Bachmann’s Bundle Pacing: A New Approach for Decreasing Atrial Fibrillation Incidence?

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EP LAB DIGEST. 2026;26(1):10-12.

Linda Moulton, RN, MS
Faculty: Order and Disorder EP Training Program, Critical Care ED/CCE Consulting, Calistoga, California

In the field of cardiac pacing, the concept has evolved that pacemaker leads positioned to pace portions of the cardiac conduction system provide greater benefit than leads placed in other cardiac tissue areas, representing a shift toward a physiologic pacing approach. Recently, considerable attention has been directed toward lead placement within the ventricular conduction system.^1,2 Pacing a portion of the cardiac conduction system to normalize electrical flow through the heart helps prevent conduction delay, which can lead to new arrhythmias. Attention has now turned to the right atrium (RA), with interest in using Bachmann’s bundle (BB) for atrial pacing. This paper will review the role of right atrial appendage (RAA) pacing and its consequences, and the emerging evidence for a change to BB pacing in the atria.

Background
BB is one of the accessory conducting pathways and plays a major role in interatrial conduction, preferentially conducting from the RA to the left atrium (LA). It is a

circumferential muscle bundle located at the anterior wall of the LA. BB is a direct continuation of the terminal crest (crista terminalis), which separates the systemic venous sinus of the RA from the RAA. It extends into fibers within the anterior and posterior LA, anteriorly toward the LA appendage and posteriorly toward the pulmonary veins. The tissue type is similar to that of the atrioventricular node and His-Purkinje system, but without insulating tissue being present^3-5 (Figure 1).

Van der Does et al⁶ examined conduction disturbances and unipolar voltage changes in BB associated with aging in subjects aged 36 to 83 years. They observed age-related increases in conduction abnormalities, generalized conduction slowing, and the presence of low-voltage areas. Lateral uncoupling at BB appeared to increase with advancing age, leading to P-wave prolongation and a higher likelihood of development of atrial fibrillation (AF). In a 2003 study, a 30-month follow-up of 16 patients with interatrial conduction block showed that 8 developed AF.⁷

RAA pacemaker lead placement has been performed for 50 years. This was historically favored because it was considered easier to accomplish procedurally,⁸ although it carries a risk of atrial perforation. However, the lateral location of the RAA can result in atrial conduction delays and P-wave prolongation. This activation delay has been associated with an increased risk of AF and atrial electromechanical dysfunction.^7,9

As early as 2000, the RAA pacing site was being challenged. In a study from Yu et al10 that year, pacing at various RA sites demonstrated that RAA pacing produced the longest P wave. In 2001, Bailin et al¹¹ reported a multicenter, prospective, randomized study comparing BB pacing with RAA pacing in patients with recurrent paroxysmal AF. Patients with BB pacing demonstrated shorter P-wave durations and a higher (P<0.05) rate of survival free from chronic AF at 1 year (75% vs 47% for RAA pacing). The BB area was identified without intracardiac recordings or echocardiographic guidance. The targeted lead placement site was a segment of the septum at the junction of the anterior septum and atrial roof, with the BB pacing location defined fluoroscopically.

Also in 2001, Roithinger et al¹² studied 28 patients after radiofrequency ablation for supraventricular arrhythmias. Pacing was performed using standard multipolar catheters from the presumed insertion site of BB, the coronary sinus os, the high lateral RA, and the RAA. Total atrial activation time was significantly shorter with BB pacing compared with the other sites, suggesting the potential for AF prevention. In 2002, Gozolits et al¹³ used a 65-lead electrocardiogram (ECG) to pace 15 patients from the high RA, CS os, distal CS, high RA septum, and dual sites. Endocardial atrial activation time and P-wave duration were measured, with the shortest P-wave duration observed at the high septal (BB) area. The authors concluded that BB pacing may be beneficial in patients with AF.

