Predictors of Pacemaker Dependency in Patients requiring Pacemaker Implantation after Transcatheter Aortic Valve Replacement.

Background
Approximately half of the patients requiring permanent pacemaker implantation after transcatheter aortic valve replacement (TAVR) experience conduction recovery.The predictors of pacemaker dependency remain unclear. The purpose of this study is to determine the factors that play a role in pacemaker dependency in patients requiring pacemakers after TAVR.

Methods
We performed a retrospective study on 275 patients who received either self-expandable or balloon-expandable valves between June 2014 and March 2017. Pacemaker dependency was defined as the presence of a high degree atrioventricular block (second degree and complete heart block), slow (≤30 bpm) or absent ventricular escape rhythm during follow-up pacemaker interrogation.

Results
Twenty-three patients (8.4%) received a new permanent pacemaker (PPM) following TAVR. Twelve patients received pacemakers for complete heart block (CHB) and had adequate follow-up (52.2%) - out of which 7 Patients (58.3%) were pacemaker dependent (PD) while 5 patients (41.7%) were pacemaker non-dependent (PND). The PD patients were significantly older than the pacemaker PND patients; 85.8 ± 4.45 vs 67.6 ± 13.12 (years) (p = 0.006). The mean Society of thoracic surgery (STS) score was higher in the PD group compared to the PND group 5.9 ± 2.6 vs 2.9 ± 1.2 (p = 0.04). The mean QRS duration in the PD group was 136 ± 15 ms compared to 107.8 ± 20.9 ms in the PND group (p = 0.02).

Conclusions
Advanced age, increasing STS Score and increasing QRS duration correlates with persistent pacemaker dependency. Larger studies are needed to confirm these findings.