SLOW AV NODAL PATHWAY ABLATION UTILIZING A UNIQUE TEMPERATURE-CONTROLLED RADIOFREQUENCY ENERGY SYSTEM

Thiry-nine consecutive patients with symptomatic AV nodal reentrant ta chycardia (AVNRT) underwent temperature guided slow AV nodal pathway a blation (group 1). Forty-three consecutive patients undergoing nontemp erature guided slow AV nodal pathway ablation late in our experience c ompose she control population (group 2). Slow pathway ablation was ach ieved in all patients of both groups. The mean fluoroscopy and ablatio n times for group 1 were significantly shorter than for group 2 (26.1 +/- 14.9 vs 33.9 +/- 18.9 min, P < 0.05; 19.9 +/- 12.1 vs 30.9 +/- 23. 3 min, P less than or equal to 0.02). There were no episodes of coagul um formation in group 1, while there were 15 episodes (7.1% of energy applications) in group 2 (P = 0.0006) despite a significantly higher a pplied power in group 1 (53.4 +/- 25.1 vs 35.6 +/- 9.5W, P = 0.0001). Successful energy applications were associated with significantly high er temperatures than unsuccessful applications in group 1 (55.6 degree s +/- 5.8 degrees C vs. 52.9 degrees +/- 6.8 degrees C, P less than or equal to 0.03). The minimum temperature required for successful ablat ion was 48 degrees C for two patients (5%) and was greater than or equ al to 50 degrees C for the remainder of patients (37/39[95%]). The cat heter ablation system used in this study was safe, effective, and prev ented coagulum formation while delivering relatively high power. In ad dition, shorter ablation times and radiation exposure were seen with t his system. Although successful energy applications and the production of junctional rhythm were associated with higher achieved temperature s, temperature alone did not predict either endpoint. Future prospecti ve, randomized trials are needed to confirm these findings and further evaluate the value of temperature monitoring.