An unwanted left bundle branch block: The proteus-unveiling of his bundle pacing

His bundle pacing (HBP) has emerged in the last decade as an attractive alternative to conventional right ventricular pacing (RVP), being the most physiologic form of cardiac stimulation by the avoidance of pacing-induced intraventricular and interventricular dyssynchrony.1 Although the premises to replace customary RVP are sound, evidence is still limited, with only small, randomized trials available. Furthermore, HBP threshold increase leading to unpredictable His capture at follow-up or to excessive battery drain are a concern in young patients, especially when pacemaker dependent.