Abstract 3557: The Occurrence of Inappropriate Shocks in ICD-recipients: Comparison of Single-chamber, Dual-chamber and CRT-D
Introduction: To reduce the occurrence of inappropriate ICD shocks, devices are under constant development with improving complex algorithms and extending sensing possibilities. Logically, better tachyarrhythmia discrimination should lead to a reduction of inappropriate shocks per device type. The aim of this study was to assess the occurrence of inappropriate ICD shocks, comparing single-chamber, dual-chamber and Cardiac Resynchronization Therapy Defibrillators (CRT-Ds) in a large population.
Methods: All patients treated with an ICD or CRT-D system between August 1998 and December 2006 at the Leiden University Medical Center were included in the current analysis. During follow-up, all cases of inappropriate shocks were noted. Patient death and device replacement were considered censoring events.
Results: A total of 1568 patients were included with a mean follow-up of 2.9±1.0 years. All patients received a single-chamber ICD (193, 12%), a dual-chamber ICD (827, 53%) or a CRT-D (548, 35%). Two-hundred and five (13%) patients experienced ≥1 inappropriate shock, mostly due to supraventricular tachycardia (76%). Cumulative event rate (Figure⇓) for inappropriate shocks after 4 years was 15.4% [95%CI 9.9%– 20.9%] for single-chamber ICDs, 16.1% [95%CI 13.3%–18.8%] for dual-chamber ICDs and 13.0% [95%CI 9.3%–16.7%] for CRT-Ds. No significant differences were seen in the event rate of inappropriate shocks comparing the three device types (p=0.18).
Conclusion: In a large cohort of ICD-recipients, comparison of the follow-up in patients with a single-chamber ICD, dual-chamber ICD or CRT-D shows no significantly differences in the occurrence of inappropriate shocks.