Catheter ablation of ventricular tachycardia related to coronary heart disease. Defining the target.

O ver the past decade, radiofrequency catheter ablation has become the preferred curative treatment for the most common forms of supraventricular tachycardias.1-3 These tachyarrhythmias are produced by different reentrant mechanisms. In the case of accessory atrioventricular pathways,4-5 all the components of the reentry circuit had already been functionally and anatomically well identified before catheter ablation was introduced. Radiofrequency catheter ablation uses the accessory pathway as a target to disrupt this reentrant substrate with an excellent success rate reaching 89-99% in the most experienced centers,1-3 but the technique necessitates a laborious and time-consuming mapping procedure because of the small size of the lesion. In the case of atrioventricular nodal reentrant tachycardia, the reentrant substrate was less well defined anatomically before the advent of radiofrequency catheter ablation. The existence of two functional pathways (slow and fast) had been well demonstrated with programmed stimulation,6 but the anatomic location of these pathways, whether both intranodal or not, was undetermined.7 Due to the small extent of the lesions caused by radiofrequency energy,