A single Mahaim fiber causing both antidromic and orthodromic reciprocating tachycardia.

We describe the case of a 56-year-old woman referred for electrophysiological (EP) testing for medically refractory supraventricular arrhythmias. During the EP study, the patient was found to have a right free wall atriofasicular (Mahaim type) accessory pathway and an inducible left bundle morphology preexcited tachycardia secondary to antidromic reciprocating tachycardia. The patient also had an inducible narrow complex orthodromic reciprocating tachycardia (ORT).

Proarrhythmia of circumferential left atrial lesions for management of atrial fibrillation.

Background: After circumferential ablation for atrial fibrillation, new onset left atrial flutter (LA Flr) may occur. This study assessed the relationship between induced and clinical episodes of LA Flr, the rate of spontaneous resolution of LA Flr, and the proarrhythmic effect of circumferential ablation.

Methods And Results: A total 112 patients underwent circumferential LA ablation for atrial fibrillation.