Accidental reactivation of a retained pacemaker leading to competitive ventricular pacing between two pacemakers: A case report

Herein, we report a rare clinical case of competitive ventricular pacing caused by the accidental reactivation of a retained pacemaker two years after device replacement. Initially, two years following the implantation of the new pacemaker, the device demonstrated typical dual-chamber pacing. However, recent follow-up electrocardiography revealed two distinct QRS morphologies. Holter monitoring, imaging studies, and a review of prior procedural records confirmed that this phenomenon was caused by the unexpected reactivation of the retained pacemaker, leading to competitive ventricular pacing. A detailed analysis of the underlying causes of inadvertent reactivation led to the implementation of targeted interventions, which successfully resolved the issue of competitive ventricular pacing induced by dual pacemakers.