In a recent article published in Circulation, researchers investigated the performance of a dual-chamber leadless pacemaker system, focusing on its ability to maintain atrioventricular (AV) synchrony in patients requiring pacing. The research aims to evaluate the safety and efficacy of this innovative device, particularly in achieving optimal pacing outcomes without the complications associated with conventional lead-based systems.
Study: Atrioventricular Synchrony Delivered by a Dual-Chamber Leadless Pacemaker System. Image Credit: karegg/Shutterstock.com
Background
Atrioventricular synchrony is crucial for effective cardiac function, as it ensures that the atria and ventricles contract in a coordinated manner. Traditional pacemakers, which utilize leads to connect to the heart, have been the standard for managing patients with bradycardia and other pacing indications. However, these systems come with risks, such as lead-related complications, infections, and the need for surgical interventions.
Leadless pacemakers, which are implanted directly into the heart without leads, have emerged as a promising alternative. Previous studies have demonstrated the feasibility of single-chamber leadless pacemakers, but the dual-chamber approach offers the potential for improved AV synchrony, which is essential for patients with specific pacing needs. This study builds on existing knowledge by exploring the dual-chamber leadless pacemaker's performance in a diverse patient population.
The Current Study
This study was designed as a prospective, multicenter, single-arm clinical trial to evaluate the performance of a dual-chamber leadless pacemaker system. The trial enrolled patients from 77 centers across the United States, Canada, Europe, and the Asia-Pacific region. Eligible participants were adults with a clinical indication for dual-chamber pacing, including those with symptomatic bradycardia due to sinus node dysfunction or atrioventricular block.
Inclusion criteria required patients to be free of mechanical tricuspid valve prostheses, inferior vena cava filters, or pre-existing pacing leads. After obtaining informed consent, patients underwent implantation of the dual-chamber leadless pacemaker system, which consists of separate leadless devices for the atrium and ventricle. The implantation procedure was performed using a transvenous approach, guided by fluoroscopy, and followed standard protocols to ensure optimal device placement.
Post-implantation, patients were monitored for 90 days to assess safety and performance outcomes. At three months, 12-lead Holter electrocardiographic recordings were obtained to evaluate atrioventricular synchrony across various postures and activities, including sitting, standing, and walking. The primary endpoint was defined as the percentage of atrioventricular synchronous beats, with a standard PR interval limit of 300 milliseconds.
An independent core laboratory conducted manual adjudication of the Holter recordings to determine the percentage of synchronous beats. Additionally, the success rates of implant-to-implant (i2i) communication between the atrial and ventricular devices were assessed. Statistical analyses, including Wilcoxon signed-rank tests and ANOVA of linear mixed-effects models, were employed to evaluate the relationships between atrioventricular synchrony and various patient factors, including heart rate and activity levels.
Results and Discussion
The implantation attempts had success rates of 98.7% for dual leadless pacemaker implantation. At the three-month assessment, 424 patients completed the AV synchrony evaluation. The results indicated that 97.9% of these patients participated in at least one posture/activity assessment, with 95.9% having proper device programming.
The study recorded a total of 2,786 possible posture/activity recordings, with a small percentage (3.6%) not obtained due to incomplete participation. The primary safety and performance endpoints were met, with 90.3% of patients experiencing freedom from device-related complications within the first 90 days. Additionally, 97.3% of patients demonstrated AV synchrony in at least 70% of beats while in a sitting posture. These findings underscore the dual-chamber leadless pacemaker's effectiveness in maintaining AV synchrony, which is critical for optimal cardiac function.
The results of this study highlight the dual-chamber leadless pacemaker's potential to enhance AV synchrony in patients requiring pacing. The high rates of successful implantation and the favorable safety profile observed in the initial 90 days post-implantation are promising indicators of the device's clinical viability.
The ability to achieve AV synchrony in a significant majority of patients suggests that this technology may offer advantages over traditional pacing systems, particularly for those with specific pacing requirements. However, the study also acknowledges limitations, including the exclusion of certain patients and the relatively short duration of Holter monitoring.
Future research should aim to explore the long-term effects of this pacing technology on patient outcomes, including quality of life and symptom relief. Additionally, the impact of various factors, such as heart rate variability and activity levels, on AV synchrony warrants further investigation.
Conclusion
In conclusion, this study's findings contribute to the growing body of evidence supporting leadless pacing as a viable alternative to traditional systems. As the field of cardiac pacing continues to evolve, ongoing research will be essential to fully understand the long-term implications of this technology on patient care and outcomes.
The dual-chamber leadless pacemaker holds promise for improving the quality of life for patients with pacing needs, paving the way for future innovations in cardiac rhythm management.
Journal Reference
James E. Ip, MD, Mayer Rashtian, et al. (2024). Atrioventricular Synchrony Delivered by aDual-Chamber Leadless Pacemaker System. Circulation 150, 6, 439-450. DOI: 10.1161/CIRCULATIONAHA.124.069006, https://www.ahajournals.org/doi/epdf/10.1161/CIRCULATIONAHA.124.069006