Atrio‐Hisian Fibers Anatomy and Electrophysiology

Abstract

In our study, the lack of lengthening of the PR interval in spite of progressively premature atrial stimulation connected with the presence of atrio-hisian bypass tract.

Variants of accessory pathways

“…Originally described by Claude Brechenmacher in 1975, atrio‐Hisian tracts are a connection between the atrium (original description interatrial septum) bypassing the AV node and inserting into the His bundle . First described in patients with sudden cardiac death, it is now known to be associated with rapid tachycardia and syncope.…”

“…Pathologic demonstration reveals an abnormal central fibrous body. The central fibrous body either is absent or thins as it extends from the compact AVN to the His bundle, and the atrial pathway, penetrates the upper margin of the left side of the His bundle through the abnormal central fibrous body (Figure ) . The His insertion has been seen to insert in the proximal His as well as more distally at the site of branching into the right and left bundle …”

“…The best indicator seen during electrophysiology study was lack of or minimal lengthening of the PR interval with atrial pacing or progressively premature atrial extrastimuli. Using programmed atrial extrastimuli at shorter and shorter cycle lengths, the spike‐R interval does not increase while the P‐spike interval is progressively shortened …”

“…Sudden death is thought to be from atrial arrhythmias and enhanced AV conduction associated with rapid ventricular rates because of the nodal bypass . Once the diagnosis is made, urgent His bundle ablation and pacemaker insertion is recommended . To our knowledge there are no reports of ablation alone without permanent pacing as being effective.…”

“…Variant accessory pathways include atriofascicular (A‐F), nodofascicular (NF), nodoventricular (NV), atrio‐Hisian, and fasciculoventricular (FV) pathways . A‐F pathways are the most common with others occuring rarely.…”