testing is indicated in 20-40% of recipients who can be identified as having a higher-than-usual probability of an inadequate defibrillation safety margin based on patient-specific factors. However, implant testing is too risky in approximately 5% of recipients and may not be worth the risks in 10-30%. In 25-50% of ICD recipients, testing cannot be identified as either critical or contraindicated.
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Affiliation(s)
- Charles D Swerdlow
- Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, and the David Geffen School of Medicine, UCLA, Los Angeles, California, USA.
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15
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Schoels W, Steinhaus D, Johnson WB, O'hara G, Schwab JO, Jenniskens I, Degroot PJ, Tang F, Helmling E. Optimizing implantable cardioverter-defibrillator treatment of rapid ventricular tachycardia: Antitachycardia pacing therapy during charging. Heart Rhythm 2007; 4:879-85. [PMID: 17599671 DOI: 10.1016/j.hrthm.2007.03.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 03/05/2007] [Indexed: 11/20/2022]
Abstract
BACKGROUND Previous studies in implantable cardioverter-defibrillator (ICD) patients demonstrated the efficacy and safety of antitachycardia pacing (ATP) for rapid ventricular tachycardias (VT). To prevent shock delay in case of ATP failure, a new feature (ATP during charging) was developed to deliver ATP for rapid VT while charging for shock. OBJECTIVE The purpose of this study was to determine the efficacy and safety of this new feature. METHODS In a prospective, nonrandomized trial, patients with standard ICD indication received an EnTrust ICD. VT and ventricular fibrillation (VF) episodes were reviewed for appropriate detection, ATP success, rhythm acceleration, and related symptoms. RESULTS In 421 implanted patients, 116 VF episodes occurred in 37 patients. Eighty-four (72%) episodes received ATP during or before charging. ATP prevented a shock in 58 (69%) of 84 episodes in 15 patients. ATP stopped significantly more monomorphic (77%) than polymorphic VTs (44%, P = .05). Five (6%) episodes accelerated after ATP but were terminated by the backup shock(s). No symptoms were related to ATP during charging. In four patients, 38 charges were saved by delivering ATP before charging. Of 98 induced VF episodes, 28% were successfully terminated by ATP versus 69% for spontaneous episodes (P <.01). CONCLUSION Most VTs detected in the VF zone can be painlessly terminated by ATP delivered during charging, with a low risk of acceleration or symptoms. ATP before charging allows delivery of two ATP attempts before shock in the same time that would otherwise be required to deliver only one ATP plus a shock. It also offers potential battery energy savings.
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Affiliation(s)
- Wolfgang Schoels
- Evangelisches und Johanniter Klinikum Niederrhein GmbH, Herzzentrum Duisburg, Klinik für Kardiologie und Angiologie, Duisburg, Germany
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Kudenchuk PJ, Cobb LA, Copass MK, Olsufka M, Maynard C, Nichol G. Transthoracic Incremental Monophasic Versus Biphasic Defibrillation by Emergency Responders (TIMBER). Circulation 2006; 114:2010-8. [PMID: 17060379 DOI: 10.1161/circulationaha.106.636506] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Although biphasic, as compared with monophasic, waveform defibrillation for cardiac arrest is increasing in use and popularity, whether it is truly a more lifesaving waveform is unproven.
Methods and Results—
Consecutive adults with nontraumatic out-of-hospital ventricular fibrillation cardiac arrest were randomly allocated to defibrillation according to the waveform from automated external defibrillators administered by prehospital medical providers. The primary event of interest was admission alive to the hospital. Secondary events included return of rhythm and circulation, survival, and neurological outcome. Providers were blinded to automated defibrillator waveform. Of 168 randomized patients, 80 (48%) and 68 (40%) consistently received only monophasic or biphasic waveform shocks, respectively, throughout resuscitation. The prevalence of ventricular fibrillation, asystole, or organized rhythms at 5, 10, or 20 seconds after each shock did not differ significantly between treatment groups. The proportion of patients admitted alive to the hospital was relatively high: 73% in monophasic and 76% in biphasic treatment groups (
P
=0.58). Several favorable trends were consistently associated with receipt of biphasic waveform shock, none of which reached statistical significance. Notably, 27 of 80 monophasic shock recipients (34%), compared with 28 of 68 biphasic shock recipients (41%), survived (
P
=0.35). Neurological outcome was similar in both treatment groups (
P
=0.4). Earlier administration of shock did not significantly alter the performance of one waveform relative to the other, nor did shock waveform predict any clinical outcome after multivariate adjustment.
