Catheter atrioventricular junction ablation for recurrent supraventricular tachycardia with nodoventricular fibers

Patients with nodoventricular (Mahaim) fibers are predisposed to the development of a variety of arrhythmias, which are usually amenable to pharmacologic management.¹ Closed-chest catheter atrioventricular (AV) junction albation, which has been shown to be an effective treatment for supraventricular tachycardia,^2,3 has recently been applied in a patient with tachycardia involving a Mahaim fiber.⁵ We report observations in 2 cases in which tachycardia was effectively controlled using this technique, including 3-year follow-up of nodoventricular fiber conduction in 1 patient and absence of retrograde conduction in both patients. The inability of the nodoventricular fibers to conduct retrogradely has not been previously described.