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NCT Number: NCT07055035

Atrial Synchrony Evaluation of Bachmann Bundle Pacing in 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.

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Key information

Conditions

Sick Sinus Syndrome Arrhythmia, Sinus Arrhythmias, Cardiac Cardiac Conduction System Disease Cardiovascular Diseases Heart Block Heart Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms

Age range

30 year–90 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Beijing Anzhen Hospital, Capital Medical University

Shiyan, Hubei, 442000, China

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Bachmann Bundle Pacing

Device

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.

Right Atrial Appendage Pacing

Device

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.

Primary outcomes

  1. Change in Inter-atrial Electromechanical Delay (Inter AEMD)

    Time frame: Baseline, 1 Month Post-procedure, 3 Months Post-procedure

    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.

  2. Change in Intra-atrial Mechanical Delay (IAMD)

    Time frame: Baseline, 1 Month Post-procedure, 3 Months Post-procedure

    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.

  3. Change in Intra-right Atrial Electromechanical Delay (Intra-right AEMD)

    Time frame: Baseline, 1 Month Post-procedure, 3 Months Post-procedure

    Measured by 2D-STI as the time difference between the earliest and latest peak longitudinal strain within the right atrium segments.

Secondary outcomes

  1. Change in P-wave Duration (PWD) and Morphology

    Time frame: Baseline, 1 Month Post-procedure, 3 Months Post-procedure

    Measured from the 12-lead surface ECG, including P-wave duration (P-AT, P-Am) and P-wave axis (P-aI, P-aL).

  2. Change in QRS Duration and Axis

    Time frame: Baseline, 1 Month Post-procedure, 3 Months Post-procedure

    Measured from the 12-lead surface ECG.

  3. Change in Left Atrial (LA) and Right Atrial (RA) Dimensions

    Time frame: Baseline, 1 Month Post-procedure, 3 Months Post-procedure

    Measured by standard 2D echocardiography.

  4. Change in Left Ventricular End-Systolic Diameter (LVESD) and End-Diastolic Diameter (LVEDD)

    Time frame: Baseline, 1 Month Post-procedure, 3 Months Post-procedure

    Measured by standard 2D echocardiography.

  5. Change in Left Atrial Strain Parameters

    Time frame: Baseline, 1 Month Post-procedure, 3 Months Post-procedure

    Includes left atrial reservoir strain (LASr), conduit strain (LAScd), and contraction strain (LASct), measured by 2D-STI.

  6. Recurrence of Atrial Arrhythmia

    Time frame: Up to 1 year

    Number of patients experiencing newly developed or recurrent atrial fibrillation or atrial tachycardia.

  7. Change in Atrial Pacing Threshold

    Time frame: 1 Month Post-procedure, 3 Months Post-procedure

    Measured via pacemaker programmer interrogation. Unit: millivolts (mV).

  8. Change in Atrial Sensing (P-wave amplitude)

    Time frame: 1 Month Post-procedure, 3 Months Post-procedure

    Measured via pacemaker programmer interrogation. Unit: millivolts (mV).

  9. Change in Atrial Pacing Impedance

    Time frame: 1 Month Post-procedure, 3 Months Post-procedure

    Measured via pacemaker programmer interrogation. Unit: Ohms (Ω).

  10. Change in Ventricular Pacing Threshold

    Time frame: 1 Month Post-procedure, 3 Months Post-procedure

    Measured via pacemaker programmer interrogation. Unit: millivolts (mV).

  11. Change in Ventricular Sensing (R-wave amplitude)

    Time frame: 1 Month Post-procedure, 3 Months Post-procedure

    Measured via pacemaker programmer interrogation. Unit: millivolts (mV).

  12. Change in Ventricular Pacing Impedance

    Time frame: 1 Month Post-procedure, 3 Months Post-procedure

    Measured via pacemaker programmer interrogation. Unit: Ohms (Ω).

  13. Percentage of Ventricular Pacing

    Time frame: 1 Month Post-procedure, 3 Months Post-procedure

    Measured via pacemaker programmer interrogation. Unit: Percentage (%).

Sponsors and collaborators

Lead sponsor

Shiyan City Renmin Hospital

Other Gov

Registry information

Official study title

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

Important dates

Study start
2023
Primary completion
2024
Study completion
2025
First posted
Jul 8, 2025
Registry last updated
Jul 8, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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