Abstract 2434: Long-Term Survival After Termination of Ventricular Tachyarrhythmia by an Implanted Defibrillator in a Primary Prevention Population
BACKGROUND: In patients with reduced left ventricular ejection fraction (LVEF), the implantable cardioverter-defibrillator (ICD) is effective in preventing sudden death by terminating potentially life-threatening ventricular tachyarrhythmias (VA). Little is known about the risk of all-cause mortality after termination of VA, and some have hypothesized that VA is a harbinger of impending death. Therefore, we assessed long-term survival after termination of VA in a real life primary prevention population with reduced LVEF and ICDs.
METHODS: Patients with LVEF ≤ 35 % who received an ICD at our institution (1995–2005) were identified, excluding patients who presented with cardiac arrest or sustained ventricular tachycardia. Survival after first appropriate ICD therapy for VA was assessed by the Kaplan-Meier method with outcomes ascertained from the social security death index.
RESULTS: We identified 656 consecutive patients with LVEF ≤ 35 who received an ICD for primary prevention (79 % male, median age 66 years, median LVEF 23 %, 80 % with ischemic etiology), of which 153 (23 %) had appropriate ICD therapy. Cumulative survival after first ICD therapy for VA was 90, 84, 64, and 24 % at 1, 2, 5, and 10 years respectively. Similarly, cumulative survival after first ICD therapy for rapid VA (cycle length 260 ms or less, n = 59) was 88, 83, 61, and 39 % at 1, 2, 5, and 10 years respectively.
CONCLUSION: In routine clinical practice, patients with reduced LVEF, and ICDs for primary prevention survive for several years after ICD termination of VA including potentially life-threatening rapid VA. The potential benefit of terminating such VA does not appear to be offset by impending death.