Pseudo-pacemaker syndrome triggered by atrioventricular hysteresis algorithm activation in a patient with left bundle branch area pacing: a case report.

Atrioventricular (AV) hysteresis algorithms are designed to minimize unnecessary ventricular pacing. This case report describes a young patient with left bundle branch area pacing (LBBAP) in whom activation of an AV-hysteresis algorithm resulted in excessive prolongation of AV intervals, leading to ineffective AV synchrony and recurrence of symptoms consistent with a pseudo-pacemaker syndrome despite permanent pacemaker implantation, including dizziness and near-syncope. The case highlights the importance of careful device programming, particularly in patients undergoing conduction system pacing.