J Am Heart Assoc. 2026 Sep 18:e050579. doi: 10.1161/JAHA.126.050579. Online ahead of print.
ABSTRACT
BACKGROUND: The Aveir leadless pacemaker uses an active fixation method, enabling real-time monitoring of electrical parameters during implantation. However, comprehensive studies on the electrical parameters during this procedure are rare. This study aims to analyze the electrical characteristics to further guide the implantation strategy and improve device stability and safety.
METHODS: This multicenter retrospective study enrolled 119 patients (mean age, 70.18 years; 59.58% women) who received the Aveir VR leadless pacemaker from November 2024 to May 2025 at 10 centers in China. Intraprocedural variations in commanded electrogram, current of injury (COI), impedance, pacing threshold, and sensing parameters were meticulously documented.
RESULTS: Commanded electrogram mapping demonstrated various morphologies (R, RS, QR, QRS, and QS), aiding localization. During fixation, 58.82% of patients exhibited an increased COI from mapping to 0.5 turns, which was associated with reduced short-term pacing thresholds. From 0.5 to 1 turn, 52.94% showed a further increase in COI. Receiver operating characteristic analysis revealed that an impedance increase has predictive value for short-term pacing thresholds, with an area under the receiver operating characteristic curve of 0.634 and a cutoff value of 230 Ω (sensitivity, 0.622; specificity, 0.41). Lead stability showed a moderate correlation with impedance increase (R=0.44, P<0.001), while the correlation with COI was weak.
CONCLUSIONS: During Aveir implantation, commanded electrogram variations guide site localization. Initial COI increases (0-0.5 turns) are linked to optimal short-term thresholds. Monitoring impedance increase is vital, as a threshold of 230 Ω serves as a key indicator of device stability and fixation quality.
PMID:42757909 | DOI:10.1161/JAHA.126.050579