Predictors of sustained ventricular arrhythmia episodes in patients with primary ICD indication: male gender and AF in primary ICD prophylaxis.

AIMS: Implantable cardioverter-defibrillators (ICD) reduce mortality in patients with severely impaired left ventricular function. In randomized studies, female patients are underrepresented and data on ICD therapy is limited. Atrial fibrillation (AF) is a determinant of poor prognosis but has not been consistently evaluated. We evaluated the risk factors for the occurrence of ventricular arrhythmia episodes in patients with primary ICD prophylaxis.
METHODS: Consecutive patients after ICD implantation for primary prophylaxis were followed. During follow-up, detected sustained episodes of ventricular arrhythmia were documented. Multivariate analysis controlled for propensity score was used to evaluate the correlation between gender, history of AF, and the occurrence of ventricular arrhythmia episodes.
RESULTS: A total of 400 patients (19.8% female; n = 79) were included. During follow-up, 64 patients (16%) had appropriate ICD therapy episodes. Men (18%) had significantly more often episodes than women (8%; p = 0.025). Patients with a history of AF (102, 25.5%) had significantly more often episodes (30%) compared to patients without a history of AF (11%; p < 0.001). In a multivariate model, only gender (p = 0.02) and history of AF (p < 0.001) were significantly associated predictors of the occurrence of appropriate ICD therapies during follow-up. Based on the propensity score model, the adjusted hazard ratio for male gender was 2.7 (p = 0.02) and 2.6 (p = 0.0004) for history of AF.
CONCLUSION: Male gender and history of AF are independent predictors for the occurrence of sustained ventricular arrhythmia in primary ICD prophylaxis. Further studies need to evaluate whether history of AF in female patients might be an indicator for higher risk of sudden cardiac arrhythmic death.