Atrial fibrillation is associated with sudden cardiac death: a systematic review and meta-analysis

Recent studies suggest that atrial fibrillation (AF) is associated with increased cardiovascular risk and mortality including sudden cardiac death (SCD). According to the Cardiovascular Heath Study cohort, the incident rate of SCD was higher in the AF population (2.9 per 1000 per year) compared with non-AF controls (1.3 per 1000 per year). In this study, we performed a systematic review and meta-analysis to explore the association between AF and SCD. We comprehensively searched the databases of MEDLINE and EMBASE from inception to January 2017. Included studies were published prospective or retrospective cohort studies that compared the risk of developing SCD, defined by World Health Organization's criteria, in AF patients versus non-AF patients. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate the risk ratios and 95% confidence intervals. Twenty-seven studies from January 1991 to February 2017 involving 8401 AF patients and 67,608 non-AF controls were included in this meta-analysis. Compared with controls, AF patients had a significantly higher risk of SCD in overall analysis (pooled risk ratio = 2.04, 95% confidence interval: 1.77-2.35, p < 0.01, I (2) = 42.66) as well as subgroups of general population studies, previous myocardial infarction or coronary artery disease, heart failure, hypertrophic cardiomyopathy (HCM), Brugada syndrome, and patients with either a pacemaker or implantable cardioverter defibrillator (ICD). In subgroup analysis of multivariate-adjusted studies, AF also had a significantly higher risk of SCD (pooled risk ratio = 2.22, 95% confidence interval = 1.59-3.09, p < 0.01, I (2) = 73.95). Incident rate of SCD in AF was 2-fold higher than controls but not statistically significant (pooled rate ratio = 2.06, 95% confidence interval = 0.66-7.53, p = 0.292, I (2) = 88.58). Our meta-analysis demonstrates a statistically significant increased risk of SCD with AF in the general population and in those with previous myocardial infarction, coronary artery disease, heart failure, HCM, Brugada syndrome, and an implanted rhythm device.