Association Between Micra Transcatheter Pacing System Curvature and Capture Threshold During Implantation

BACKGROUND: No previous studies have examined the relationship between Micra transcatheter pacing system (TPS) curvature and acceptable thresholds during implantation. This study aimed to evaluate the association between Micra TPS curvature and pre-deployment capture thresholds. METHODS: The Micra TPS was successfully implanted with the assistance of right ventriculography in 180 patients. The curvature of the Micra TPS prior to deployment was analyzed using archived right anterior oblique (RAO) images from the first deployment, with the aid of Origin software (OriginLab Corporation, USA), while electrical parameters were recorded from 0 to 30 min at 10-min intervals. RESULTS: Among 159 eligible patients, 126 (79.2%) demonstrated acceptable thresholds with a mean curvature of 0.58 ± 0.18. The high-threshold group (n = 33, 20.8%) exhibited significantly greater curvature (1.36 ± 0.64). Receiver operating characteristic analysis indicated that Micra TPS curvature ≤0.799 predicted acceptable thresholds with 90.9% sensitivity and 91.3% specificity (area under the curve = 0.958, 95% confidence interval: 0.924-0.992), with stable thresholds maintained in the acceptable group. No procedural complications occurred. CONCLUSIONS: A curvature of ≤0.799 in the RAO view of the Micra TPS prior to deployment reliably indicates acceptable capture thresholds. Combining curvature assessment with right ventriculography enhances the procedural safety of Micra implantation.