Long-term results of cardioverter defibrillator implantation in patients with malignant ventricular tachyarrhythmias

OBJECTIVES
Implantable cardioverter defibrillator (ICD) is the most effective treatment for the prevention of sudden death in patients with ventricular tachycardia (VT) or ventricular fibrillation (VF). We retrospectively evaluated the long-term results of patients who had undergone cardioverter defibrillator implantation during the past six years.
STUDY DESIGN
The study included 70 consecutive patients (63 men, 7 women; mean age 64.6±8.5 years) who received treatment with a dual-chamber (n=6) or single-chamber (n=64) ICD. Data on demographic and clinical features, echocardiographic left ventricular ejection fractions, ICD indications, clinical course, ICD performance, and medications were derived from the records of our electrophysiology laboratory. The mean follow-up period was 3.1±1.3 years.
RESULTS
Mortality occurred in 10 (14.3%) patients due to sudden arrhythmic death (n=2), noncardiac (cerebrovascular accident, respiratory arrest) causes (n=2), and cardiac (congestive heart failure) causes (n=6). No tachycardiac episodes were detected in 20 patients (28.6%). Forty-two patients had 631 spontaneous sustained VT episodes, for which 1,188 attempts of antitachycardia pacing (ATP) were made (mean 1.9 ATP). The large majority of sustained VT episodes (n=535, 84.8%) were successfully terminated by ATP, while the rest (n=96, 15.2%) required cardioversion. Defibrillation was successful in all the VF episodes (n=160). There were 11 inappropriate interventions in five patients (7.1%), all of whom had a single-chamber ICD. Eleven patients (15.7%) required replacement. According to the New York Heart Association (NYHA) functional class assessment, 12 patients with NYHA III had a significantly greater number of episodes (p=0.019).
CONCLUSION
Our results show that ICD is successful in terminating ventricular tachyarrhythmias either by ATP or shock treatment with high efficacy and safety.