Abstract 18727: Incidence and Clinical Predictors of Late Atrioventricular Conduction Recovery Among Patients Requiring Pacemaker for Complete Heart Block After Cardiac Surgery

Background: The incidence and clinical predictors of atrioventricular (AV) conduction recovery among patients requiring pacemaker (PM) for complete heart block (CHB) after cardiac surgery are unknown. Methods: Consecutive patients receiving PM for new CHB following cardiac surgery at a high-volume US center from 2000-2014 were evaluated, excluding biventricular PM and PM implanted after the index surgical hospitalization. The primary outcome was AV nodal conduction recovery, defined as a reduction in ventricular pacing to 1 month post-implant. Multi-variable analysis was performed via logistic regression. Results: 326 patients (66 ± 14 years, 57% male) were retained over 4.2 ± 4.1 years follow-up. Late AV conduction recovery occurred in 11.4% of patients (n = 37). The median ventricular pacing requirement for patients with recovery decreased from 96% at implant to 6% at 1 month and 0% at 6 months. Recovery was less common for patients with prolonged pre-operative conduction, including PR (181 ± 34 msec recovery vs. 198 ± 57 msec none, ρ=0.03) and QRS (103 ± 22 msec recovery vs. 118 ± 28 msec none, ρ 200 msec and QRS>120 msec demonstrated recovery (n = 45, 14%). In multi-variable analysis, only female gender (HR 0.38, ρ=0.01), tricuspid valve surgery (HR 0.30, ρ=0.03), and transient intact post-operative AV conduction (HR 0.33, ρ=0.03) were independently associated with recovery. There were otherwise no differences by surgery subtype nor timing from surgery to PM implant (Table 1). Conclusions: Late AV conduction recovery is uncommon among patients requiring PM for CHB following cardiac surgery, particularly with prolonged pre-operative AV conduction. Only female gender, tricuspid valve surgery, and transient intact post-operative AV conduction were independently associated with recovery.