Conclusions—
No statistically significant differences in outcome could be ascribed to use of one waveform over another when out-of-hospital ventricular fibrillation was treated.
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Mischke K, Schimpf T, Knackstedt C, Zarse M, Eickholt C, Plisiene J, Frechen D, Gramley F, Schauerte P. Potential benefit of transesophageal defibrillation: an experimental evaluation. Am J Emerg Med 2006; 24:418-22. [PMID: 16787798 DOI: 10.1016/j.ajem.2005.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Revised: 12/14/2005] [Accepted: 12/17/2005] [Indexed: 10/24/2022] Open
Abstract
INTRODUCTION Because of the proximity of the esophagus to the heart, transesophageal defibrillation might increase defibrillation success. We assessed the defibrillation threshold (DFT) of transesophageal defibrillation compared with standard transthoracic defibrillation. METHODS Defibrillation success and DFTs were determined in 22 female pigs with high (68+/-4 kg, n=12) or low body weight (39+/-1 kg, n=10). After induction of ventricular fibrillation, biphasic shocks were delivered between two cutaneous patch electrodes (sternal and apical position) or between an esophageal and two cutaneous patch electrodes in a sternal and apical position. The esophageal electrode was integrated into a latex sheath covering a standard transesophageal echocardiography probe. RESULTS In 5 of 12 pigs with high body weight, external defibrillation failed despite 3 consecutive 200-J shocks, whereas subsequent transesophageal defibrillation was successful with the first shock. In the remaining 7 pigs, a more than 50% reduction in DFT was obtained with transesophageal defibrillation compared with standard biphasic external defibrillation (67+/-27 vs 164+/-23 J, P<.001). Pigs with lower body weight were successfully defibrillated by both transthoracic and transesophageal shocks. The DFT in pigs with low body weight was significantly lower using transesophageal defibrillation compared with transthoracic shocks (65+/-15 vs 99+/-38 J, P<.05). CONCLUSIONS In this animal model, nonresponders to standard external defibrillation could successfully be defibrillated via an esophageal-cutaneous electrode configuration. Overall, an almost 50% DFT reduction was achieved by transesophageal defibrillation. Transesophageal defibrillation may provide an additional tool for terminating VF, which is refractory to external defibrillation, eg, in patients with very high body weight.
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Affiliation(s)
- Karl Mischke
- Department of Cardiology, RWTH Aachen University, 52074 Aachen, Germany.
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Gelzer AR, Moïse NS, Koller ML. Defibrillation of German shepherds with inherited ventricular arrhythmias and sudden death. J Vet Cardiol 2005; 7:97-107. [DOI: 10.1016/j.jvc.2005.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Revised: 09/23/2005] [Accepted: 09/25/2005] [Indexed: 10/25/2022]
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Carlsson J, Schulte B, Erdogan A, Sperzel J, Güttler N, Schwarz T, Pitschner HF, Neuzner J. Prospective randomized comparison of two defibrillation safety margins in unipolar, active pectoral defibrillator therapy. Pacing Clin Electrophysiol 2003; 26:613-8. [PMID: 12710322 DOI: 10.1046/j.1460-9592.2003.00102.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Various techniques are used to establish defibrillation efficacy and to evaluate defibrillation safety margins in patients with an ICD. In daily practice a safety margin of 10 J is generally accepted. However, this is based on old clinical data and there are no data on safety margins using current ICD technology with unipolar, active pectoral defibrillators. Therefore, a randomized study was performed to test if the likelihood of successful defibrillation at defibrillation energy requirement (DER) + 5 J and + 10 J is equivalent. Ninety-six patients (86 men; age 61.0 +/- 10.3 years; ejection fraction 0.341 +/- 0.132; coronary artery disease [n = 65], dilated cardiomyopathy [n = 18], other [n = 13]) underwent implantation of an active pectoral ICD system with unidirectional current pathway and a truncated, fixed tilt biphasic shock waveform. The defibrillation energy requirement (DER) was determined with the use of a step-down protocol (delivered energy 15, 10, 8, 6, 4, 3, 2 J). The patients were then randomized to three inductions of ventricular fibrillation at implantation and three at predischarge testing with shock strengths programmed to DER + 5 J at implantation and + 10 J at predischarge testing or vice versa. The mean DER in the total study population was 7.88 +/- 2.96 J. The number of defibrillation attempts was 288 for + 5 J and 288 for + 10 J. The rate of successful defibrillation was 94.1% (DER + 5 J) and 98.9% (DER + 10 J; P < 0.01 for equivalence). Charge times for DER + 5 J were significantly shorter than for DER + 10 J (3.65 +/- 1.14 vs 5.45 +/- 1.47 s; P < 0.001). A defibrillation safety margin of DER + 5 J is associated with a defibrillation probability equal to the standard DER + 10 J. In patients in whom short charge times are critical for avoidance of syncope, a safety margin of DER + 5 J seems clinically safe for programming of the first shock energy.
