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Antidromic Atrioventricular Re-Entrant Tachycardia via Left Anterolateral Accessory Pathway With Long Conduction Time

Year: 2025

Type: article

Abstract: BACKGROUND: Left-sided atrioventricular accessory pathways (APs) with long anterograde conduction time are uncommon causes of wide-QRS tachycardia. CASE SUMMARY: A 21-year-old woman presented with recurrent wide-QRS tachycardia with right bundle branch block morphology. Baseline electrocardiogram and intracardiac recordings showed no pre-excitation. Retrograde conduction over the AP was absent. Antidromic atrioventricular re-entrant tachycardia (AVRT) was inducible. During sinus rhythm, retrograde mapping at the left anterolateral mitral annulus identified a discrete AP potential. Radiofrequency ablation at this site eliminated the potential and rendered the tachycardia noninducible. The patient remained asymptomatic at the 1-year follow-up. DISCUSSION: The findings support antidromic AVRT mediated by a short left anterolateral AP with long conduction time. Definitive decremental conduction was not proven owing to lack of atrial-insertion pacing or adenosine testing and absent coronary sinus activation changes. Surface electrocardiographic features favored pre-excited supraventricular tachycardia over ventricular tachycardia. TAKE-HOME MESSAGES: Left-sided APs with long conduction time can mediate antidromic AVRT. Targeting a discrete pathway potential at the suspected site guides successful ablation.

Source: JACC Case Reports

DOI: 10.1016/j.jaccas.2025.106295

Authors: Seongjin Park, Hyo Jin Lee, Juwon Kim, Kyoung-Min Park

Institutions: Samsung Medical Center, Sungkyunkwan University, Samsung Changwon Hospital

Language: English

Topic: Cardiac Arrhythmias and Treatments

Subfield: Cardiology and Cardiovascular Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $850