Outcomes in hypertrophic cardiomyopathy patients with and without atrial fibrillation: a survival meta-analysis

Background: Atrial fibrillation (AF) is a frequent occurrence in patients with hypertrophic cardiomyopathy (HCM). It is associated with worsening symptoms, cardiovascular events, and mortality. We conducted a meta- analysis of studies reporting on mortality in patient with HCM and AF. Methods: We searched PubMed, Medline, Embase, Ovid and Cochrane for studies which reported cardiovascular events and mortality in patients with HCM and AF. Outcome was a composite of cardiac mortality and/or all- cause mortality. Mantel Haenszel odds ratio (OR) or hazard ratio (HR) were calculated using random- effects meta- analysis for the prespecified outcome. Heterogeneity was assessed using I-2 statistics. Results: Six studies met the inclusion criteria. There were 6,858 patients; 1,314 (19%) had history of AF. During a mean follow up that ranged between 4 and 8 years, 405 (30.8%) patients with AF died as compared to 1,011 (18.2%) patients without AF (OR =2.49, 95% CI: 1.85- 3.35, P< 0.00001, I-2=57%). Results persisted with inclusion of studies only reporting specifically on cardiac mortality (OR =2.80, 95% CI: 1.79- 4.39, P< 0.00001, I-2=56%). Also, the mortality difference persisted after exclusion of deaths secondary to stroke in both groups (2 studies, 1,398 patients, OR =2.57, 95% CI: 1.57- 4.20, P=0.0002, I-2=31%). In three studies (5,857 patients); the presence of AF was associated with a pooled HR of 1.66 (95% CI: 1.29- 2.13, P< 0.0001, I-2=41%). Conclusion: Patients with HCM who develop AF have higher risk of mortality and cardiac deaths as compared to HCM patients without AF.