Radiofrequency catheter ablation of two right Mahaïm-like accessory pathways in a patient with Ebstein's anomaly.

A 17-year-old woman with Ebstein's anomaly and recurrent episodes of antidromic tachycardia with two distinct morphologies is described. The tachycardias were produced by two separate Mahaïm-like accessory pathways. These were localized by their activation potentials at the anterolateral ventricular margin of the tricuspid annulus and ablated in a single session using radiofrequency current.