Mahaim-mediated tachycardia using at times the atrioventricular node and other times a left lateral accessory pathway

Electrophysiologic diagnosis of narrow and wide complex tachyarrhythmias

Establishing the precise mechanism of cardiac arrhythmias in the electrophysiology laboratory is one of the main requisites for a successful and safe ablation. This article provides an organized approach to the differential diagnosis of narrow and wide complex tachycardias based on the analysis of electrical activation patterns, followed by specific pacing maneuvers in each case.

Right-sided Mahaim-mediated tachycardia combined with atypical atrioventricular nodal reentrant tachycardia and left free wall accessory pathway: A case report

A 37-year-old man was admitted to our hospital with paroxysmal palpitation for half year. A previous electrogram showed a narrow complex tachycardia. Electrophysiologic study (EPS) found a concealed left-sided free wall pathway accessory. In addition, a transseptal approach was used for radiofrequency ablation. After successful ablation, EPS induced a wide complex tachycardia and a narrow complex tachycardia. The wide complex tachycardia was diagnosed as a right-sided Mahaim fiber atriofascicular accessory pathway, and the narrow complex tachycardia was diagnosed as atypical atrioventricular nodal reentrant tachycardia (AVNRT). Then, the right-sided Mahaim fiber atriofascicular accessory pathway and atypical AVNRT were successfully ablated. Herein, we report a rare case of a concealed left-sided accessory pathway combined with a right atriofascicular Mahaim fiber and atypical AVNRT.