ACE-Inhibitors and Risk of Atrial Fibrillation after Cardiac Surgery

Atrial fibrillation (AF) frequently occurs after cardiac surgery and antiarrhythmic drugs including ß-blockers may reduce the frequency of postoperative AF. Recently, several studies have demonstrated that the atrial angiotensin system may play an important role as a mediator of atrial remodelling and subsequent susceptibility for AF. However the effect of preoperative use of ACE-inhibitors (ACE-I) on risk reduction of postoperative AF is not known. Therefore, the aim of the current investigation was to study the effect of preoperative ACE-I use on the risk of postoperative AF in patients undergoing cardiac surgery. 213 patients >/= 55 years (123 men, 90 women, mean age 68.6 years, [range 55-85 years]) from the SPPAF (study of prevention of postoperative atrial fibrillation) trial undergoing elective open-heart surgery in the absence of heart failure and significant left ventricular dysfunction were studied in a prospective fashion. Preoperative patients' characteristics, including cardiovascular therapy at baseline and perioperatively, were correlated with the risk of postoperative AF. AF was defined as episodes of more than 5 minutes in duration documented by ECG monitoring. 89 (41.8%) patients had postoperative AF. 24% of patients with and 38% without postoperative AF (p=0.04) used preoperative ACE-I. Patients on preoperative ACE inhibition had a significantly lower risk of postoperative AF compared to non-ACE-I users (31% versus 46.5% respectively, p=0.04; significance persisted after adjustment for age, heart valve surgery, antiarrhythmic drug use, NYHA functional class and ejection fraction). Additionally, advanced age and surgery for heart valve disease increased, and use of antiarrhythmic drugs decreased the risk for postoperative AF by multivariate analysis (p<0.05). Perioperative ACE-I use decreased the rate of postoperative AF in patients undergoing cardiac surgery in the absence of heart failure and significant left ventricular dysfunction.