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Affiliation(s)
- Joerg Carlsson
- Department of Cardiology, Kerckhoff-Clinic, Bad Nauheim, Germany.
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Eason J, Gades NM, Malkin RA. A novel ultrasound technique to estimate right ventricular geometry during fibrillation. Physiol Meas 2002; 23:269-78. [PMID: 12051299 DOI: 10.1088/0967-3334/23/2/303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Finite element modelling of the heart for the purpose of studying the electric fields of defibrillation shocks requires knowledge of the geometry of the heart during fibrillation. However, the standard method of measuring this geometry, MRI. cannot be used during fibrillation because the heart geometry changes rapidly and perhaps unpredictably. We present a new ultrasound approach to measuring the right ventricular geometry during fibrillation and preliminary data using this technique. In six anaesthetized pigs, we find that a short axis cross-sectional area of the right ventricle increases by 38% during a 30 s episode of ventricular fibrillation. A long axis cross-sectional area increases by 19% during this same time. By fitting parameters of a simple geometric model to the experimental data, we estimate that the volume of blood in the right ventricular cavity increases by approximately 30% during the episode of ventricular fibrillation. We present the first study of the RV area during-fibrillation with the estimated volume. Our data suggest changes in defibrillation threshold may be linked to current shunting through the increased blood volume.
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Affiliation(s)
- James Eason
- The Joint Program in Biomedical Engineering at The University of Memphis, TN 38152, USA
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Wathen MS, Sweeney MO, DeGroot PJ, Stark AJ, Koehler JL, Chisner MB, Machado C, Adkisson WO. Shock reduction using antitachycardia pacing for spontaneous rapid ventricular tachycardia in patients with coronary artery disease. Circulation 2001; 104:796-801. [PMID: 11502705 DOI: 10.1161/hc3101.093906] [Citation(s) in RCA: 215] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Implantable cardioverter-defibrillators (ICDs) can terminate some ventricular tachycardias (VTs) painlessly with antitachycardia pacing (ATP). ATP has not routinely been applied for VT >188 bpm because of concerns about efficacy, risk of acceleration, and delay of definitive shock therapy. This prospective, multicenter study evaluated the efficacy of empirical ATP to terminate fast VT (FVT; >188 bpm). METHODS AND RESULTS Two hundred twenty coronary artery disease patients received ICDs for standard indications. Empirical, standardized therapy was programmed so that all FVT episodes (average cycle length [CL] 240 to 320 ms, 250 to 188 bpm) were treated with 2 ATP sequences (8-pulse burst pacing train at 88% of the FVT CL) before shock delivery. A total of 1100 episodes of spontaneous ventricular tachyarrhythmias occurred during a mean of 6.9+/-3.6 months of follow-up. Fifty-seven percent were classified as slow VT (CL>/=320 ms), 40% as FVT (240 ms</=CL<320 ms), and 3% as ventricular fibrillation (CL<240 ms). A total of 446 FVT episodes, mean CL=301+/-24 ms, occurred in 52 patients (median 2 episodes per patient). ATP terminated 396 FVT episodes (89%), with an adjusted efficacy of 77% (95% CI 68% to 83%). VT acceleration caused by ATP occurred in 10 FVT episodes (4%). FVT arrhythmic syncope occurred on 9 occasions (2%) in 4 patients. CONCLUSIONS FVT (CL<320 ms) is common in ICD patients. ATP can terminate 3 of 4 of these episodes with a low incidence of acceleration and syncope. ATP for FVT may safely reduce the morbidity of painful shocks.
