Anatomic and electrophysiologic evaluation of a right lateral atrioventricular Mahaim fiber

Unusual source of tachycardia in an adolescent

Mahaim fiber tachycardia is an uncommon cause of palpitations among the pediatric population. This case report describes an adolescent female who presented with recurrent episodes of tachycardia with chest pain and dizziness. Her ECG showed tachycardia with wide QRS complexes and left bundle branch block pattern. Repeat ECG after adenosine treatment revealed sinus rhythm with persistence of the left bundle branch block pattern. Metoprolol was started however she continued to have episodes of sustained tachycardia.

Electrophysiologic study then confirmed the diagnosis of Mahaim fiber tachycardia. Treatment was successful with mapping of the accessory pathways followed by radiofrequency ablation.

Catheter ablation of ventricular insertion of Mahaim fiber using noncontact mapping system in a patient with mirror-image dextrocardia

We report a case of mirror-image dextrocardia with antidromic atrioventricular reciprocating tachycardia via the Mahaim fiber. Using the noncontact mapping system, arborized ventricular insertion of the Mahaim fiber was identified and successfully ablated.