LAUSR

Received 5 September 2016; revision accepted for publication 20 September 2016. A 82-year-old woman with moderately severe valvular (tricuspid and mitral) disease and chronic atrial fibrillation associated with severe bradycardia underwent implantation of a leadless cardiac pacemaker MicraTM(Transcatheter Pacing System (TPS), Model MC1VR01, Medtronic Inc., Minneapolis, MN, USA). The implantation was the fifth scheduled TPS implantation in our centre, all by one single operator (CG). After five redeployments, the TPS was launched at an infero-basal position (pacing threshold of 1.0 V at 0.25 ms, pacing impedance at 510 Ohm and sensing: 11.2 ms) (panel A). Before discharge, the electrical parameters were unchanged. However, 10 days after the implantation, an isolated increase of the pacing threshold (2.50 V at 0.24 ms) was observed that prompted closer follow-up. Three weeks later, the patient was readmitted for pre-syncope and heart failure. ECG showed intermittent ventricular non-capture. Control of the TPS confirmed a high pacing threshold (> 5.00 V at 0.24 ms) with stable pacing impedance and ventricular sensing. Transoesophageal echocardiography showed worsening of the mitral valvular disease and known moderately Successful repositioning of leadless cardiac pacemaker during open heart surgery