Safety and efficacy of implantable defibrillator therapy with programmed shock energy at twice the augmented step-down defibrillation threshold: results of the prospective, randomized, multicenter low-energy endotak trial

Neuzner, J.; Liebrich, Andreas; Jung, Jens; Himmrich, Ewald; Pitschner, Heinz F.; Winter, Joachim; Vester, E. G.; Michel, U.; Nisam, Seah; Heisel, Armin

doi:10.1016/s0002-9149(99)00037-5

Cited by 32 publications

(26 citation statements)

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“…6,7) However, neither the efficacy nor benefit of DFT testing has been proven. [8][9][10][11] Induction of ventricular fibrillation (VF) during DFT can cause hemodynamic compromise, clinical deterioration, and life-threatening cerebrovascular accidents.…”

Section: Mplantable Cardioverter-defibrillators (Icds) Have Beenmentioning

confidence: 99%

Assessment of Efficacy and Necessity of Routine Defibrillation Threshold Testing in Patients Undergoing Implantable Cardioverter-Defibrillator (ICD) Implantation

et al. 2015

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SummaryDefibrillation threshold (DFT) testing is performed routinely in patients undergoing implantable cardioverter-defibrillator (ICD) implantation to verify the ability of the ICD to terminate ventricular fibrillation (VF). However, neither the efficacy nor the safety of DFT testing has been proven; thus, the necessity of such testing is controversial. We conducted a retrospective study of the efficacy of DFT testing, particularly with respect to long-term outcomes of ICD implantation.The study included 150 patients (125 men, 25 women, aged 59.0 ± 17.6 years) who underwent ICD or cardiac resynchronization therapy defibrillator implantation, with (n = 73) or without (n = 77) intraoperative DFT testing, between June 1996 and September 2007. VF was induced by delivery of a T-wave shock, and a 20-25-J shock was then delivered. If the 20-25-J shock failed to terminate VF, 30 J was delivered. We assessed whether undersensed VF events occurred during DFT testing and/or during patient follow-up and checked for any association between undersensing and delayed shock delivery. During DFT testing, fine VF was sensed, and shocks were delivered in a timely manner. Nevertheless, 2 patients in the DFT testing group died from VF within 3 years after device implantation.DFT testing, in comparison to non-DFT testing, appeared to have no influence on the long-term outcomes of our patients, suggesting that DFT testing at the time of ICD implantation is limited. (Int Heart J 2015; 56: 618-621) Key words: Ventricular arrhythmia, Mortality I mplantable cardioverter-defibrillators (ICDs) have been shown to reduce mortality resulting from both ischemic 1,2) and non-ischemic cardiomyopathies 2) and to terminate potentially fatal ventricular arrhythmias.3,4) Current indications for an ICD include not only a near-fatal arrhythmic event 5) and ischemic cardiomyopathy but also severe nonischemic cardiomyopathy with a low left ventricular ejection fraction (LVEF).Defibrillation threshold (DFT) testing during ICD implantation has been considered necessary for appropriate shock delivery, 6) and a DFT safety margin of 10 J is the standard recommendation.6,7) However, neither the efficacy nor benefit of DFT testing has been proven. [8][9][10][11] Induction of ventricular fibrillation (VF) during DFT can cause hemodynamic compromise, clinical deterioration, and life-threatening cerebrovascular accidents.12-15) Thus, we conducted a retrospective study to assess the effect of DFT testing on long-term outcomes in patients with an ICD or cardiac resynchronization therapy defibrillator (CRT-D). MethodsStudy patients: The study included 150 patients (125 men, 25 women) who received an ICD (n = 85) or CRT-D (n = 65) at our hospital between June 1996 and September 2007. Hospital records were obtained, from which we extracted the patient clinical characteristics, follow-up times, ICD intracardiac recordings, and clinical outcomes. The ICDs and CRT-Ds were implanted in a standard transvenous manner. We divided the patients into 2 groups, those in whom DFT...

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Section: Mplantable Cardioverter-defibrillators (Icds) Have Beenmentioning

confidence: 99%

Assessment of Efficacy and Necessity of Routine Defibrillation Threshold Testing in Patients Undergoing Implantable Cardioverter-Defibrillator (ICD) Implantation

et al. 2015

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“…At the end of the ICD implantation after ventricular fibrillation was induced using a T-wave shock or 50-Hz burst pacing, DFT was measured using a step-down method from an initial delivered energy of 15J with decrements of 5J. 9,10 If the initial 15J shock failed, the energy was increased in 5J steps until defibrillation was successful. A 5-min interval was allowed between inductions and defibrillations of ventricular fibrillation.…”

Section: Icd Implantation and Dft Testingmentioning

confidence: 99%

QRS Prolongation is Associated With High Defibrillation Thresholds During Cardioverter-Defibrillator Implantations in Patients With Hypertrophic Cardiomyopathy

