Comparing two atrial pacemaker lead positions, Bachmann's bundle versus the right atrial appendage, and their effects on electrical conduction between the heart's upper chambers and on heart pressures and blood flow (haemodynamics), in adults receiving a pacemaker for sinus node dysfunction (a slow or unreliable natural heartbeat).

The effect of Bachmann's bundle pacing compared with right atrial appendage pacing on interatrial conduction delay, invasive haemodynamics and atrial strain in adults with sinus node dysfunction requiring permanent dual-chamber pacing: a prospective non-randomised cohort pilot study.

Status

Recruiting

Phases

Unknown

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12626000923369

Enrollment

Registered

2026-07-28

Start date

2026-04-30

Completion date

2027-01-30

Last updated

2026-08-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

Pacemakers for a slow or unreliable heartbeat (sinus node dysfunction) usually have the top wire placed in the right atrial appendage, but this may not be the most natural place for the heart's electrical signal to start. This study compares that standard position with pacing at Bachmann's bundle, the heart's natural electrical bridge between the two upper chambers, in adults who already need a dual-chamber pacemaker. We will measure how quickly the electrical signal travels between the upper chambers (the main measure), and also look at heart pressures and blood flow measured during the implant, left atrial function on ultrasound, the amount of atrial fibrillation recorded by the pacemaker, symptoms and quality of life, over 12 months. We expect Bachmann's bundle pacing to shorten the delay between the chambers, improve heart pressures and flow, and reduce atrial fibrillation compared with the standard position. Because the pacing site is chosen as part of normal clinical care and the study adds only measurements, this is an observational pilot designed to gather the preliminary data needed to plan a larger randomised trial.

Interventions

Description of the intervention: Bachmann's bundle pacing group. The atrial lead (Medtronic 3830) is actively fixed at the Bachmann's bundle region (SVC-RA junction) using the Lustgarten technique, as standard care. During implantation, a temporary dual-atrial configuration is created by transiently positioning the right ventricular lead in the right atrial appendage for approximately 10 minutes, with correct and precise positioning confirmed on fluoroscopy. While in this configuration the participant undergoes two study-specific measurements: focused intraprocedural transthoracic echocardiography (apical 4-chamber, 2-chamber and RV-focused views for strain and interatrial delay), and right heart catheterisation via the existing central venous access. The Swan-Ganz catheter is advanced into the right atrium, right ventricle and pulmonary artery; pulmonary capillary wedge pressure is obtained, and cardiac output is measured by triplicate thermodilution. The right ventricular lead is then repositioned to the right ventricle to complete standard dual-chamber implantation. The pacing approach is determined clinically by the treating operator and technique rather than allocated by the study; participants are grouped according to the technique they receive as standard care. Schedule and duration: a single index implantation procedure, followed by scheduled study visits at 6 and 12 months. Follow-up visits comprise pacemaker interrogation with measurement of interatrial conduction delay, targeted transthoracic echocardiography for left atrial strain and diastolic function, device-counter atrial fibrillation burden and atrial tachyarrhythmia detection, NYHA class, and the AFEQT questionnaire. Follow-up is 12 months per participant.

Study design

Allocation

Non-randomised trial

Primary purpose

Diagnosis

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

Adults with sinus node dysfunction requiring a permanent pacemaker with an atrial lead. Sinus node dysfunction is defined by documented sinus pauses (sinus arrest or sinoatrial exit block), tachy-brady syndrome, or chronotropic incompetence. Participants must be aged 18 years or older and able to give written informed consent.

Exclusion criteria

History of permanent atrial fibrillation; atrioventricular block in the absence of sinus node dysfunction; planned atrioventricular nodal ablation; spontaneous resting sinus rate above 85 bpm; pregnancy; anticipated life expectancy under one year.

Outcome results