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Computed Tomography‐Verified Pacing Location of Micra Leadless Pacemakers and Characteristics of Paced Electrocardiograms in Bradycardia Patients

Year: 2025

Type: article

Abstract: INTRODUCTION: The leadless pacemakers are implanted routinely under fluoroscopic image, yet the pacing sites and corresponding paced electrocardiography (ECG) remain unclear. This study was to determine the computed tomography (CT)-verified location of the leadless Micra pacemakers (Micra) and ECG characteristics. METHODS: Twenty consecutive patients who met the pacemaker indications for bradycardia and underwent fluoroscopy assisted Micra implantation were enrolled. All subjects underwent a postoperative CT scan to determine the precise location of the Micra pacing tip. Paced 12-lead ECG characteristics were analysed and correlated with the Micra tip location. RESULTS: In the nine partitions of fluoroscopic RAO images, 14 (70%) of 20 patients had the Micra tip in zone 5, 5 (25%) in zone 6 and 1 in zone 2. Reconstructed CT 3-D cardiac images found Micra tips mostly clustered near the anterior insertion between the RV septum and free wall with 12 cases at the insertion-septal side and 8 at the free-wall side. ECG morphological analysis found that the peak deflection index in ECG lead V1 was 0.409 ± 0.058 for Micra tips at the insertion-septal side and 0.527 ± 0.062 in the free-wall side (p < 0.001 between two sides) and R wave amplitude in lead V6 appeared larger for Micra tips in the free-wall group compared to Micra tips in the insertion-septal group, while there was no difference in QRS duration between two sides. CONCLUSION: In routine Micra implantation, the pacing sites were often located in the anterior insertion region.

Source: Clinical Cardiology

DOI: 10.1002/clc.70209