In 2022, Infield et al14 reported a retrospective study comparing BB pacing versus RA septal pacing. The 2 lead positions were defined by fluoroscopic lead position and P-wave criteria. BB pacing was associated with a decrease in atrial arrhythmia burden, recurrence, and new incidence. The authors suggested the need for a prospective, randomized study. In 2024, Yoshimoto et al¹⁵ compared interatrial conduction delay during BB pacing and RAA pacing using biatrial strain rate echocardiography. BB pacing was defined by ECG criteria plus P-wave duration shortening. Mechanical synchronization between the RA and LA observed with BB pacing was comparable to that seen in sinus rhythm. 

However, it may be that a single pacing site does not suit all patients. Van Schie et al¹⁶ investigated the optimal RA pacing site and suggested that it may vary among patients, indicating that the ideal site should be individually selected.

New Lead Placement Strategies
The goal in identifying a new location for atrial lead placement is to reduce the window of vulnerability during which an ectopic beat may initiate AF. Two major concerns regarding BB pacing are procedural technique and verification of location. In a 2002 animal study, investigators suggested that the optimal pacing site was the middle BB.¹⁷ This was followed in 2005 by Bailin’s early description of the technique for atrial lead implantation in BB.¹⁸ More recently, Lustgarten et al¹⁹ published a detailed step-by-step description of the BB lead implant/placement technique and, in 2025, proposed that the optimal pacing site is at the inferoseptal SVC at the RA junction.²⁰ 

Verification of the BB location during implantation has been achieved through various methods. Early studies defined BB pacing fluoroscopically.¹¹ In 2008, Saremi et al4 reported that BB and its vascular supply could be identified on cardiac computed tomography, but were less easily seen in patients with severe coronary artery disease or abnormal ECG findings. A 2022 case series used fluoroscopic and electrical mapping to identify the endocardial electrogram signature of the BB region and associated BB potentials.²¹ P-wave axis and morphology, along with the local electrogram signal at or near BB, were also used for localization. In 2025, investigators

evaluated electrogram-guided BB pacing using sheath-assisted, stylet-driven atrial lead implantation.²² They incorporated 12-lead P-wave morphology and electrogram analysis, recorded BB potentials in most patients, and performed threshold testing that demonstrated BB capture in >80%. (Figure 2)

Several authors have reported consistent observations regarding P-wave morphology that characterize BB pacing (capture criteria)^11,14,21,23 These include: a P-

wave vector similar to that seen in normal sinus rhythm, with an upright P wave in leads I, II, III, and aVF; a biphasic or negative P wave in V1; a peaked and symmetric P wave in the inferior limb leads, with paced P-wave amplitude typically greater than that of the sinus P wave; and a shorter P-wave duration compared with sinus rhythm, usually >10 ms when baseline interatrial conduction delay is present. (Table, Figure 3)

Extending this concept further, 2 recent case reports described the implantation of a wireless atrial pacemaker within BB.^24,25 

In addition to reducing the incidence of AF, BB pacing may also provide benefits for patients with heart failure. Subramanian et al²³ examined the effects of BB pacing in patients with nonobstructive hypertrophic cardiomyopathy and heart failure with preserved ejection fraction plus interatrial delay on ECG; they found that BB pacing resulted in improved NT-proBNP levels, exercise capacity, and diastolic function. In another study, Saga et al²⁶ found that BB pacing achieved a higher percentage of left ventricular synchronized pacing compared with RAA pacing, offering potential advantages for patients undergoing cardiac resynchronization therapy.

Conclusion
BB pacing represents a new approach for reducing the incidence of AF. Compared with RA septal or RAA pacing, BB pacing has been associated with reductions in AF burden, recurrence, and initiation, and evidence suggests BB pacing is preferable to RAA pacing.

Utilizing the heart’s intrinsic conduction system for pacing (the interstates, going fast!) may be preferable to pacing random muscle tissue (the local roads, always slower!). Conduction times are decreased, and fewer pacing iatrogenic complications may occur. BB pacing represents another promising strategy to reduce the burden of AF in patients requiring pacing. The field of pacing continues to evolve, and further large-scale studies are needed to confirm these findings. 

Disclosures: The author has completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest and reports stock in Medtronic, Johnson & Johnson MedTech, and Boston Scientific.

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