A dual-chamber leadless pacemaker provided reliable long-term atrioventricular synchrony

1. In the prospective study, a dual-chamber leadless pacemaker system met primary safety endpoints at three-month follow-up.

2. The dual-chamber leadless pacemaker system provided atrial pacing and reliable atrioventricular synchrony for three months after implantation.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Conventional pacemakers consist of a surgically implanted pulse generator with transvenous leads. Recently, a modular dual-chamber leadless pacemaker system with bidirectional communication and a fixation mechanism enabling the placement of a right atrial leadless packer was developed. However, there remains a gap in knowledge as to understanding the safety and performance of this dual-chamber leadless pacemaker system in humans. Overall, this study found that a leadless dual-chamber pacemaker with bidirectional wireless communication met the primary safety and performance endpoints at three months in patients with standard indications for dual-chamber pacing. This study was limited by its single-group nature, which precluded direct comparison, and with only short-term follow-up data reported. Nevertheless, these study’s findings are significant, as they demonstrate that this leadless dual chamber pacemaker system provided safety and performance at three months in patients with indications for dual chamber pacing.

Click to read the study in NEJM

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In-Depth [single-group multicenter study]: This prospective, multicenter, single-group study was conducted to study the leadless pacemaker system. Patients who had a standard indication for dual-chamber pacing and an age of at least 18 years were eligible for the study. Patients who had a mechanical tricuspid valve prosthesis, inferior vena cava filter, preexisting pacing or defibrillation leads, and electrically active implantable medical devices were excluded from the study. The primary outcome measured was freedom from complications through 90 days, as well as a combination of adequate atrial capture threshold (≤3.0 V at 0.4 msec) and atrial sensing amplitude (P wave of ≥1.0 mV) at the three-month visit. Outcomes in the primary analysis were assessed via an adaptive design for sample size reestimation and a multiple imputation method based on logistic regression. Based on the primary analysis, the primary safety endpoint was met in 271 patients (90.3%; 95% Confidence Interval [CI], 87.0 to 93.7), which exceeded the performance goal of 78% (p<0.001). The first primary performance endpoint was met in 90.2% of the patients (95% CI, 86.8 to 93.6), which exceeded the performance goal of 82.5% (p<0.001). At least 70% atrioventricular synchrony was achieved in 97.3% of the patients (95% CI, 95.4 to 99.3), which exceeded the performance goal of 83% (p<0.001). In summary, the present study demonstrates that the dual-chamber leadless pacemaker met the primary safety endpoint and provided atrial pacing and reliable atrioventricular synchrony for three months after implantation.

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