Rate-related QRS morphological changes in left bundle branch pacing: A case report
Yajun Ji1, Yubin Zhang2, Kenneth A Ellenbogen3
1Department of Cardiology, Haining People's Hospital, Haining Branch, The First Affiliated Hospital, Zhejiang University School of Medicine, Haining, China.
Journal of Electrocardiology
|November 11, 2021
Summary
Permanent left bundle branch pacing (LBBP) is feasible and beneficial. Pacing rate changes significantly impacted LBBP QRS morphology, demonstrating retrograde conduction effects on the electrocardiogram.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Pacing
Background:
- Permanent left bundle branch pacing (LBBP) is an established technique with potential clinical benefits.
- Typically, LBBP results in a paced QRS morphology resembling a right bundle branch block (RBBB) due to early left ventricular activation.
Observation:
- A case study involving a 71-year-old man with sick sinus syndrome and a dual-chamber pacemaker (LBBP) is presented.
- A transition from non-selective to selective LBBP was observed.
- A notable change in the R' wave amplitude in lead V1 was recorded during this transition.
Findings:
- A decrease in the R' wave was observed during the transition to selective LBBP.
- Increasing the pacing rate led to an increase in the R' wave amplitude in lead V1.
- The pacing rate was found to influence the QRS morphology, ultimately manifesting as a complete RBBB.
Implications:
- This case highlights the significant impact of pacing rate on LBBP QRS morphology.
- It demonstrates the influence of retrograde impulse conduction from the LBBP site on the electrocardiogram.
- Understanding these dynamics is crucial for accurate interpretation of pacing parameters and patient management.
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