The best timing for permanent pacemaker implantation (PPMI) for complete atrioventricular block (AVB) after cardiac surgery is still unknown. We aimed to describe the predictors of complete AVB after cardiac surgery, and the best timing for PPMI in this situation.

All patients who underwent surgery in our institution during 17 month were screened in a prospective observational cohort study.

In total, 1200 patients were enrolled, 6% developed complete AVB and 2.8% required PPMI. 3 of the AVB patients (4.2%) underwent isolated CABG, 6 (8.3%) mitral valve repair, 19 (26.4%) mitral valve replacement and 44 (61.1%) aortic valve replacement. 34 of them (47.2%) required PPMI in a mean range of 8 days after surgery. Thirty AVB-patients (41.7%) recovered sinus rhythm within a mean period of 3 days. Late AVB were observed until day 8 post-surgery. By multivariate analysis, positive predictors of AVB were: older age (P=0.023), female sex (P=0.005), endocarditis (P=0.01), and aortic valve replacement (P<0.001). There were no identified risk factors of recovering; the two groups were similar (Table 1, Fig. 1).

AVB requiring transient pacing occurred in 6% of the patients and 2.8% will require PPMI. Half of the non-implanted patients recover within 3 days, which suggest that we could decide permanent pacing before the 7th postoperative day.