Spontaneous template beats: A physiological clue for effective left bundle area pacing.

Recent evidence suggests that left bundle area pacing (LBAP) is non-inferior to conventional cardiac resynchronization therapy (CRT) using biventricular pacing (BVP). In addition, LBAP directly recruits the native conduction system, thereby addressing several procedural limitations inherent to BVP. Despite these advantages, electrocardiographic (ECG) analysis rarely provides specific clues to identify patients who may benefit most from LBAP. We report a case in which a spontaneous "template beat" or "left bundle capture beat" was observed on the baseline ECG and propose this finding as a potential novel marker for identifying patients likely to respond favourably to this therapy.