Heart rhythm O2 · 2026
Peak QRS/T ratio and the spatial ventricular gradient differentiate acute vs chronic left bundle branch block after transcatheter aortic valve replacement.
СтатьяНазвание и аннотация: Перевод в очереди
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Waks Jonathan W, Poulin Marie-France, Tung Patricia, Stabenau Hans F, Haouzi Alice, Clarke John-Ross D, Zimetbaum Peter, d'Avila Andre, Ultimo Beatie, Guibone Kimberly A, Kiernan Katherine, Medline Alexandra, Peters Nicholas S, Sau Arunashis, Ng Fu Siong, Kramer Daniel B, Shvilkin Alexei, Laham Roger J, Buxton Alfred E
Аннотация
BACKGROUND: Differentiating chronic from acute left bundle branch block (LBBB) is useful in various cardiac disorders. Peak QRS/T 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.
OBJECTIVE: This study aimed to validate the QRS/T 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 from acute LBBB.
METHODS: This was a post hoc analysis of a prospective, observational, single-center TAVR study. After TAVR, patients were classified as acute (new <24 hours) or chronic/preexisting LBBB. Electrocardiograms were transformed into vectorcardiograms, and peak QRS/T ratio and SVG were calculated. Sensitivity, specificity, and area under the receiver-operating curve (AUROC) assessed how QRS/T ratio and SVG differentiated chronic from acute LBBB.
RESULTS: Of 409 patients, 21 had preexisting, and 53 had acute/new LBBB. Patients with chronic LBBB had a higher peak QRS/T ratio than patients with acute LBBB (median 3.8 vs 2.2; P < .0001). 3-dimensional SVG vectors significantly differed between chronic and acute LBBB (joint P < .0001), due to differences in the anterior/posterior (Z) direction, (SVGz): median 43.4 vs -14.2 mV·ms, P < .0001, for chronic vs acute LBBB, respectively. A peak QRS/T ratio of ≥2.7 and an SVGz of ≥15 mV·ms had 100% sensitivity, 98.1% specificity, and an AUROC of 0.991 for chronic LBBB. Over long-term follow-up, patients transitioned from acute to chronic LBBB vectorcardiographic phenotype.
CONCLUSION: Peak QRS/T ratio and SVG differentiate chronic from acute LBBB in post-TAVR patients with 100% sensitivity, 98% specificity, and an AUROC of 0.99.
OBJECTIVE: This study aimed to validate the QRS/T 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 from acute LBBB.
METHODS: This was a post hoc analysis of a prospective, observational, single-center TAVR study. After TAVR, patients were classified as acute (new <24 hours) or chronic/preexisting LBBB. Electrocardiograms were transformed into vectorcardiograms, and peak QRS/T ratio and SVG were calculated. Sensitivity, specificity, and area under the receiver-operating curve (AUROC) assessed how QRS/T ratio and SVG differentiated chronic from acute LBBB.
RESULTS: Of 409 patients, 21 had preexisting, and 53 had acute/new LBBB. Patients with chronic LBBB had a higher peak QRS/T ratio than patients with acute LBBB (median 3.8 vs 2.2; P < .0001). 3-dimensional SVG vectors significantly differed between chronic and acute LBBB (joint P < .0001), due to differences in the anterior/posterior (Z) direction, (SVGz): median 43.4 vs -14.2 mV·ms, P < .0001, for chronic vs acute LBBB, respectively. A peak QRS/T ratio of ≥2.7 and an SVGz of ≥15 mV·ms had 100% sensitivity, 98.1% specificity, and an AUROC of 0.991 for chronic LBBB. Over long-term follow-up, patients transitioned from acute to chronic LBBB vectorcardiographic phenotype.
CONCLUSION: Peak QRS/T ratio and SVG differentiate chronic from acute LBBB in post-TAVR patients with 100% sensitivity, 98% specificity, and an AUROC of 0.99.