Incidence and predictors of late atrioventricular conduction recovery among patients requiring permanent pacemaker for complete heart block after cardiac surgery

Background: New-onset complete heart block (CHB) commonly complicates cardiac surgery, for which some patients require a permanent pacemaker (PPM). Little is known regarding late atrioventricular (AV) conduction recovery.

Objective: The purpose of this study was to characterize the incidence and predictors of late AV conduction recovery among patients requiring PPM after cardiac surgery.

Methods: Consecutive patients receiving PPM for CHB after cardiac surgery at a high-volume U.S. center from 2000 to 2014 were evaluated. The primary outcome was late AV conduction recovery, defined as a reduction in ventricular pacing requirement to <10% beyond 1 month postimplant. Regression analysis was performed to evaluate predictors of AV recovery.

Results: Among 301 patients evaluated over 4 ± 4 years of follow-up, the incidence of late AV conduction recovery was 12% (n = 37), for whom the median ventricular pacing requirement decreased from 96% at implant to <1% at 6 months and persisted throughout study follow-up. AV recovery was less common when preoperative conduction abnormalities were present, including no recovery among patients with preoperative PR >200 ms and QRS >120 ms (n = 42). Multivariable analysis identified only female sex and transient AV conduction postoperatively as independent predictors of recovery (odds ratio 3.5; P <.01 for each). Neither cardiac surgery subtype nor PPM implant timing postoperatively was significantly associated with recovery.

Conclusion: Late AV conduction recovery is not uncommon after cardiac surgery, occurring in 1 of 8 patients within 6 months postoperatively. Preoperative AV conduction abnormalities were associated with decreased recovery, whereas female sex and transient postoperative AV conduction were associated with increased recovery.