What is the clinical evidence from this study?

Study design: Observational. Population: Patients with new-onset left bundle branch block (LBBB) after transcatheter aortic valve replacement (TAVR) (n=282). Intervention: Immediate vs delayed new-onset LBBB after TAVR vs. Immediate new-onset LBBB group. Primary outcome: Permanent pacemaker implantation (PPI) within first 2 weeks post-TAVR due to relevant clinical indications (p = 0.19, p=0.19).

What does this research mean for the field?

Delayed new-onset left bundle branch block after transcatheter aortic valve replacement occurs in approximately 12% of patients and is associated with similar mortality and permanent pacemaker implantation rates compared to immediate LBBB, although different ECG parameters predict the need for pacing. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

To characterize the incidence and features of delayed LBBB after TAVR, as well as identify risk factors for permanent pacemaker implantation.

February 21, 2026Open Access

Immediate vs delayed left bundle branch block after transcatheter aortic valve replacement: incidence and risk factors for permanent pacemaker implantation

Key Result

Delayed new-onset LBBB after TAVR occurred in 11.7% and was associated with a numerically higher but not statistically significant PPI rate (21% vs 12.8%, p=0.19) and similar mortality compared to immediate LBBB.

Key Points

To characterize the incidence and features of delayed LBBB after TAVR, as well as identify risk factors for permanent pacemaker implantation.
Screened 1469 consecutive TAVR patients for new onset LBBB
Divided patients into immediate or delayed onset groups based on ECG results
Followed both groups for occurrences of permanent pacemaker implantation and mortality
20.1% of patients developed new-onset LBBB post TAVR
Immediate LBBB was observed in 88.3% of cases, while delayed LBBB occurred in 11.7%
QRS width correlated with PPI need in immediate LBBB; PR prolongation of ≥ 115 ms identified high-risk for PPI in delayed LBBB

Study Design

Type

Observational (n=282)

Structured PICO

Does delayed new-onset LBBB compared to immediate new-onset LBBB after TAVR alter the risk of permanent pacemaker implantation or mortality?

Population

282 patients who developed new-onset left bundle branch block (LBBB) after transcatheter aortic valve replacement (TAVR) out of 1,469 screened consecutive TAVR patients. Exclusions: pre-existing bundle branch block, prior TAVR or surgical aortic valve replacement, pre-existing permanent pacemaker, missing documentation of LBBB post-TAVR, or newly developed right bundle branch block.

Intervention

Delayed new-onset LBBB (first post-TAVR ECG demonstrated narrow QRS and LBBB was documented on subsequent ECGs during hospitalization, median onset day 1.88)

Comparator

Immediate new-onset LBBB (documentation of a new post-TAVR LBBB on the first post-TAVR ECG, onset day 0)

Outcome

Need for permanent pacemaker implantation (PPI) and all-cause mortalityhard clinical

Delayed new-onset LBBB occurs in about 12% of post-TAVR LBBB cases and carries a similar risk of pacemaker implantation and mortality as immediate LBBB, but requires monitoring of PR prolongation rather than QRS duration to predict pacemaker need.

Main Result

Effect estimate: p = 0.19

Absolute Event Rate: 21% vs 12.8%

p-value: p=0.19

Limitations

Retrospective observational design
Small number of delayed LBBB patients and PPI events limiting multivariable analyses
Lack of continuous telemetry data may have missed transient conduction abnormalities
Single center in Israel, limiting generalizability

Abstract

Characteristics of patients with delayed compared to immediate new onset left bundle branch block (LBBB) after transcatheter aortic valve replacement (TAVR) are poorly defined. To describe the incidence and features of patients with delayed post TAVR LBBB as well as risk factors for permanent pacemaker implantation (PPI). 1469 consecutive TAVR patients were screened for the occurrence of new onset LBBB. ECG was performed within 1 week before the procedure, immediately post procedure, and daily thereafter until discharge. According to the immediate post TAVR ECG, patients were divided into 2 groups, immediate and delayed new onset LBBB. Both groups were followed for the occurrence of PPI and mortality. Among patients who underwent TAVR, 296 (20.1%) developed new-onset LBBB, of whom, 282 were included the present study. LBBB occurred immediately after the procedure in 249 patients (88.3%) and was delayed in 33 patients (11.7%). Rates of both early PPI within 2 weeks as well as long term PPI and mortality were comparable between patients with immediate vs. delayed onset LBBB. In patients with immediate LBBB, QRS width correlated with a need for PPI, while in patients with delayed LBBB, PR prolongation of ≥ 115 ms differentiated between patients with and without PPI. The appearance of new onset post TAVR LBBB may be delayed in ~ 12% of patients. These patients exhibit similar rates of PPI need and mortality; however different ECG parameters signify high risk for PPI need among these patients.

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