A Systematic Review of Delayed High-Grade Atrioventricular Block After Transcatheter Aortic Valve Implantation.

Background: High-grade atrioventricular block (HGAVB) is common after transcatheter aortic valve implantation (TAVI), often necessitating permanent pacemaker (PPM) implantation. Delayed HGAVB has varying definitions but typically refers to onset 48 hours after TAVI or following discharge and may cause syncope and sudden cardiac death. This review estimates the incidence of delayed HGAVB and identifies limitations of current literature. Methods: A systematic review was performed of the following online databases: Medline, Cochrane, Web of Science, and Scopus. Studies that labelled the outcome of "delayed" or "late" atrioventricular block after TAVI were included; patients with previous PPM or aortic valve surgery were excluded. Initial search yielded 775 studies, which, after screening, was narrowed to 19 studies. Results: Nineteen studies with 14,898 patients were included. Mean age was 81.7 years, and 46.3% were male. Mean Society of Thoracic Surgeons (STS) score was 5.6%, and 31.3% of patients had known atrial fibrillation. The most common access site was transfemoral (84.8%), whereas balloon-expandable valves were used in 62.1%, self-expanding valves in 34.0%, and mechanically expanding valves in 3.9% of cases. The incidence of delayed HGAVB ranged from 1.7% to 14.6%, with significant methodologic heterogeneity noted among the included studies. Conclusions: Delayed HGAVB is a common and potentially serious complication of TAVI, with similar risk factors to acute HGAVB. With a move toward an early discharge strategy post-TAVI, further prospective study of delayed HGAVB is warranted to improve understanding of predisposing factors, incidence, timing, and implications.