Successful sequential radiofrequency catheter ablation of anatomically discrete antegrade and retrograde accessory pathway conduction in the Wolff-Parkinson-White syndrome.

Histopathologically, accessory atrioventricular (AV) pathways comprise tiny strands of working myocardium that traverse the AV groove and link between the atrial and ventricular myocardium. Antegrade and retrograde conduction in bidirectional accessory pathways have generally been considered to occur along the same fibers. This report details the successful catheter ablation of a left free wall accessory pathway with radiofrequency energy. Antegrade and retrograde conduction of the pathway were abolished sequentially by separate episodes of energy delivered at anatomically discrete though closely adjacent sites along the mitral annulus. This finding raises the interesting possibility of anatomic "compartmentalization" of antegrade and retrograde conduction along an accessory pathway.