Long-term prognosis in recipients of implantable cardioverter- defibrillators for secondary preventions in Taiwan - A multicenter registry study

Background: The use of an implantable cardioverter-defibrillator (ICD) has a proven capacity to prevent sudden cardiac death (SCD), and can also improve survival duration in well-selected patients. The goal of the present study was to investigate the long-term prognosis and predictors of mortalities among ICD recipients in Taiwan. Methods: From 1998 to 2009, 238 consecutive patients who experienced SCDs or life-threatening ventricular tachyarrhythmias without correctable causes and received ICD implantations in 3 medical centers (Taipei, Taichung and Kaohsiung Veterans General Hospital) were enrolled in this study. The clinical endpoint was defined as the occurrence of all-cause mortality during the follow-up. Results: The mean age of the patientswas 63.0 ± 15.3 years, and 76.5% of them were male. Ischemic cardiomyopathy was the leading cause for the ICD implantations (39.1%). During the mean follow-up duration of 36.8 ± 29.8 months, there were 48 patients (20.2%) who died. Patients with structural heart diseases had a higher mortality rate than those without such diseases. Additionally, old age, low left ventricular ejection fraction (LVEF) and a history of diabetes mellitus (DM) were significant predictors of mortality. The optimal cutoff values for age (70 years) and LVEF (40%) in predicting mortality were further identified using the receiver operating characteristic curves. Conclusions: Based on the ICD registry from 3 medical centers in Taiwan, the annual mortality rate was around 6.6% and was higher in those patients with structural heart diseases. We observed that old age, low LVEF and a history of DM were significant predictors of mortality.