Prospective Cohort Study of Bachmann Bundle Versus Right Atrial Appendage Pacing: Impact on Atrial Cardiomyopathy Evaluated by Echocardiographic Parameters and Clinical Outcome

Prospective Cohort Study of Bachmann Bundle Versus Right Atrial Appendage Pacing: Impact on Atrial Cardiomyopathy Evaluated by Echocardiographic Parameters and Clinical Outcome

The goal of this observational study is to evaluate the impact of different atrial pacing sites-Bachmann's bundle pacing versus right atrial appendage pacing-on the development and progression of atrial cardiomyopathy in patients diagnosed with sick sinus syndrome who are undergoing permanent pacemaker implantation.

Previous studies have reported that conventional Right Atrial Appendage pacing is associated with delayed atrial activation time. A higher burden of atrial pacing at this site has been linked to an increased incidence of atrial fibrillation and atrial tachycardia. Furthermore, structural and functional deterioration of the atria-specifically Left Atrial dilation and reduced left atrial strain-has been observed in patients with a high percentage of Right Atrial Appendage pacing. These changes are known to accelerate the progression of atrial cardiomyopathy, potentially leading to adverse long-term clinical outcomes.

To address these limitations, Bachmann Bundle Pacing has emerged as a promising alternative pacing site. The Bachmann bundle is a major atrial myoarchitecture connecting the right and left atria. Pacing at this site is expected to facilitate interatrial conduction, thereby restoring interatrial synchrony and mitigating interatrial block. Prior research indicates that pacing at the Bachmann bundle is associated with a reduced incidence of atrial fibrillation and atrial tachycardia, suggesting distinct benefits regarding atrial electrophysiological outcomes. However, existing studies have primarily focused on electrophysiological parameters, such as arrhythmia incidence. Consequently, the impact of Bachmann Bundle Pacing on atrial structural and functional remodeling remains to be clearly elucidated.

Therefore, this study is designed as a single-center cohort study enrolling a total of 200 subjects (100 prospective and 100 retrospective). The investigators will analyze echocardiographic parameters over a 12-month period following pacemaker implantation. By comprehensively analyzing imaging parameters (left atrial/right atrial strain and volume changes assessed via echocardiography) and clinical outcomes (atrial arrhythmias, heart failure hospitalization, and mortality), this study aims to investigate the differential effects of Bachmann Bundle Pacing versus Right Atrial Appendage pacing on the development and progression of atrial cardiomyopathy.

Inclusion Criteria:

• Patients aged 19 years or older
• Patients diagnosed with sick sinus syndrome who are scheduled for de novo implantation of a permanent pacemaker or permanent implantable cardioverter-defibrillator
• Patients or their legal representatives who voluntarily consent to the access of medical records and study data throughout the entire research period

Exclusion Criteria:

• Patients with persistent or permanent AF
• Patients with a life expectancy of less than one year due to other comorbidities
• Pregnant or breastfeeding women
• Patients who refuse active treatment