Radiofrequency catheter ablation of two accessory pathways with different unidirectional conduction properties.

Simultaneous occurrence of narrow and broad QRS complex tachycardias in patients with WPW syndrome usually indicates a macroreentry in an orthodromic atrioventricular reentry-tachycardia using the AV node as antegrade and the accessory pathway as retrograde conduction and vice versa in an antidromic circuit. We report on a 32-year-old woman with WPW syndrome presenting with both a narrow and a broad QRS complex tachycardia using two accessory pathways with different unidirectional conduction properties in combination of an exclusively antegrade conducting AV node. This case report describes conventional mapping techniques and ablation of this unusual entity of a WPW syndrome.