Extremely Late Complete AV Block After TAVR: ECG Clues and Correction With Left Bundle Branch Pacing

Transcatheter Aortic Valve Replacement (TAVR) carries a notable risk of conduction system injury. While most atrioventricular (AV) blocks occur early, predictors of late-onset AV block and its latest timing remain uncertain.

A 63-year-old man who developed complete AV block 17 months after TAVR (Evolut-R 29 mm). Serial electrocardiograms showed progressive warning signs: left anterior fascicular block at one month, complete left bundle branch block (LBBB) with first-degree AV block at one year, and, ultimately, complete AV block. Electrophysiological study demonstrated AH and HV intervals of 75 ms and 78 ms, respectively. Prolonged ambulatory monitoring revealed intermittent high-grade AV block. The patient underwent left bundle branch pacing (LBBP), which provided physiologic ventricular activation and corrected the conduction abnormalities; symptoms resolved and pacing parameters remained stable on follow-up.

Complete AV block can present extremely late after TAVR. Even subtle ECG abnormalities should be regarded as warning signs and prompt prolonged rhythm surveillance. LBBP is a physiologic pacing strategy that can both ensure reliable pacing and restore ventricular conduction.