Clinical experience with pacemaker pulse generators and transvenous leads: an 8-year prospective multicenter study.

BACKGROUND: Pacemakers have improved the lives of patients worldwide. Unfortunately, the medical community has had little independent information regarding the performance of these vital medical devices. OBJECTIVES: The purpose of this study was to examine the reasons pacemaker pulse generators and transvenous leads were removed from service. We evaluated the causes and major adverse clinical events associated with device end-of-service life behavior and how they were detected and managed. METHODS: Pulse generator and lead data were entered prospectively using a web-based format. Normal battery depletion was signified by the elective replacement indicator appearing >3 years after implant. Lead failure was a device defect causing pacing, sensing, or fixation malfunction, high threshold, or abnormal impedance. Major adverse clinical events were death, angina, heart failure, syncope, and perioperative surgical complications. RESULTS: From 1998 to 2006, 2,652 pulse generator and 615 leads were removed from service. The average pulse generator was implanted for 7.3 +/- 3.1 years (range <1 day to 26 years). The majority of pulse generators (n = 2,317 [87%]) were replaced for normal battery depletion. Severe and accelerated battery depletion, manufacturers' advisories, and electronic or connector defects accounted for 13% of pulse generator removals. The proportion of pulse generators removed from service as a result of manufacturers' advisories, electronic failure, and housing defects were 4%, 2%, and 1%, respectively. Models with rate response capability had shorter battery longevities than those without rate response capability. Major adverse clinical events due to pulse generator end-of-service life behavior were related to electronic and connector defects, and both normal and severe battery depletion. Median time to lead failure was 7.2 +/- 5.2 years. Insulation defects caused the majority of lead failures, and most of these leads used polyurethane materials. Lead failure was associated with a 16% incidence of major adverse clinical events. No major adverse clinical events occurred when impending lead failure was detected at routine follow-up. Lead extraction was associated with a 5.6% complication rate, including one death. CONCLUSION: Overall pulse generator performance was satisfactory. Differences in battery longevity were observed among models. In some patients, elective replacement indicators signifying normal battery depletion resulted in major adverse clinical events. Pacemaker follow-up effectively identified pulse generator end-of-service life and often detected impending lead failure, thus avoiding major adverse clinical events. Long-term studies are needed to assess chronic lead performance so that appropriate clinical management strategies, including recommendations for lead extraction, can be developed.

Multicenter experience with failed and recalled implantable cardioverter-defibrillator pulse generators.

BACKGROUND: Despite the widespread and growing use of implantable cardioverter-defibrillators (ICDs), little information is available regarding their performance or the impact of advanced pacing functions on ICD reliability and longevity. OBJECTIVES: The purpose of this study was to examine the performance of contemporary ICD pulse generators that failed or were replaced because of manufacturers recalls. METHODS: ICD data were entered prospectively by nine participating centers. ICD pulse generator failure was defined as removal from service because the device was not functioning according to the manufacturer's specifications. A recalled ICD was a normally functioning pulse generator that was replaced as the result of a recall or advisory. RESULTS: From 1998 to 2005, 1,220 ICDs failed and 135 were recalled and replaced. The average implant time of failed ICDs was 4.4 +/- 1.5 years and of recalled ICDs was 1.7 +/- 0.8 years. The average implant time of single- and dual-chamber ICDs with rate responsive or cardiac resynchronization (CRT-D) pacing capabilities was significantly shorter than the average implant time of single- or dual-chamber devices without these features (P <.001). ICDs that provided rate responsive or CRT-D pacing failed earlier because of battery depletion (P <.001) and were significantly more prone to unexpected electronic or housing failure (9% vs 5%, P = .008) and recalls (25% vs 1%, P <.0001). Major adverse events included death (n = 2), failure to convert ventricular tachyarrhythmias (n = 6), and inappropriate shocks (n = 11). CONCLUSION: Based on our analysis of failed and recalled devices, the performance of contemporary ICDs has been adversely affected by premature battery depletion, electronic failure, and manufacturers' recalls. Additional studies are needed to precisely estimate ICD longevity and to determine the incidence of unexpected ICD failure.