Atrial Fibrillation and Sudden Cardiac Death

Several recent observational studies have shown an association between AF and SCD. In the Cardiovascular Health Study, the unadjusted incidence of SCD was 12 per 1,000 person-years in those with AF versus 3.8 per 1,000 person years in those without AF. Following adjustment, AF remained associated with an increased hazard of SCD (hazard ratio [HR]: 2.14 [95% confidence interval (CI): 1.60 to 2.87]) (4). Findings in a validation cohort of individuals ages 45 to 64 were similar (4). In the LIFE (Losartan Intervention for Endpoint) study, hypertensive patients with left ventricular hypertrophy and new-onset AF were observed to have a more than 4-fold increased risk of SCD after adjustment for multiple factors, including heart failure (HF) (HR: 4.69 [95% CI: 2.96 to 7.45]) (5). Finally, new-onset AF has also been associated with an increased risk of malignant arrhythmias following myocardial infarction (6). It is plausible that AF independently contributes to the risk of SCD, and potential mechanistic explanations include: 1) genetic or other propensity favoringfibrillation in the ventricles