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Affiliation(s)
- M S Wathen
- Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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22
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Bain AC, Swerdlow CD, Love CJ, Ellenbogen KA, Deering TF, Brewer JE, Augostini RS, Tchou PJ. Multicenter study of principles-based waveforms for external defibrillation. Ann Emerg Med 2001; 37:5-12. [PMID: 11145764 DOI: 10.1067/mem.2001.111690] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
STUDY OBJECTIVE The efficacy of a shock waveform for external defibrillation depends on the waveform characteristics. Recently, design principles based on cardiac electrophysiology have been developed to determine optimal waveform characteristics. The objective of this clinical trial was to evaluate the efficacy of principles-based monophasic and biphasic waveforms for external defibrillation. METHODS A prospective, randomized, blinded, multicenter study of 118 patients undergoing electrophysiologic testing or receiving an implantable defibrillator was conducted. Ventricular fibrillation was induced, and defibrillation was attempted in each patient with a biphasic and a monophasic waveform. Patients were randomly placed into 2 groups: group 1 received shocks of escalating energy, and group 2 received only high-energy shocks. RESULTS The biphasic waveform achieved a first-shock success rate of 100% in group 1 (95% confidence interval [CI] 95.1% to 100%) and group 2 (95% CI 94.6% to 100%), with average delivered energies of 201+/-17 J and 295+/-28 J, respectively. The monophasic waveform demonstrated a 96.7% (95% CI 89.1% to 100%) first-shock success rate and average delivered energy of 215+/-12 J for group 1 and a 98.2% (95% CI 91.7% to 100%) first-shock success rate and average delivered energy of 352+/-13 J for group 2. CONCLUSION Using principles of electrophysiology, it is possible to design both biphasic and monophasic waveforms for external defibrillation that achieve a high first-shock efficacy.
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Affiliation(s)
- A C Bain
- Survivalink Corporation, Minneapolis, MN, USA.
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23
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Abstract
Implantable cardioverter-defibrillators (ICDs) have become the dominant therapeutic modality for patients with life-threatening ventricular arrhythmias. ICDs are implanted using techniques similar to standard pacemaker implantation. They not only provide high-energy shocks for ventricular fibrillation and rapid ventricular tachycardia, but also provide antitachycardia pacing for monomorphic ventricular tachycardia and antibradycardia pacing. Devices incorporating an atrial lead allow dual-chamber pacing and better discrimination between ventricular and supraventricular tachyarrhythmias. Intensivists are increasingly likely to encounter patients with ICDs. Electrosurgery can be safely performed in ICD patients as long as the device is deactivated before the procedure and reactivated and reassessed immediately afterward. Prompt and skilled intervention can prove to be life-saving in patients presenting with ICD-related emergencies, including lack of response to ventricular tachyarrhythmias, pacing failure, and multiple shocks. Recognition and treatment of tachyarrhythmia can be temporarily disabled by placing a magnet on top of an ICD. The presence of an ICD should not deter standard resuscitation techniques. Multiple ICD discharges in a short period of time constitute a serious situation. Causes include ventricular electrical storm, inefficient defibrillation, nonsustained ventricular tachycardia, and inappropriate shocks caused by supraventricular tachyarrhythmias or oversensing of signals. ICD system infection requires hardware removal and intravenous antibiotic therapy. Deactivation of an ICD with the consent of the patient or relatives is reasonable and ethical in terminally ill patients.
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Affiliation(s)
- S L Pinski
- Section of Cardiology, Rush-Presbyterian-St. Luke's Medical Center and Rush Medical College, Chicago, IL 60612, USA.
