The implantable cardioverter defibrillator in primary prevention

AIMS: To evaluate the outcome of a population implanted with an implantable cardioverter defibrillator (ICD) for primary prevention in terms of mortality, morbidity and appropriate and inappropriate interventions. Secondly, to compare the performances of single-chamber vs. dual-chamber devices. METHODS: We examined all patients with CAD or CMD who received an ICD in primary prevention with at least 6 months of follow-up. For each patient were evaluated, primarily, survival, complications related to the implantation and performance of the device (antitachycardia pacing/shock). RESULTS: Of 193 patients, 163 were men (84.5). Mean age was 64.4 ± 10 years. One hundred and twenty patients (62%) were affected by CAD and 73 (38%) by CMD. The ejection fraction was 26 ± 6%. Fifty-three patients (27.5%) received a dual-chamber ICD, whereas 140 (72.5%) received a single-chamber ICD. There were periprocedural complications in 5.2% of the patients. At a mean follow-up of 49.9 months, 55 patients (28.5%) died. Appropriate interventions were documented in 40 patients (20.7%). In 36 patients (18%), inappropriate interventions occurred. Patients implanted with dual-chamber ICD had an overall mortality of 17% compared to 32.4% for those implanted with single-chamber ICD (P = 0.029). Mortality was higher in patients with CAD (33.9%) (P = 0.032). Among the fatalities, 69% occurred in patients who had an ejection fraction 25% or less at the time of implantation and 31% in patients with an ejection fraction greater than 25% (P = 0.013). CONCLUSIONS: The 4-year survival was 72%. The overall mortality was higher in patients with CAD. More than two-thirds of the deceased had an ejection fraction less than 25%. The dual-chamber ICD patients had a significantly lower mortality rate.