JAMA Cardiology Author Interviews A Revised Definition of Left Bundle Branch Block Using Time to Notch in Lead I
Mar 27, 2024
Gaurav A. Upadhyay, MD, and Jeremy S. Treger, MD, PhD discuss a revised definition of left bundle branch block using time to notch in lead I. They explore challenges in defining LBBB, study conduction system pacing, introduce a new criterion for diagnosis, emphasize measuring notches in lead I, and stress the importance of ECGs in diagnosing cardiac conditions.
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Origins of LBBB Criteria Confusion
- Traditional criteria for left bundle branch block (LBBB) originate from early 1900s canine studies with anatomical orientation errors.
- This led to confusion and variability in definitions that still impacts diagnosis today.
Direct Left Bundle Branch Mapping
- Mapping the left bundle branch conduction system requires placing a catheter in the left ventricular septum beneath the aortic valve.
- This allows direct assessment of true conduction block versus delay.
Patient Selection for Study
- The study enrolled patients already undergoing invasive procedures like VT ablations or CRTD implants.
- This enabled safe mapping without additional arterial access risk.