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24
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Leng CT, Paradis NA, Calkins H, Berger RD, Lardo AC, Rent KC, Halperin HR. Resuscitation after prolonged ventricular fibrillation with use of monophasic and biphasic waveform pulses for external defibrillation. Circulation 2000; 101:2968-74. [PMID: 10869271 DOI: 10.1161/01.cir.101.25.2968] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Survival after prolonged ventricular fibrillation (VF) appears severely limited by 2 major factors: (1) low defibrillation success rates and (2) persistent post-countershock myocardial dysfunction. Biphasic (BP) waveforms may prove capable of favorably modifying these limitations. However, they have not been rigorously tested against monophasic (MP) waveforms in clinical models of external defibrillation, particularly where rescue from prolonged VF is the general rule. METHODS AND RESULTS We randomized 26 dogs to external countershocks with either MP or BP waveforms. Hemodynamics were assessed after shocks applied during sinus rhythm, after brief VF (>10 seconds), and after resuscitation from prolonged VF (>10 minutes). Short-term differences in percent change in left ventricular +dP/dt(max) (MP -16+/-28%, BP +9.1+/-24%; P=0.03) and left ventricular -dP/dt(max) (MP -37+/-26%, BP -18+/-20%; P=0.05) were present after rescue from brief VF, with BP animals exhibiting less countershock-induced dysfunction. After prolonged VF, the BP group had lower mean defibrillation thresholds (107+/-57 versus 172+/-88 J for MP, P=0.04) and significantly shorter resuscitation times (397+/-73.7 versus 488+/-74.3 seconds for MP, P=0.03). CONCLUSIONS External defibrillation is more efficacious with BP countershocks than with MP countershocks. The lower defibrillation thresholds and shorter resuscitation times associated with BP waveform defibrillation may improve survival after prolonged VF arrest.
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Affiliation(s)
- C T Leng
- Division of Cardiology, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, MD, USA.
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25
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Trusty JM, Hayes DL, Stanton MS, Friedman PA. Factors affecting the frequency of subcutaneous lead usage in implantable defibrillators. Pacing Clin Electrophysiol 2000; 23:842-6. [PMID: 10833704 DOI: 10.1111/j.1540-8159.2000.tb00853.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Subcutaneous leads (SQ) add complexity to the defibrillation system and the implant procedure. New low output devices might increase the requirement for SQ arrays, although this might be offset by the effects of active can and biphasic technology. This study sought to assess the impact of these technologies on SQ lead usage, and to determine if clinical variables could predict the need for an SQ lead. Patients receiving nonthoracotomy systems (n = 554) at our institution underwent step-down-to-failure DFT testing with implant criteria of a 10-J safety margin. SQ leads were used only after several endovascular configurations failed. Use of biphasic waveforms significantly lowered the frequency of use of SQ leads from 48% to 3.7% (P < 0.000001). SQ leads were required in 4.4% of patients with cold can devices and 2.6% of patients with active can devices (P = NS). There was no increase in SQ lead usage with low energy (< 30-J delivered energy) devices. Clinical variables (including EF, heart disease, arrhythmia, and prior bypass) did not predict the need for an SQ lead. The implant DFT using SQ arrays (14.5 +/- 6.5 J) was not significantly lower than that for SQ patches (16.6 + 6.0 J). We conclude that biphasic waveforms significantly reduce the need for SQ leads. Despite this reduction, 3.7% of implants still use an SQ lead to achieve adequate safety margins. The introduction of lower output devices has not increased the need for SQ leads, and when an SQ lead is required, there is not a significant difference in the implant DFT of patches versus arrays. Clinical variables cannot predict which patients require SQ leads.
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Affiliation(s)
- J M Trusty
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA
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26
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Washizuka T, Chinushi M, Hatada K, Kasai H, Ohhira K, Furushima H, Aizawa Y. Both low and high energy cardioversion induced accelerated ventricular tachycardia in a patient treated with an implantable cardioverter defibrillator. JAPANESE HEART JOURNAL 1999; 40:665-9. [PMID: 10888386 DOI: 10.1536/jhj.40.665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A 72-year old male with an old myocardial infarction who had drug-refractory ventricular tachyarrhythmias received an implantable cardioverter-defibrillator (ICD). The patient did not take his prescribed beta-blocking agent for two days, following which he experienced six discrete shocks for spontaneous VT while riding his bicycle. Both 5J and 30J cardioversions were ineffective at terminating the VT and accelerated VT developed following the shocks. After admission, an electrophysiological study was performed while he was taking the beta-blocking agent, both low and high energy cardioversions reproducibly terminated the clinical VT without showing any accelerated rhythm. These findings suggest that the increase in sympathetic discharge may enhance the proarrhythmic potential of ICDs.
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Affiliation(s)
- T Washizuka
- First Department of Internal Medicine, Niigata University School of Medicine, Asahimachi, Japan
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