CRITERIA PREDICTIVE OF SUCCESS OF RADIOFR EQUENCY ABLATION OF NODAL REENTRANT TACHYCARDIA

Endocavitary catheter ablation by radiofrequency energy applied on the slow pathway is an effective method of treatment of nodal reentrant t achycardias. The aim of this report was to determine the criteria pred ictive of success during radiofrequency ablation of the slow pathway g uided by the presence of slow potentials. Thirty-five patients (21 wom en, 14 men, mean age 44 +/- 14 years) with frequent attacks of junctio nal tachycardia were studied. After confirmation of the diagnosis by e lectrophysiological investigation, radiofrequency energy was delivered at a site characterised by the presence of slow potentials between th e atrial (A) and ventricular (V) potentials. The criteria investigated at each site were : before application : A/V ratio; amplitude of A an d V : maximum A/minimum A ratio; amplitude and duration of the A poten tial; during ablation: radiological stability of the catheter position and occurrence of a junctional rhythm. All 35 patients had successful procedures with no inducible tachycardia at the end of the procedure. The slow pathway was destroyed in 20 cases (57 %) with no complicatio n of atrioventricular block. The duration of the A potential was longe r in the successful cases (56 +/- 16 vs 48 +/- 14 ms : p = 0.04). The appearance of junctional rhythm and catheter stability during the proc edure were predictive of success (79 % vs 48 %; p = 0.02; 74 % vs 43 % ; p = 0.01). The authors concluded that an ablation site with a long d uration A potential and a slow potential is a good target. In addition , ablation should be started when the catheter is radiologically stabl e and should not be interrupted in the absence of a junctional rhythm.