Study of the optimum fluoroscopic angle for the implant fixation test of a leadless cardiac pacemaker

The Micra TPS™ (Medtronic) is the first leadless pacemaker listed in China. The best fluoroscopic angle for the intraoperative fixation test is selected according to different implantation sites to reduce the fluoroscopy duration and radiation dose, and the test is based on the early safety and effectiveness of the device after implantation. A total of 110 patients who underwent Micra TPS™ implantation were selected. Eighty patients were in group A, and 30 patients were in group B. Under the guidance of the conclusions from group A, the fluoroscopy duration, radiation dose and number of fluoroscopic positions of the best fluoroscopic angle of the fixation test according to different positions of the implanted interventricular septum were compared. In 85.0% of the group A implants, these angles were based on the right interior oblique (RAO) angle, with 48.5% cranial (CRA) and 29.4% caudal (CAU) angles. The angle of the tilting head side of the RAO angle was prioritized in group B, and referring to the average angle data, the average fluoroscopy duration for finding the best angle of fixation test was 1.7 ± 0.6 vs. 3.2 ± 1.8 min (P < 0.001), the average radiation dose was 270.4 ± 56.3 vs. 338.1 ± 112.9 mGy (P = 0.002), and the average number of fluoroscopic positions was 2.2 ± 0.6 vs. 4.2 ± 2.1 (P < 0.001), which was significantly less than that in group A. This study found that there was regularity in the fluoroscopic angle for the fixation test during Micra TPS™ operation.