ACE inhibitors as antifibrotic agents in atrial fibrillation: potential relevance in cardiac surgery

Regarding the omission of ACE inhibitors or angiotensin II receptor antagonists before cardiac surgery [1] one should consider the potential beneficial effect of ACE inhibitors as an antifibrotic agent. Postoperative atrial fibrillation (POAF) complicates up to 8% of all non-cardiac surgeries, between 3% and 30% of non-cardiac thoracic surgeries, and between 16% and 46% of cardiac surgeries. POAF has been associated with increased morbidity, mortality, and longer, more costly hospital stays [2]. Given the fact that atrial fibrillation is the most frequent complication following cardiac surgery, recent studies have been reported that ACE inhibitors and angiotensin II receptor blockers are emerging drugs for the prevention of atrial fibrillation by modification of the renin-angiotensinaldosterone system (RAAS) [3]. A meta-analysis of 11 randomized, controlled, parallel-design clinical trials evaluating effect of ACEIs or ARBs on the development of AF revealed that treatment with ACEIs or ARBs reduced the relative risk (RR) of AF in patients with hypertension by 23% and by 11% in patients after myocardial infarction. Reduction in AF was greatest in patients after electrical cardioversion and in patients with heart failure. Overall, inhibition of the RAAS reduced the RR of AF by 19% (RR 0.810, P<0.001, 95% CI 0.759–0.865). However, the effect of ACE inhibitors/angiotensin II receptor blockers on the postoperative rate of atrial fibrillation is undetermined as of yet. The combination of a renin angiotensin system inhibitors (RAS-I) and bepridil might be even superior for the maintenance of sinus rhythm after conversion from persistent atrial fibrillation [4]. Based on these reports the omission of ACE inhibitors or angiotensin II receptor antagonists before cardiac surgery might have an effect on the postoperative rate of atrial fibrillation, which has to be determined in further perspective trials.