Atrial Synchrony Evaluation of Bachmann Bundle Pacing in Sick Sinus Syndrome

Clinical Study on the Application of Two-dimensional Speckle Tracking Imaging to Evaluate the Atrial Synchrony of Bachmann Bundle Pacing in Patients With Sick Sinus Syndrome

This is a prospective, randomized study to compare the effects of Bachmann bundle pacing (BBP) versus conventional right atrial appendage (RAA) pacing on atrial electromechanical synchrony in patients with sick sinus syndrome (SSS). The study utilizes two-dimensional speckle tracking imaging (2D-STI) to assess improvements in cardiac function and synchrony, aiming to determine a more optimal pacing site for SSS patients.

Study Overview

• Status: Completed
• Conditions: Sick Sinus Syndrome
• Intervention / Treatment: Device: Bachmann Bundle Pacing; Device: Right Atrial Appendage Pacing

Detailed Description

Sick sinus syndrome (SSS) is a common indication for permanent pacemaker implantation. Conventional right atrial appendage (RAA) pacing, however, is non-physiological and may lead to atrial conduction delays, atrial remodeling, and an increased risk of atrial fibrillation. Bachmann bundle pacing (BBP) is emerging as a more physiological pacing strategy that may correct atrial conduction delays and improve electromechanical synchronization. This study prospectively enrolled and randomized 72 patients with SSS to receive either BBP or RAA pacing. The primary objective is to evaluate the differences in atrial synchrony, cardiac function, and pacing parameters between the two groups at baseline, 1-month, and 3-month follow-ups, using electrocardiography and two-dimensional speckle tracking imaging (2D-STI). The study aims to provide evidence for BBP as a superior treatment option for improving long-term outcomes in SSS patients.

• Study Type: Interventional
• Enrollment (Actual): 72
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Hubei
    • Shiyan, Hubei, China, 442000
      • Beijing Anzhen Hospital, Capital Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Meets diagnostic criteria for sick sinus syndrome (e.g., persistent sinus bradycardia <50 bpm, sinus arrest, sinoatrial block, or tachy-brady syndrome).
• Age between 30 and 90 years.
• Has not taken any other antiarrhythmic drugs within one month prior to enrollment.
• Has not participated in any other related clinical trials.
• Voluntarily signs the informed consent form.

Exclusion Criteria:

