Pacing Performance of a Modular Communicative Leadless Pacing-Defibrillator System

MODULAR ATP is an ongoing trial assessing the efficacy of a subcutaneous implantable cardioverter defibrillator (S-ICD) in communication with a leadless pacemaker (LP) that can deliver bradycardia pacing and antitachycardia pacing. The objective of this study was to assess safety and pacing performance of the investigational LP.

The study enrolled patients with an ICD indication and at high risk for monomorphic ventricular tachycardia. Pacemaker dependent patients were excluded. Primary safety endpoint 2 was the percentage of patients free from major LP-related complications at 12 months. The secondary effectiveness endpoint assessed the rate response performance of the LP under workload. Parameters related to the pacing performance were also measured.

In 297 patients, the mean age was 59±12 years, the mean left ventricular ejection fraction was 35.3±13.1%, and 17.5% were female. LP implant was attempted in 286 patients and was successful in 100%. The major LP-related complication free rate at 12 months was 97.2% (one-sided 97.5% LCL 94.5%), surpassing the performance goal of 81%. There were no LP-related complications following Implant. For the secondary effectiveness endpoint, the slope of the normalized sensor rate versus the normalized workload was 0.96 (95% LCL 0.91, 95% UCL 1.02), within the performance goal range of 0.65-1.35. At 12 months, 96.8% of patients had a pacing capture threshold ≤ 2V @ 0.4ms pulse width.

The performance of the modular pacing-defibrillator system at one year demonstrated a low complication rate and reliable pacing functionality.