Prevention of Inappropriate Shocks in ICD Recipients: A Review of 10,000 Tachycardia Episodes

Background: The efficacy of dual‐chamber ICD arrhythmia classification algorithms is crucial to prevent inappropriate shocks. We report our experience from a meta‐analysis of five prospective clinical studies with inclusion phases ranging between 1997 and 2003. Methods: Dual‐chamber ICD using standard dual‐chamber arrhythmia classification algorithms were implanted in 802 patients (mean age = 64 ± 11 years, 88% men) in 74 medical centers. The ICD indication was secondary prevention in 95% of patients. Supraventricular tachyarrhythmias (SVT) were previously documented in 26% of patients. All spontaneous tachyarrhythmic events documented by the device memories were analyzed by a adjudicating committee. The episodes lasting >12 seconds and/or treated by the ICD were analyzed. Results: Over a mean follow‐up of 302 ± 113 days, 9,690 events were reported. Mean heart rate at the time of events was 131 ± 45 bpm (100–430). Events were classified as oversensing in 1.4%, sinus tachycardia (ST) in 66%, SVT in 13%, slow (