Impact of Leadless Pacemaker Implantation Position on Subclinical Right Ventricular Perforation

INTRODUCTION: Leadless pacemakers are typically implanted in the mid-septum of the right ventricle (RV) to mitigate the risk of perforation. However, reports on the precise location of these implants are limited. This study aimed to elucidate tine-based leadless pacemaker position and presence of subclinical RV perforation through computed tomography (CT) imaging, along with the associated prognosis. METHODS: Patients who underwent heart, chest or abdomen CT after leadless pacemaker implantation were consecutively included. Two cardiologists and one radiologist reviewed the CT images to assess the position of tines and to detect RV perforation. The implantation position was categorized as the septum, RV free wall, junction of septum and RV free wall, moderator band, and RV apex. Subclinical perforation was defined as the tines of a leadless pacemaker beyond the outer myocardial contour without symptoms, pericardial effusion, hemodynamic instability, or pacemaker malfunction. RESULTS: A total of 88 patients (age, 72.9 ± 12.1 years; 42 males) were included. The interval between procedure and CT scanning was 8.6 ± 9.2 months. In 68 patients (77.3%), the leadless pacemaker was implanted at the junction of the septum and the RV free wall. Subclinical RV perforation occurred in 15 patients (17.0%). Among patients with RV perforation, the most common implantation site was the junction of the septum and the RV free wall. None of the patients with RV perforation experienced any adverse events for 12.4 ± 12.3 months. CONCLUSIONS: The most common leadless pacemaker implantation site is the junction of the septum and the RV free wall. Subclinical RV perforation is not uncommon and not associated with overt adverse outcomes.