RADIOFREQUENCY ABLATION OF ACCESSORY ATRI OVENTRICULAR PATHWAYS

Since its introduction at the beginning of the 1980s, radiofrequency a blation of accessory atrioventricular pathways has become method becau se of its excellent results and the indications have increased to case s in which only symptomatic improvement is the objective. These advanc es have been made possible by technical innovations to the generators of the radiofrequency current and, above all, to the ablation catheter s which enable mapping nearly all the perimeter of the atrioventricula r rings and reach all the accessory pathways irrespective of their sit e. The approach depends on the localisation of the accessory pathway b ut the criteria of mapping are the same : detection of a specific acce ssory pathway potential, precession or concordance (depending on the t opography) of the initial peak of the endocavitary ventriculogramme an d the onset of the delta wave on the surface EGG. QS morphology of the ventriculogramme on monopolar recording, shortest VA' interval in ort hodromic reciprocating tachycardia for latent kent bundles. In special ised centres, the global success rate is 90 to 98 % but certain sites, especially the right lateral pathways, are more difficult to attain. The complication rate is about 4 % but it tends to decrease with the e xperience of the operating teams and close monitoring of the patients. However, there persists an uncertainty concerning potentially arrhyth mogenic effects of the lesions induced which justifies restricting the indications in young children.