• Patients with severe primary diseases causing unstable vital signs (e.g., severe circulatory, digestive, or neurological system diseases).
• Patients with a history of recurrent syncope, Adams-Stokes syndrome, severe bradycardia (lowest sinus rhythm <30 bpm), or long RR interval >3s.
• Pregnant or lactating women.
• Patients with mental illness.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Bachmann Bundle Pacing (BBP) Group; Patients were randomized to receive a permanent pacemaker with the atrial lead placed in the Bachmann bundle region. They were followed up at 1 month and 3 months post-procedure.	Device: Bachmann Bundle Pacing; Implantation of a permanent pacemaker system. The atrial lead (Medtronic 3830 active electrode) is surgically positioned and fixed in the Bachmann bundle region, located at the angle between the superior vena cava and the atrium in the mid-posterior position of the high atrial septum. Successful placement is confirmed by achieving a P-wave width shortening of at least 30ms compared to the preoperative P-wave. The ventricular lead is positioned in the mid-to-lower portion of the ventricular septum. Pacing parameters are measured and confirmed to be good.
Active Comparator: Right Atrial Appendage (RAA) Pacing Group; Patients were randomized to receive a permanent pacemaker with the atrial lead placed in the conventional right atrial appendage. They were followed up at 1 month and 3 months post-procedure.	Device: Right Atrial Appendage Pacing; Implantation of a permanent pacemaker system using the conventional technique. The atrial active electrode is surgically positioned and fixed in the right atrial appendage. The ventricular lead is placed in the mid-to-lower portion of the ventricular septum. Pacing parameters (sensing > 2.0mV; impedance between 300 to 1000Ω; threshold < 1.5mV) are confirmed to be good.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Inter-atrial Electromechanical Delay (Inter AEMD)	Measured by two-dimensional speckle tracking imaging (2D-STI) as the time difference between the onset of the P-wave on the electrocardiogram (ECG) and the peak longitudinal strain of the lateral walls of the right and left atria. A smaller value indicates better inter-atrial synchrony.	Baseline, 1 Month Post-procedure, 3 Months Post-procedure
Change in Intra-atrial Mechanical Delay (IAMD)	Measured by 2D-STI as the standard deviation of the time-to-peak longitudinal strain of six segments of the left atrium. A smaller value indicates better intra-atrial synchrony.	Baseline, 1 Month Post-procedure, 3 Months Post-procedure
Change in Intra-right Atrial Electromechanical Delay (Intra-right AEMD)	Measured by 2D-STI as the time difference between the earliest and latest peak longitudinal strain within the right atrium segments.	Baseline, 1 Month Post-procedure, 3 Months Post-procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in P-wave Duration (PWD) and Morphology	Measured from the 12-lead surface ECG, including P-wave duration (P-AT, P-Am) and P-wave axis (P-aI, P-aL).	Baseline, 1 Month Post-procedure, 3 Months Post-procedure
Change in QRS Duration and Axis	Measured from the 12-lead surface ECG.	Baseline, 1 Month Post-procedure, 3 Months Post-procedure
Change in Left Atrial (LA) and Right Atrial (RA) Dimensions	Measured by standard 2D echocardiography.	Baseline, 1 Month Post-procedure, 3 Months Post-procedure
Change in Left Ventricular End-Systolic Diameter (LVESD) and End-Diastolic Diameter (LVEDD)	Measured by standard 2D echocardiography.	Baseline, 1 Month Post-procedure, 3 Months Post-procedure
Change in Left Atrial Strain Parameters	Includes left atrial reservoir strain (LASr), conduit strain (LAScd), and contraction strain (LASct), measured by 2D-STI.	Baseline, 1 Month Post-procedure, 3 Months Post-procedure
Recurrence of Atrial Arrhythmia	Number of patients experiencing newly developed or recurrent atrial fibrillation or atrial tachycardia.	Up to 1 year
Change in Atrial Pacing Threshold	Measured via pacemaker programmer interrogation. Unit: millivolts (mV).	1 Month Post-procedure, 3 Months Post-procedure
Change in Atrial Sensing (P-wave amplitude)	Measured via pacemaker programmer interrogation. Unit: millivolts (mV).	1 Month Post-procedure, 3 Months Post-procedure
Change in Atrial Pacing Impedance	Measured via pacemaker programmer interrogation. Unit: Ohms (Ω).	1 Month Post-procedure, 3 Months Post-procedure
Change in Ventricular Pacing Threshold	Measured via pacemaker programmer interrogation. Unit: millivolts (mV).	1 Month Post-procedure, 3 Months Post-procedure
Change in Ventricular Sensing (R-wave amplitude)	Measured via pacemaker programmer interrogation. Unit: millivolts (mV).	1 Month Post-procedure, 3 Months Post-procedure
Change in Ventricular Pacing Impedance	Measured via pacemaker programmer interrogation. Unit: Ohms (Ω).	1 Month Post-procedure, 3 Months Post-procedure
Percentage of Ventricular Pacing	Measured via pacemaker programmer interrogation. Unit: Percentage (%).	1 Month Post-procedure, 3 Months Post-procedure

Collaborators and Investigators

• Sponsor: Shiyan City Renmin Hospital
• Investigators: Principal Investigator: Yongquan Wu, Beijing Anzhen Hospital

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2023
• Primary Completion (Actual): April 30, 2024
• Study Completion (Actual): January 31, 2025

Study Registration Dates

• First Submitted: June 26, 2025
• First Submitted That Met QC Criteria: July 3, 2025
• First Posted (Estimated): July 8, 2025

Study Record Updates

• Last Update Posted (Estimated): July 8, 2025
• Last Update Submitted That Met QC Criteria: July 3, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiac Conduction System Disease; Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Disease; Arrhythmias, Cardiac; Heart Block; Arrhythmia, Sinus; Syndrome; Sick Sinus Syndrome
• Other Study ID Numbers: 2025126x

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No