Physiologic Differentiation Between Selective His Bundle, Nonselective His Bundle and Septal Pacing

Area of Science:

• Cardiology
• Electrophysiology
• Medical Device Technology

Background:

• Physiologic ventricular pacing aims to mimic natural heart activation.
• His bundle (HB) pacing is an emerging technique for achieving this goal.
• Electrocardiography is key to assessing pacing effectiveness and diagnosing capture types.

Purpose of the Study:

• To review and differentiate the electrocardiographic characteristics of three His bundle pacing capture types.
• To highlight the diagnostic importance of recognizing selective HB capture, nonselective HB capture, and selective right ventricular septal (RVS) capture.
• To provide guidance for interpreting pacing-induced electrocardiographic patterns.

Main Methods:

• Review of existing literature and electrocardiographic criteria for His bundle pacing.
• Analysis of electrophysiological principles governing ventricular activation during different pacing modes.
• Description of distinct electrocardiographic signatures for each capture type.

Main Results:

• Selective HB capture: Pacing activates the His-Purkinje system, leading to normal ventricular activation.
• Nonselective HB capture: Pacing activates both the HB and adjacent RVS myocardium, resulting in faster-than-usual but abnormal septal activation.
• Selective RVS capture: Pacing directly activates the RVS myocardium without engaging the HB, mimicking conventional right ventricular pacing.

Conclusions:

• Accurate differentiation of HB pacing capture types is essential for optimizing pacing strategies.
• Electrocardiographic analysis is critical for confirming successful selective HB pacing.
• Understanding these distinctions aids in achieving true physiologic ventricular pacing.