Patients with a high defibrillation threshold: Clinical characteristics, management, and outcome

Pinski, Sergio L.; Vanerio, Gabriel; Castle, Lon W.; Morant, Victor A.; Simmons, Tony W.; Trohman, Richard G.; Wilcoff, Bruce L.; Maloney, James D.

doi:10.1016/0002-8703(91)90763-8

Cited by 72 publications

(40 citation statements)

References 19 publications

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“…14,15 Therefore, it is even more important to predict an increase in DFT before ICD implantation in patients with HCM. Previous studies have described several clinical factors that are associated with a high DFT, such as LV dilatation, 16 body size, 16 decreased LV ejection fraction, 17 administration of antiarrhythmic drugs (class I; flecainide, 18 mexiletine 19,20 etc, class III; amiodarone [21][22][23] ), myocardial ischemia, 24-27 the ventricular fibrillation duration, 28,29 and LV mass. 23,30,31 Among these factors possibly associated with high DFTs, only the LV ejection fraction was found to be a univariate predictor of a high DFT in the present study.…”

Section: Discussionmentioning

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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Section: Discussionmentioning

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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“…4 47; and the waveforM24849 and direction50 of the delivered shock. Because of the potential adverse consequences of an elevated defibrillation threshold,1"5",52…”

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confidence: 99%

Clinical characteristics and outcome of patients with high defibrillation thresholds. A multicenter study.

et al. 1992

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BACKGROUND Successful defibrillation by an implantable cardioverter-defibrillator (ICD) depends on its ability to deliver shocks that exceed the defibrillation threshold. This study was designed to identify clinical characteristics that may predict the finding of an elevated defibrillation threshold and to describe the outcome of patients with high defibrillation thresholds. METHODS AND RESULTS The records of 1,946 patients from 12 centers were screened to identify 90 patients (4.6%) with a defibrillation threshold greater than or equal to 25 J. Excluding three patients who received ICDs that delivered greater than 30 J, there were 81 men and six women with a mean age of 59.5 +/- 10.1 years, a mean left ventricular ejection fraction of 0.32 +/- 0.14, and a 76% prevalence of coronary artery disease. Sixty-one patients (70%) were receiving antiarrhythmic drugs, and 45 (52%) were receiving amiodarone. Seventy-one patients (82%) received an ICD. Death occurred in 27 patients--19 of the 71 (27%) with an ICD (eight arrhythmic), and eight of the 16 (50%) without an ICD (four arrhythmic). Actuarial survival for all patients at 5 years was 67%. Actuarial survival rates at 2 years for patients with and without an ICD were 81% and 36%, respectively (p = 0.0024). Actuarial survival at 5 years for the ICD patients was 73%; no patient without an ICD has lived longer than 32 months. Actuarial survival free of arrhythmic death in the ICD patients at 5 years was 84%. Although the only variable to predict survival was ICD implantation (p = 0.003), it is entirely possible that in this retrospective analysis, clinical selection decisions to implant or to not implant an ICD differentiated patients destined to have better or worse outcomes, respectively. CONCLUSIONS Antiarrhythmic drug use may be causally related to the finding of an elevated defibrillation threshold. When patients with high defibrillation thresholds receive an ICD, arrhythmic death remains an important risk (42% of deaths in these patients were arrhythmia related, with 16% actuarial incidence at 5 years). Vigorous testing to optimize patch location can potentially benefit patients by enhancing the margin of safety for effective defibrillation.

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“…Defibrillation threshold is defined as the lowest energy required for successful defibrillation. Many factors have been implicated as causes of increased defibrillation threshold: the technical characteristics of the leads and the device [4], waveform [5] and direction of the delivered shock [6], amplitude of the ventricular fibrillation waveform [7], the underlying cardiac disease [8], drug therapy [9,10], body weight [11], gender and species [11], duration of ventricular fibrillation before the internal shock is delivered [12], metabolic factors (adenosine [13], acidbase balance, hypoxia) and the time that the leads have been in place [14].…”

Section: Discussionmentioning

confidence: 99%

Influence of anaesthesia on defibrillation threshold

Moerman¹,

Herregods

Tavernier³

et al. 1998

Anaesthesia

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SummaryInternal cardioverter-defibrillator implantation can be performed under local or general anaesthesia. Whether the technique of general anaesthesia influences the defibrillation threshold remains a matter of debate. We therefore compared, in a prospective, randomised clinical study, the effect of intravenous anaesthesia using propofol with inhalational anaesthesia using isoflurane on the defibrillation threshold in 68 patients scheduled for transvenous single-lead internal cardioverter-defibrillator implantation. Defibrillation threshold was measured at implantation and at device testing 1 week and 1 month after implantation. Patients acted as their own controls. Neither the anaesthetic technique nor the duration of anaesthesia was associated with significant changes in the defibrillation threshold. We conclude that in this group of high-risk patients, both types of anaesthesia are acceptable techniques for internal cardioverter-defibrillator implantation and testing.

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Patients with a high defibrillation threshold: Clinical characteristics, management, and outcome

Cited by 72 publications

References 19 publications

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

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

Clinical characteristics and outcome of patients with high defibrillation thresholds. A multicenter study.

Influence of anaesthesia on defibrillation threshold

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