Miniaturized Transcatheter Leadless Pacemaker in a Patient with Double Mechanical Prosthesis

Case Report A 75-year-old female patient with a background of systemic arterial hypertension, chronic atrial fibrillation with an episode of peripheral arterial embolism in the right upper limb and rheumatic valve disease, underwent mitral and aortic valve replacement receiving two mechanical valve prosthesis in combination with left atrial appendage occlusion. Six months after surgery, pharmacologic therapy to achieve heart rate control was very difficult and inadequate and the patient was scheduled for permanent pacemaker implantation. In order to avoid lead or pocket complications, the Micra transcatheter leadless pacemaker (Medtronic Inc., Minneapolis, MN, USA) was implanted through the femoral vein using a steerable catheter delivery system with the use of a 23-French introducer. The procedure was performed under uninterrupted acenocoumarol therapy with therapeutic international normalized ratio (INR 2.5). Sedation and local anesthesia was applied and the implant was successful upon initial device positioning at the mid-septum of the right ventricle with no complications. Access site closure was performed using a subcutaneous venous figure-of-8 suture. The pacing capture threshold at implant was 0.38 V measured at 0.24 ms, the R-wave sensing amplitude was 8.8, and the pacing impedance was 730 ohms. There were no complications and the patient was discharged home the next day after chest X-ray showed the device was positioned perfectly (Figure1) and electrical pacing parameters were appropriate. At three months of followup the patient has shown no complications and the pacing capture threshold was 0.38 V at 0.24 ms, the R-wave sensing amplitude was 9.2 and the pacing impedance was 680 ohms.