Nagai

Kurita

Sato

et al. 2009

Circ J

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subgroup of patients with hypertrophic cardiomyopathy (HCM) is at a high risk of having ventricular tachycardia and/or ventricular fibrillation. The implantable cardioverter-defibrillator (ICD) is widely recognized as the most effective and essential therapy for this patient population. [1][2][3] It has been demonstrated that both appropriate and inappropriate ICD discharges are frequently observed in HCM patients, 1-3 and this might impair qualityof-life as well as reduce battery longevity. Class III antiarrhythmic agents such as amiodarone have the potential for reducing ICD shocks 4 and might improve patients' prognosis. Furthermore, class I agents are also used in HCM patients to control atrial fibrillation or reduce the pressure gradient in the left ventricular (LV) outflow tract or midventricle when an obstruction is present. [5][6][7] The combined use of antiarrhythmic agents and an ICD in patients with HCM, and the larger volume of myocardium (caused by hypertrophy of the left ventricle) might result in a high defibrillation threshold (DFT). However, the predictors of a high DFT in patients with HCM have not been fully characterized. Thus, the purpose of this retrospective study was to evaluate the factors causing a high DFT in patients with HCM and ventricular tachycardia/ventricular fibrillation. Methods Study SubjectsThe study population consisted of 23 consecutive patients with an established diagnosis of HCM who underwent initial implantation of an ICD with a standard transvenous lead system at the National Cardiovascular Center from 1997 through to 2005. ICDs were implanted for secondary prevention in 20 of 23 patients, defined by clinical sustained ventricular tachyarrhythmia or resuscitation from sudden cardiac death. HCM was diagnosed on the basis of echocardiographic criteria defined as the presence of LV hypertrophy in the absence of other causes of hypertrophy. These patients also met the definition and classification proposed by the 1995 World Health Organization/International Society and Federation of Cardiology Task Force. 8 All defibrillation leads were implanted by a left cephalic vein cutdown and positioned in the right ventricular apex. No patient had any prior pacemaker implantation, and 2 had permanent atrial fibrillation. Patients who were diagnosed with HCM who progressed to a dilated phase of HCM were excluded from the study. ICD Implantation and DFT TestingThe following ICD models were implanted: 7220C (n= 1), 7223Cx (n=6), 7227Cx (n=2), 7229Cx (n=5), 7271Cx (n=1), and 7273Cx (n=5), manufactured by Medtronic, Inc (Minneapolis, MN, USA); and the 1861 (n=3) manufac- QRS Prolongation is Associated With High Defibrillation Thresholds During Cardioverter-Defibrillator Implantations in Patients With Hypertrophic CardiomyopathyTakayuki Nagai, MD; Takashi Kurita, MD; Kazuhiro Satomi, MD; Takashi Noda, MD; Hideo Okamura, MD; Wataru Shimizu, MD; Kazuhiro Suyama, MD; Naohiko Aihara, MD; Junjiro Kobayashi, MD*; Shiro Kamakura, MD Background: Although high defibrillation threshold (DFT) is a...

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“…A minimum of 224 defibrillation/conversion trials in each of the 5 groups was calculated to assure an 80% power to detect a 4% reduction in defibrillation efficacy from an expected control rate of 99% using a one-sided test (based on data from the Low-Energy Endotak Trial [LEET] study 15 ). Data from each of the 3 follow-up periods was pooled to achieve adequate power for this end point.…”

Section: Discussionmentioning

confidence: 99%

“…Because the conversion success rates for spontaneous episodes were expected to be lower than those required to induce VF, a second sample size of 367 episodes per group was computed based on 80% power to detect a 4% reduction in conversion from an expected control rate of 97% (based on data from the LEET study 15 ). Assuming an episode occurrence rate of 1.6 episodes per patient per 2-year follow-up period and an expected attrition rate of 15% per year, a minimum of 638 patients were required for enrollment.…”

Section: Discussionmentioning

confidence: 99%

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Efficacy and Temporal Stability of Reduced Safety Margins for Ventricular Defibrillation

et al. 2002

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Background-Traditionally, a safety margin of at least 10 J between the maximum output of the pulse generator and the energy needed for ventricular defibrillation has been used because lower safety margins were associated with unacceptably high rates of failed defibrillation and sudden cardiac death. The Low Energy Safety Study (LESS) was a prospective, randomized assessment of the safety margin requirements for modern implantable cardioverter-defibrillator (ICD) systems. Methods and Results-A total of 636 patients undergoing initial ICD implantation with a dual-coil lead and active pulse generator were evaluated. The defibrillation threshold (DFT) and enhanced DFT (DFTϩ and DFTϩϩ) were measured using a modified step-down protocol. Conversion testing of induced ventricular fibrillation before discharge, at 3 months, and at 12 months was performed in all 392 patients, as was randomization to chronic programming at either 2 steps above DFTϩϩ or maximal output in all patients. The induced ventricular fibrillation data had conversion success rates of 91.4%, 97.9%, 99.1%, 99.6%, and 99.8% for safety margins of 0, 1, 2, 3, and 4 steps above the DFTϩϩ, respectively. A margin of 4 to 6 J was adequate to maintain high conversion success over time (98.9% before discharge versus 99.2% at 12 months; PϭNS). Over a mean follow-up of 24Ϯ13 months, conversion of spontaneously occurring ventricular tachyarrhythmias Ͼ200 bpm was identical (97.3%), despite a safety margin difference of 5.2Ϯ1.1 J for the 2-step group versus 20.8Ϯ4.2 J for maximal output. Conclusions-With a rigorous implantation algorithm, a safety margin of about 5 J is adequate for safe implantation of modern ICD systems.

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Safety and efficacy of implantable defibrillator therapy with programmed shock energy at twice the augmented step-down defibrillation threshold: results of the prospective, randomized, multicenter low-energy endotak trial

Cited by 32 publications

References 23 publications

Assessment of Efficacy and Necessity of Routine Defibrillation Threshold Testing in Patients Undergoing Implantable Cardioverter-Defibrillator (ICD) Implantation

Assessment of Efficacy and Necessity of Routine Defibrillation Threshold Testing in Patients Undergoing Implantable Cardioverter-Defibrillator (ICD) Implantation

QRS Prolongation is Associated With High Defibrillation Thresholds During Cardioverter-Defibrillator Implantations in Patients With Hypertrophic Cardiomyopathy

Efficacy and Temporal Stability of Reduced Safety Margins for Ventricular Defibrillation

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