Right Ventricular Implantation of an Aveir™ AR Device for Bradycardia in a 90-Year-Old Woman with Atrial Fibrillation and Small Right Ventricular Dimensions.

We report a case of implanting an Aveir™ AR (atrial) leadless pacemaker (Abbott, Chicago, IL, USA) in the right ventricle (RV) of a 90-year-old woman with permanent atrial fibrillation with pauses. The patient initially received an Aveir™ VR (ventricular) device for rate support. During implantation, elevated pacing thresholds and tricuspid valve (TV) interaction were noted, which improved with repositioning. The patient subsequently presented with recurrent loss of capture secondary to elevated thresholds. Device interrogation and imaging suggested that the Aveir™ VR device was suboptimal due to the patient's small RV cavity and interaction with TV. To address this, the pacemaker was extracted, and an Aveir™ AR device-featuring a smaller profile-was successfully implanted in the RV, achieving stable fixation. To the best of our knowledge, this is the first reported case of off-label RV implantation of an Aveir™ AR device. This case illustrates the versatility of modular leadless pacing systems and underscores the importance of tailoring device selection to individual cardiac anatomy, particularly TV, in elderly patients with small RV dimensions.