Atrioventricular node reentry that utilizes triple nodal pathways

Multiple atrioventricular nodal pathways in humans: electrophysiologic demonstration and characterization

INTRODUCTION

Multiple AV nodal pathway physiology can be demonstrated in certain patients with clinical AV reentrant tachycardia.

METHODS AND RESULTS

Evidence suggesting multiple AV nodal pathway conduction was present in seven (two males; age range 15 to 75 years) of 78 patients (9%) who underwent electrophysiologic studies for AV nodal tachycardia. The presence of two discrete discontinuities in the AV nodal conduction curves suggested triple AV nodal pathway conduction. Detailed mapping of their retrograde atrial activation sequence was performed along the tricuspid annulus from the coronary sinus ostium to the His-bundle electrogram recording site. Three zones (anterior, middle, and posterior) correspond to the upper, middle, and lower third of the triangle of Koch, respectively. The fast pathway exits were determined as anterior (4/7) or middle (3/7), the intermediate pathway exits as middle (4/7) or posterior (3/7), and the slow pathway exits as middle (1/7) or posterior (6/7). Other evidence suggesting multiple AV nodal pathway conduction includes: (1) triple ventricular depolarizations from a single atrial impulse; (2) sequential dual ventricular echoes; (3) spontaneous transformation between the slow-fast and fast-slow forms of AV nodal reentrant tachycardia; and (4) persistent cycle length alternans during AV nodal reentrant tachycardia. In four patients, all three pathways were shown to be involved in AV nodal echoes or reentrant tachycardia.

CONCLUSION

Multiple AV nodal pathways are not uncommon and can be identified by careful electrophysiologic elucidation and mapping technique.

Triple atrioventricular nodal pathways can be masked

In summary, CL modulates the dispersion in refractoriness of triple nodal pathways by causing greater changes in refractoriness in the slower pathways and thus determines the feasibility of manifestation.

Radiofrequency ablation for the fast pathway of atrioventricular node reentry. Evidence for partial damage to the fast and lower common pathways

Radiofrequency ablation was attempted in a 30-year-old woman with atrioventricular (AV) node reentry of the common variety. Energy was delivered to ablate a fast pathway. After energy delivery, the atrio-His interval prolonged following transient AV node block. Retrograde conduction was no longer present. However, dual AV nodal physiology and AV node reentry with similar retrograde atrial activation sequence could be shown post-ablation. These observations suggest that both fast and lower common pathways were partially damaged by ablation.

Atrioventricular junctional reentrant tachycardia utilizing multiple retrograde fibers during ablation of the slow pathway

This report deals with a patient with atrioventricular (AV) reentrant junctional tachycardia who, during radiofrequency ablation of her slow pathway, developed both anterior and posterior type of slow-fast atrioventricular nodal reentry; in both tachycardias different fibers were alternately utilized for retrograde conduction, thus resulting in alternating tachycardia cycle lengths. This observation provides further evidence in favor of the multifiber structure of the AV node in patients with AV reentrant junctional tachycardia.