Added Diagnostic Value of Electrophysiological Study in New Onset Left Bundle Branch Block After Transcatheter Aortic Valve Implantation.

BACKGROUND

New-onset left bundle branch block (LBBB) after transcatheter aortic valve implantation (TAVI) is associated with a high risk of conduction disturbances. We evaluated the relationship between post-TAVI electrocardiogram (ECG) parameters and the His-ventricular (HV) interval and assess the diagnostic performance for risk stratification.

METHODS

The Assessment of the Prognosis of Persistent Left Bundle Branch Block (LBBB)After Transcatheter Aortic Valve Implantation (TAVI) by an Electrophysiological and Remote Monitoring Risk-adapted Algorithm (LBBB-TAVI) study was a prospective, multicentre study that included 183 patients with a new-onset LBBB ≥ 24 hours after TAVI. The HV interval was compared with ECG parameters on the day of electrophysiological study. Patients were continuously monitored for atrioventricular block during 12 months, either using a dual-chamber pacemaker or an implantable loop recorder.

RESULTS

On the day of electrophysiological study (median day 3 post-TAVI), mean PR and QRS durations were 224 ± 50 ms and 148 ± 18 ms, respectively. Mean HV interval was 62 ± 14 ms and was weakly correlated with PR (r = 0.19) and QRS (r = 0.26). Adding HV interval ≥ 70 ms to ECG parameters improved the area under the curve from 0.648 to 0.757 (P = 0.031), and reduced the number needed to test from 5.6 to 3.3 in low-risk profile patients (QRS < 150 ms and PR < 240 ms). In the high-risk group (QRS ≥ 150 ms and PR ≥ 240 ms), HV interval ≥ 70 ms increased the positive predictive value from 23% to 62% but reduced the negative predictive value from 85% to 68%. Within this high-risk subgroup, despite HV interval < 70 ms, 28% developed high-grade atrioventricular block vs 57% with HV interval ≥ 70 ms.

CONCLUSIONS

In new-onset LBBB after TAVI, the relationship between HV interval and ECG parameters was weak but clinically relevant. Combining ECG parameters and HV interval improved risk stratification but did not eliminate residual risk, warranting close ambulatory monitoring.