Multiple anterograde atrioventricular node pathways in patients with atrioventricular node reentrant tachycardia

Area of Science:

• Electrophysiology
• Cardiology
• Cardiac Electrophysiology

Background:

• Multiple anterograde atrioventricular (AV) node pathways are suggested by AV node conduction curve discontinuities.
• Their role in AV node reentrant tachycardia (AVNRT) initiation and maintenance remains unclear.
• Anatomic sites of these pathways have not been previously reported.

Purpose of the Study:

• To investigate electrophysiologic characteristics of multiple anterograde slow AV node pathways.
• To identify possible anatomic sites of these pathways.
• To compare findings with dual anterograde AV node pathways.

Main Methods:

• Electrophysiologic study and radiofrequency ablation in 500 consecutive AVNRT patients.
• Group I: 26 patients with triple or more anterograde AV node pathways.
• Group II: 474 patients with dual anterograde AV node pathways (451) or without (23).

Main Results:

• In triple pathway patients, AVNRT initiation involved one (3), two (9), or three (9) slow pathways.
• Radiofrequency ablation successfully eliminated inducible AVNRT in all patients.
• Multiple slow pathways were simultaneously ablated at single sites in 42.3% and at different sites in 30.7% of Group I patients.
• Group I patients exhibited longer tachycardia cycle length, poorer retrograde conduction, and higher incidence of multiple AVNRT types.

Conclusions:

• Multiple anterograde AV node pathways are prevalent in AVNRT patients.
• Not all identified slow pathways actively participate in tachycardia initiation/maintenance.
• Radiofrequency catheter ablation is a safe and effective treatment for AVNRT by eliminating critical slow pathways.