Monocentric experience of leadless pacing with focus on challenging cases for conventional pacemaker

Leadless cardiac pacemaker has been developed to reduce complications related to cardiac pacing and is considered as an alternative to conventional pacemaker although safety and efficacy data in clinical practice are limited. The purpose of this study was to investigate the safety and efficacy profile of Micra Transcatheter Pacing System (TPS) used in daily clinical activity with a focus on challenging cases for conventional pacing.

A total of 66 patients (46 men, 79.1 ± 9.7 years) having a Class I or II indication for ventricular pacing underwent a Micra TPS implant procedure. All patients were enrolled in a prospective registry. Follow-up visits were scheduled at discharge and after 1, 3, 6 and 12 months.

Primary indication for pacing was third degree atrioventricular block (30.3%), sinus node dysfunction (21.2%) or permanent atrial fibrillation with bradycardia (45.5%). The device was successfully implanted in 65 patients (98.5%). During follow-up of 10.4 ± 6.1 months (range 1-23 months), electrical measurements remained stable. Mean pacing capture threshold, pacing impedance and R-wave sensing were respectively 0.57 ± 0.32 V, 580 ± 103 Ohms, 10.62 ± 4.36 mV at the last follow-up. One major (loss of function) and three minor adverse events occurred. Pericardial effusion, dislodgement, device related infection or pacemaker syndrome were not observed. Micra TPS implantation was straightforward for patients with congenital or acquired cardiac and/or vascular abnormalities, previous tricuspid surgery and after heart transplantation.

Our experience confirms that implantation of Micra is safe and efficient in a real world population including patients who present a challenging condition for conventional pacing.