Irregular narrow QRS complex tachycardia with intermittent atrioventricular dissociation: What is the mechanism?

A 39-year-old woman with frequent palpitations was referred for radiofrequency ablation. A baseline 12-lead electrocardiogram showed normal sinus rhythm. At baseline, atrio-His (AH) and His-ventricular (HV) intervals were 80 and 45 ms, respectively. This article is protected by copyright. All rights reserved.