Micra trans-catheter leadless pacemaker implantation in a patient with large right heart.

The use of leadless trans-catheter pacemakers is increasing particularly in the elderly population. However, its indication for those with anatomical anomaly remains unknown. We had a 75-year-old woman with atrial standstill and ventricular escape. Micra leadless pacemaker (Medtronic, Inc, Minneapolis, MN, USA) failed to be deployed due to too enlarged right atrium accompanied by atrial septal deficiency, followed by successful implantation of transvenous pacemaker lead by using SelectSecure lead (Medtronic) with a C315 delivery catheter that enhanced back-up force toward the ventricular septum against significant tricuspid regurgitation. The Micra is a promising system, but we should understand its limitations as well as alternative systems particularly for such an anatomical anatomy. <Learning objective: A Micra leadless trans-catheter pacemaker is a promising system with less invasiveness, particularly for elderly patients, but we should understand its technical limitation and consider alternative systems if necessary, particularly for those with enlarged right heart.>.