New ECG Morphologic Criteria for the Identification of Left Bundle Branch Capture

Autores de IIS La Fe

• Óscar Cano Pérez

  Autor

• Carmen Arveras Martínez

  Autor

• Javier Navarrete Navarro

  Autor

• Pablo Jover Pastor

  Autor

• Valero Vicente Soriano Alfonso

  Autor

• Josep Navarro Manchón

  Autor

• María Teresa Izquierdo De Francisco

  Autor

• Joaquín Osca Asensi

  Autor

• 

  Luis Vicente Martínez Dolz

  Autor

Participantes ajenos a IIS La Fe

• Robles, E
• Vijayaraman, P

Grupos

• Grupo de Investigación Clínica y Traslacional en Cardiología

Abstract

BACKGROUND Identification of left bundle branch capture (LBBc) during left bundle branch area pacing remains challenging. OBJECTIVES This study sought to validate the utility of new simple morphologic criteria for the identification of LBBc. METHODS Patients with proven LBBc based on the presence of QRS transition during decremental output pacing were included. The paced V-6 QRS upstroke/downstroke was quantitatively and qualitatively evaluated, and classified as fast or slow, with fast upstroke patterns associated with LBBc and slow upstroke patterns with left ventricular septal capture (LVSc). Additionally, the appearance of a paced QRS downstroke slurring/notching in any lead not previously present during lead penetration and/or an "M" QRS pattern in inferior leads was also considered suggestive of LBBc. Accuracy of these criteria was tested by independent evaluators using exclusively qualitative electrocardiogram morphologic features. RESULTS 115 patients with proven LBBc were included. Mean V-6 QRS upstroke duration during LBBc was significantly shorter than during LVSc (34.6 +/- 10.1 ms vs 63.2 +/- 12.1 ms; P < 0.001). A paced V-6 upstroke/downstroke ratio <1 had a sensitivity and specificity of 0.97 and 0.95 for the identification of LBBc. A slurred/notched QRS downstroke or "M" pattern in inferior leads was present in 91.1% during LBBc in baseline narrow QRS patients with inferior paced QRS axis, with sensitivity and specificity being 0.91 and 0.87, respectively. Using exclusively qualitative criteria, independent evaluators were able to identify the correct capture pattern in 87% of LBBc and 89% of LVSc cases, with diagnostic accuracy being significantly lower among dilated cardiomyopathy patients: 70.4% vs 93%; P = 0.004. CONCLUSIONS Simple electrocardiogram morphologic criteria can accurately identify LBBc during left bundle branch area pacing in patients with baseline narrow QRS and/or without cardiomyopathy.

Copyright © 2025 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Keywords

• conduction system pacing; left bundle branch area pacing; left bundle branch capture; left ventricular sept al capture