What is Bachmann Bundle Pacing?

Bachmann’s bundle is located at the upper part of the interatrial septum, near the junction of the superior vena cava and the right atrium. It is the conduction bundle to the left atrium. Pacing the Bachmann bundle area can improve the atrial electrical activation pattern and reduce the risk of atrial fibrillation compared to the conventional right atrial appendage pacing by up to 40% [1]. Bachmann bundle pacing can be considered more ‘physiological’ as it targets the natural pathway of electrical conduction in the atria. Bachmann bundle pacing can result in a narrower P wave similar to the normal sinus P wave, indicating more efficient atrial activation. This could potentially lead to better atrial synchrony.

It has been mentioned that Bachmann bundle pacing could decrease the risk of cardiac perforation compared to right atrial appendage pacing due to the thickness of septal portion of the lower SVC [1]. Though the endocardial electrograms at the site are of low amplitude, atrial tissue immediately posterior to the Bachmann bundle has ample voltage typically above 1 mV. Lead implantation for Bachmann bundle pacing can be technically challenging. P wave amplitude guided approaches can improve the success.

In this context, three important downsides of right atrial appendage pacing have been described. Right atrial appendage tissue has trabeculae and the the intervening regions are thin and can be easily perforated. Appendage leads can account for almost half of all lead perforations. As the location is near the right ventricular outflow tract, ventricular signals can cause oversensing in atrial channel. Thirdly, as discussed initially, wider P wave with right atrial appendage pacing is associated with increased risk of atrial fibrillation. The risk has been described as directly proportional to the degree of widening of P wave and the burden of right atrial appendage pacing [1].

Reference

1. Lustgarten DL, Habel N, Sánchez-Quintana D, Winget J, Correa de Sa D, Lobel R, Thompson N, Infeld M, Meyer M. Bachmann bundle pacing. Heart Rhythm. 2024 Sep;21(9):1711-1717. doi: 10.1016/j.hrthm.2024.03.1786. Epub 2024 Mar 27. PMID: 38552731.