Background: The first multicenter automatic defibrillator implantation trial (MADIT‐I) was a landmark study that identified a significant reduction in mortality among high‐risk patients with ischemic cardiomyopathy treated prophylactically with an implantable cardioverter defibrillator (ICD), yet the direct and indirect impact of this trial on clinical practice is unknown.

ELLINOR, P.T., et al .: Variability in Implantable Cardioverter Defibrillator Pulse Generator Longevity Between Manufacturers. ICDs are used frequently to treat malignant ventricular arrhythmias. Despite the expanding role of these devices, little is known about the manufacturer variability in the performance of ICD generators. The purpose of this study is to explore the indications for ICD pulse generator replacement and to examine performance differences between the three major manufacturers of ICDs in the United States. The authors performed a retrospective review of ICD pulse generators that were implanted and replaced at Massachusetts General Hospital between February 1998 and March 2002. During the study period, 50 (7%) of the 707 devices in the study cohort were replaced. The most common indication for pulse generator replacement was related to battery performance followed by device recall, upgrade to a dual chamber device, and pulse generator malfunction. After exclusion of the recalled devices, a significantly higher number of pulse generators manufactured by St. Jude Medical (14/229) required replacement for battery depletion or prolonged charge times during the study period compared with devices from Guidant (2/220) or Medtronic (0/273), P = 0.003 and P < 0.0001 , respectively. This difference was attributable to reduced longevity in the Angstrom series of defibrillators. (PACE 2003; 26[Pt. I]:71–75)

Background Implantable cardioverter/defibrillators (ICDs) may reduce sudden tachyarrhythmic death in patients with severe left ventricular dysfunction. It is uncertain whether this improves survival, particularly in patients awaiting cardiac transplantation.Methods and Results The effect of treatment for spontaneous ventricular arrhythmias (ICD [n=59], antiarrhythmic drugs [n=53], or no antiarrhythmic treatment [n=179]) on total mortality and mode of cardiac death was analyzed in 291 consecutive patients evaluated for cardiac transplantation between January 1986 and January 1995. There were 109 deaths (37.4%) (63 [21.6%] sudden, 40 [13.7%] nonsudden, and 6 [2.1%] noncardiac) during mean follow-up of 15 months (range, 1 to 118 months). Baseline clinical variables, medical therapies for heart failure, and actuarial rates of transplantation were similar between treatment groups. Kaplan-Meier sudden death rates were lowest in the ICD group, intermediate in the no antiarrhythmic treatment group, and highest in the drug treatment group throughout follow-up (12-month sudden death rates, 9.2%, 16.0%, and 34.7%, respectively; P=.004). Total mortality and nonsudden death rates did not differ. Cox proportional-hazards model revealed that antiarrhythmic drug treatment was associated with sudden death (relative risk, 2.1; 95% CI, 1.04 to 3.39; P=.04) and ICD was associated with nonsudden death (relative risk, 2.26; 95% CI, 1.12 to 4.62; P=.02).Conclusions Sudden death rates were lowest in patients treated with ICDs compared with drug treatment or no antiarrhythmic treatment. However, although ICDs reduced sudden death in selected high-risk patients with severe left ventricular dysfunction, the effect on long-term survival was limited, principally by high nonsudden death rates.