The Bachmann Bundle and Interatrial Conduction

The cardiac conduction system (CCS) is responsible for generation and systematic conduction of cardiac impulses. The Bachmann Bundle (BB), considered one of its several accessory impulse-conducting pathways, plays a fundamental role in interatrial conduction. Delay in this pathway leads to prolongation of the P wave on the electrocardiogram (interatrial delay or block), which in turn is a precursor for atrial tachyarrhythmias, mainly atrial fibrillation and significant left atrial electromechanical dysfunction. As such, the magnitude of its sequelae has necessitated a flurry of investigations that have been targeted toward its prevention and management. Although current studies on the use of angiotensin-converting enzyme inhibitors and atrial pacing have indeed shown some promise, it would be shortsighted to overlook and circumvent the actual underlying lesion-BB abnormality. Thus, a thorough understanding of the CCS and interatrial conduction is essential. We review current literature on the BB and discuss potential mechanisms that affect its conduction.