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A Dual-Chamber Leadless Pacemaker Study
Quick Takes
- A leadless dual-chamber pacemaker with bidirectional wireless communication met the primary safety and performance endpoints at 3 months in patients with indications for dual-chamber pacing.
- Eliminating transvenous leads and the generator pocket reduces the long-term risk of infection and lead malfunction that may affect one in six patients during 3 years of follow-up.
- Given the small sample size, lack of a control group, and short follow-up, additional prospective randomized controlled studies are indicated to assess long-term safety and efficacy of dual-chamber leadless pacemaker systems.
Study Questions:
What is the safety and performance of a modular dual-chamber leadless pacemaker system with bidirectional communication and a fixation mechanism enabling placement of a right atrial leadless pacemaker system in humans?
Methods:
The Aveir DR i2i study investigators conducted a prospective, multicenter, single-group study to evaluate the safety and performance of a dual-chamber leadless pacemaker system. Patients with a conventional indication for dual-chamber pacing were eligible for participation. The primary safety endpoint was freedom from complications (i.e., device- or procedure-related serious adverse events) at 90 days. The first primary performance endpoint was a combination of adequate atrial capture threshold and sensing amplitude at 3 months. The second primary performance endpoint was ≥70% atrioventricular synchrony at 3 months while the patient was sitting. For the primary safety endpoint, the p value was calculated with the use of the one-sided z-test and an alpha level of 0.025.
Results:
Among the 300 patients enrolled, 190 (63.3%) had sinus-node dysfunction and 100 (33.3%) had atrioventricular block as the primary pacing indication. The implantation procedure was successful (i.e., two functioning leadless pacemakers were implanted and had established implant-to-implant communication) in 295 patients (98.3%). A total of 35 device- or procedure-related serious adverse events occurred in 29 patients. The primary safety endpoint was met in 271 patients (90.3%; 95% confidence interval [CI], 87.0-93.7), 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, 86.8-93.6), which exceeded the performance goal of 82.5% (p < 0.001). The mean (±SD) atrial capture threshold was 0.82 ± 0.70 V, and the mean P-wave amplitude was 3.58 ± 1.88 mV. Of the 21 patients (7%) with a P-wave amplitude of <1.0 mV, none required device revision for inadequate sensing. At least 70% atrioventricular synchrony was achieved in 97.3% of the patients (95% CI, 95.4-99.3), which exceeded the performance goal of 83% (p < 0.001).
Conclusions:
The authors report that the dual-chamber leadless pacemaker system met the primary safety endpoint and provided atrial pacing and reliable atrioventricular synchrony for 3 months after implantation.
Perspective:
This multicenter, single-group study reports that a leadless dual-chamber pacemaker with bidirectional wireless communication met the primary safety and performance endpoints at 3 months in patients with indications for dual-chamber pacing. However, the study is limited by its single-group nature, which precluded a direct comparison of its safety and performance with those of conventional transvenous pacemaker. Of note, eliminating transvenous leads and the generator pocket reduces the long-term risk of infection and lead malfunction that may affect one in six patients during 3 years of follow-up. Given the small sample size, lack of a control group, and short follow-up, additional prospective randomized controlled studies are indicated to assess long-term safety and efficacy of dual-chamber leadless pacemaker systems.
Clinical Topics: Arrhythmias and Clinical EP, Prevention, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias
Keywords: Arrhythmias, Cardiac, Atrioventricular Block, Cardiac Pacing, Artificial, Pacemaker, Artificial, Quality Improvement, Risk, Secondary Prevention
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