Evaluation of Acute Electrical and Hemodynamic Improvement During Left Bundle-Branch Area Pacing Modalities for Resynchronization Therapy.
Yanling Su, Ziqing Yu, Zilong Xiao et al.
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In 30 seconds
This prospective, within-subject physiological study assessed acute electrical and hemodynamic responses to four pacing modalities in 24 patients with heart failure with reduced ejection fraction and left bundle-branch block undergoing cardiac resynchronization therapy implantation. Left bundle-branch area pacing narrowed QRS duration compared with right ventricular septal pacing. At the atrioventricular interval that maximized systolic blood pressure, selective left bundle-branch pacing produced the largest reported improvement (ΔSBP 16.3±5.2 mm Hg), exceeding left ventricular septal and nonselective left bundle-branch pacing. The interval maximizing blood pressure improvement was consistently shorter than the interval yielding the narrowest QRS.
Key findings
- QRS duration was 114.0±16.8 milliseconds with nonselective and 118.4±14.1 milliseconds with selective left bundle-branch pacing, versus 144.4±27.6 milliseconds with right ventricular septal pacing (all P <0.01).
- At the hemodynamic-optimal atrioventricular interval, selective left bundle-branch pacing improved systolic blood pressure by ΔSBP 16.3±5.2 mm Hg, versus 13.5±6.2 mm Hg with left ventricular septal and 12.8±6.3 mm Hg with nonselective pacing (all P <0.05).
- Across pacing modalities, the interval maximizing ΔSBP was shorter than the interval minimizing QRS duration by a mean of 18-29 milliseconds.
Why it matters
The findings show that electrical narrowing and acute hemodynamic improvement do not necessarily peak at the same atrioventricular interval. This distinction may matter when interpreting electrical optimization during resynchronization, because the interval associated with the greatest measured blood pressure response was shorter than the one producing the narrowest QRS. The study also identifies differences in acute response among left bundle-branch area pacing modalities.
What to keep in mind
The study included 24 patients and assessed acute physiological responses during implantation; the abstract does not report longer-term clinical outcomes.