A case of diagnostic challenge: Wide QRS complex tachycardia caused by rare etiologies

Rapid atrioventricular nodal non-reentrant tachycardia (DAVNNT) with intraventricular differential conduction-induced wide QRS tachycardia (WCT) is often misdiagnosed as ventricular tachycardia (VT) due to its distinctive atrioventricular conduction characteristics, making timely and accurate diagnosis and treatment challenging. This case report describes a 42-year-old female patient who presented with recurrent palpitations, with a dynamic electrocardiogram documenting a WCT that mimicked VT. Esophageal electrophysiological studies revealed a 1:2 atrioventricular conduction pattern. Intracardiac electrophysiological examination confirmed the diagnosis of DAVNNT, which was successfully treated with radiofrequency ablation. This case highlights that WCT with fewer P waves than QRS complexes can occur in DAVNNT, similar to VT. By logical inference a 1:2 atrioventricular conduction pattern, together with suspected interpolated ventricular or junctional premature contractions exhibiting variable QRS morphology, may serve as key diagnostic clues for DAVNNT.