Implantable cardioverter defibrillator therapy: ten years experience in a medical center

An implantable cardioverter defibrillator (ICD) is the therapy of choice for survivors of life-threatening ventricular tachyarrhythmias or sudden cardiac death. To date there is little data concerning the clinical features and outcome of ICD therapy among Taiwanese. This study identifies factors related to the outcome of ICD therapy over a ten-year period at this institution.

Forty-nine ICDs were implanted in 46 patients between August 1996 and January 2006. The mean follow-up duration was 32 +/- 21 months. Patient data, primary cardiac diagnosis, presenting cardiac arrhythmia, echocardiographic parameters, hemodynamic indexes, electrophysiologic findings, and follow-up observations were analyzed. The findings were compared to those of the Taiwan ICD Multicenter Registry (TIMR) Study and major secondary prevention ICD trials in the literature.

The patients in this study were comparable to those of TIMR but were younger and had better left ventricular ejection fractions (LVEF) than those in Western countries. Furthermore, higher mortality on follow-up was observed in patients with any of the following: LVEF < 35%, New York Heart Association (NYHA) functional class III or IV, a left atrial dimension > or = 55 mm, a left ventricular end diastolic dimension > or = 75 mm, an end systolic dimension > or = 60 mm, triple vessel disease, a prior anterior myocardial infarction, and amiodarone or diuretic therapy. Patients with structural heart disease other than ischemic heart disease or dilated cardiomyopathy had higher event recurrence rates.

Left ventricular function is a major determinant affecting the outcome in ICD recipients. Aggressive treatment for heart failure is warranted in these patients.