Anatomic, electrical, and hemodynamic characterization of Bachmann bundle in the swine heart

BACKGROUND

Bachmann bundle area (BBA) pacing is an attractive alternative to traditional right atrial appendage (RAA) pacing, but its hemodynamic benefits are poorly understood.

OBJECTIVE

The purpose of this study was to evaluate hemodynamic effects of BBA pacing and structural characteristics of the aligned myocytes within BBA.

METHODS

Five swine were subjected to volume overload by intravenous infusion of 3 L of 0.9% saline solution during 30 minutes. Medtronic 3830 pacing leads were placed in the RAA and BBA. Rates were alternated between the 2 sites at 110, 120, and 130 beats/min, with the acquisition of left ventricular pressure-volume loops. Anatomies were formalin-fixed and treated with a 7.5% iodine solution to delineate contractile myocardium. The specimens underwent a perfused contrast-enhanced micro-computed tomography protocol with iodine to identify soft tissue differences in the tissue.

RESULTS

Our findings revealed atrial synchrony with BBA pacing compared with RAA pacing. BBA pacing reduced average P-wave duration by 27 ms, accompanied by increased left ventricular stroke volume across pacing speeds (23%, 17%, and 15% at 110, 120, and 130 beats/min, respectively). Micro-computed tomography scans depicted orientations of the Bachmann bundle.

CONCLUSION

Through this study, we have achieved a comprehensive hemodynamic characterization and anatomic reconstruction of Bachmann bundle in a swine model subjected to volume overload. The hemodynamic improvements of BBA pacing relative to RAA pacing underscore the potential of BBA pacing as an alternative site for atrial pacing. This understanding of atrial physiology may inform clinical interventions to optimize pacing strategies.

Alternative atrial pacing site to improve cardiac function: focus on Bachmann's bundle pacing

Pacing from the right atrial appendage (RAA) prolongs the P wave duration and can induce interatrial and especially left-sided atrio-ventricular dyssynchrony. Pacing from Bachmann's bundle closely reproduces normal physiology and has the potential to avoid the electromechanical dysfunction associated with conventional RAA pacing. Interatrial conduction delay is associated with an increased risk of stroke, heart failure, and death. In addition to a reduction in atrial fibrillation, Bachmann's bundle pacing has emerging applications as a hemodynamic pacing modality. This review outlines the pathophysiology of atrial conduction disturbances and their potential remedies and provides the reader with a practical guide to implementing Bachmann's bundle pacing with an emphasis on the recapitulation of normal electrical and mechanical function.

Cardiac pacing and defibrillation in children and young adults

The population of children and young adults requiring a cardiac pacing device has been consistently increasing. The current generation of devices are small with a longer battery life, programming capabilities that can cater to the demands of the young patients and ability to treat brady and tachyarrhythmias as well as heart failure. This has increased the scope and clinical indications of using these devices. As patients with congenital heart disease (CHD) comprise majority of these patients requiring devices, the knowledge of indications, pacing leads and devices, anatomical variations and the technical skills required are different than that required in the adult population. In this review we attempt to discuss these specific points in detail to improve the understanding of cardiac pacing in children and young adults.