What does this research mean for the field?

Peak QRST ratio and the spatial ventricular gradient (SVG) accurately differentiate chronic from acute left bundle branch block in patients following transcatheter aortic valve replacement. Novelty: ClaimNovelty.CONFIRMATORY. Consensus alignment: ConsensusAlignment.NEUTRAL.

March 3, 2026Open Access

Peak QRST Ratio and the Spatial Ventricular Gradient Differentiate Acute vs Chronic Left Bundle Branch Block after Transcatheter Aortic Valve Replacement

Key Points

Peak QRST ratio indicates significant differences in LBBB types, with a median of 3.8 for chronic and 2.2 for acute.
Using defined thresholds, the QRST ratio and spatial ventricular gradient achieve 100% sensitivity and 98.1% specificity for identifying chronic LBBB.

Structured PICO

Do peak QRST ratio and spatial ventricular gradient differentiate acute from chronic LBBB in post-TAVR patients?

Population

409 post-transcatheter aortic valve replacement (TAVR) patients from a prospective, observational, single-center study, including 21 with preexisting/chronic left bundle branch block (LBBB) and 53 with acute/new LBBB (<24 hours).

Intervention

Electrocardiogram-derived peak QRST ratio and spatial ventricular gradient (SVG) assessment

Outcome

Sensitivity, specificity, and area under the receiver-operating curve (AUROC) for differentiating chronic from acute LBBBsurrogate

Peak QRST ratio and spatial ventricular gradient can highly accurately differentiate acute from chronic LBBB in patients post-TAVR.

Abstract

Abstract:Background Differentiating chronic from acute left bundle branch block (LBBB) is useful in various cardiac disorders. Peak QRST ratio, a measure of cardiac memory, can differentiate chronic from acute LBBB with high sensitivity and specificity, but its utility in post-transcatheter aortic valve replacement (TAVR) patients with LBBB is unclear. Objectives Validate QRST ratio for differentiating chronic/acute LBBB in post-TAVR patients, and assess whether the spatial ventricular gradient (SVG), which integrates 3-dimensional depolarization/repolarization throughout the cardiac cycle, could also distinguish chronic/acute LBBB. Methods Post-hoc analysis of a prospective, observational, single-center TAVR study. Post-TAVR, patients were classified as acute (new Results Of 409 patients, 21 had preexisting, and 53 had acute/new LBBB. Chronic LBBB patients had higher peak QRST ratio than acute LBBB patients (median 3.8 vs 2.2, pConclusions Peak QRST ratio and SVG differentiate chronic from acute LBBB in post-TAVR patients with 100% sensitivity, 98% specificity, and AUROC of 0.99.

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