Electrogram transition patterns in left bundle branch pacing: a case report.

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Left bundle branch pacing (LBBP) is a promising technique for cardiac pacing.
• Confirming selective capture of the left bundle branch (LBB) using electrogram (EGM) criteria remains a challenge.

Purpose of the Study:

• To illustrate the electrophysiological features of selective LBB capture during pacing.
• To demonstrate the utility of dynamic electrogram analysis in confirming LBBP.

Main Methods:

• A case report of a 69-year-old male with complete atrioventricular block undergoing LBBP implantation.
• Real-time electrogram monitoring with specific filter settings was used.
• Stimulus-to-V6 R-wave peak time (Sti-V6 RWPT) and output reduction were analyzed dynamically.

Main Results:

• An abrupt shortening of Sti-V6 RWPT from 87 to 69 ms indicated a transition to LBBP.
• Elimination of myocardial excitation notches and isoelectric EGMs confirmed selective LBB capture.
• Further output reduction led to prolonged Sti-V6 RWPT and suggested fascicular-level conduction delay.

Conclusions:

• Dynamic EGM analysis can reveal electrophysiological features of pacing modalities, even with signal artifacts.
• Morphological patterns in EGMs aid in differentiating pacing types.
• Further validation of these electrophysiological observations is warranted.