Abstract
Leadless pacing systems have evolved toward modular configurations that enable staged restoration of atrioventricular (AV) synchrony without transvenous leads. Real-world experience with a sequential upgrade from AVEIR VR to a dual-chamber AVEIR DR system remains limited. We report a case of staged modular leadless upgrade performed in a patient with progressive sinus node dysfunction, intermittent high-grade AV block, and symptomatic loss of AV synchrony following prior ventricular leadless pacing. A 74-year-old man with a history of mitral valve repair and atrial flutter ablation initially received an AVEIR VR ventricular device. One year later, he developed sinus pauses and hemodynamic symptoms related to AV dyssynchrony. Because the patient declined transvenous pacing, an atrial AVEIR AR module was implanted to establish dual-chamber pacing within a fully leadless system. The procedure was uncomplicated and resulted in restoration of AV synchrony and clinical improvement at follow-up. This report demonstrates the feasibility of staged modular upgrades within a leadless pacing platform in selected patients with evolving conduction disease.