Renin-angiotensin-aldosterone blockade reduces atrial fibrillation in hypertrophic cardiomyopathy

Objectives: Atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) is associated with increased mortality, mainly mediated by increased thromboembolic events and progressive heart failure. Many studies suggested inhibition of renin-angiotensin-aldosterone system (RAAS) could reduce new AF in various clinical conditions. However, evidence concerning the effects of RAAS inhibitors on AF prevention remains unclear in HCM. Our study is to investigate whether treatment with ACE inhibitors (ACEIs) or angiotensin-receptor blockers (ARBs) could lower the risk of new AF in HCM. Methods: We conducted a retrospective study including subjects diagnosed HCM between January 1997 and December 2013 by using a nationwide database covering almost all Taiwanese from National Health Research Institute. All participants, aged 18 or older, had no ACEIs or ARBs exposure or AF diagnosis before enrolment. Propensity score matching and multivariate Cox hazard regression were employed to estimate the risk of new AF occurrence. Results: Total 18 266 subjects were included in the analysis with median follow-up duration 8.13 years. Patients taking ACEIs or ARBs are associated with lower risk of developing new AF than those without taking neither of medications (3.16% vs 5.65%, relative risk 0.56 (95% CI 0.49 to 0.64), HR 0.572 (95% CI 0.480 to 0.683)). The correlation is more prominent with longer ACEIs or ARBs treatment (HRs from T1 to T3: 0.741, 0.579, 0.337, P<0.001). These results remain consistent after propensity score adjustment. Conclusion: In patients with HCM, lower risk of new AF is observed in patients treated with either ACEIs or ARBs compared with those receiving neither of these medications.