Recovery of atrioventricular conduction after pacemaker placement following cardiac valvular surgery.

BACKGROUND: Atrioventricular block (AVB) occurs commonly after valve surgery, and permanent pacemaker (PPM) implantation is often required. However, the rate and time course of spontaneous recovery of AV conduction in these patients is not known. The goal of this study was to define the rate and risk factors for late high-grade AVB in patients who have PPM implantation for this indication.

METHODS: Serial PPM or defibrillator interrogation data as well as demographic and operative data were reviewed from consecutive patients who had device implantation for AVB following valve surgery. Predictors of late AVB were identified with multiple regression models, and recovery of AV conduction was determined with Kaplan-Meier analyses.

RESULTS: Among 98 patients included in the analysis, 58% (57/98) had evidence of late high-grade AVB, with a mean follow-up of 3.6 years. Of the 57 patients with late AVB after PPM implantation, 44 (77%) displayed pacing dependency. In multivariate analyses, persistent AVB in the immediate postoperative period was the only variable associated with late AVB (odds ratio 5.3, 95% confidence interval [2.1, 13.5], P = 0.0006). Among patients who recovered AV conduction within 1 month of surgery, 26% developed AVB during extended follow-up.

CONCLUSIONS: Approximately 40% of patients who received a PPM for AVB after valve surgery displayed no evidence of high-grade AVB during serial device interrogations. However, simple baseline demographic, operative, and postoperative variables are not sufficiently robust for discriminating those patients with early postoperative AVB who will not need long-term pacing following valve surgery.