BACKGROUND Conducting system defects are common in patients with aortic valve disease. Aortic valve replacement may result in further conduction abnormalities and necessitate permanent pacemaker implantation (PPM). We sought to identify the contemporary incidence and predictors for early postoperative PPM in patients undergoing isolated aortic valve replacement. METHODS Data were analyzed from 354 consecutive patients undergoing isolated aortic valve replacement at a referral cardiac unit during a 30-month period; data were unavailable on 4 patients and a further 8 had undergone preoperative PPM. Results for the remaining 342 patients (97%; mean age, 67 +/- 14 years), of whom 212 were males, are presented. The major indications for aortic valve replacement were valvular stenosis (n = 224), regurgitation (n = 70), or infective endocarditis (n = 25). Preoperative conducting system disease was present in 26% of patients. RESULTS In-hospital mortality was 1.8% (6 of 342 patients). Postoperatively 29 patients (8.5%) required early PPM, of which 26 were during the index admission. Patients with preoperative conducting system disease (16% versus 6%; p = 0.004) and valvular regurgitation (16% versus 7%; p = 0.01) were more likely to require PPM as opposed to those without. Preoperative conducting system disease was the only independent predictor of PPM (p < 0.01); the relative risk of PPM requirement in this group was 2.88 (95% confidence interval, 1.31 to 6.33). CONCLUSIONS Permanent pacemaker implantation requirement after aortic valve replacement is a common occurrence, and should be discussed as part of the preoperative consent process. Preexisting conducting disease and preoperative aortic regurgitation were predictors of PPM requirement.