Aims: In a prospective, randomized study, the effect of temperature control on radiofrequency catheter ablation was compared in 69 patients undergoing atrioventricular nodal modification (n = 32) or ablation of an accessory pathway (n = 37).
Methods and results: Thirty-five patients were randomized to temperature control, 34 to manually delivered radiofrequency ablation. The success rate was 92.5% for accessory pathway ablation and 100% for atrioventricular nodal modification. Mapping duration was significantly reduced only in patients undergoing atrioventricular nodal modification. The number of applications was higher for manually delivered ablation in patients undergoing atrioventricular nodal modification (5.6 +/- 1.1 vs 1.9 +/- 0.4, P = 0.004) as was the cumulative energy delivered (5034 +/- 1008 vs 2054 +/- 517 W, P = 0.013) whereas the mean power per application was higher with temperature control (41.4 +/- 1.8 vs 34.1 +/- 1.1 W, P = 0.002). No significant differences in these parameters were found in patients undergoing accessory pathway ablation. Coagulum formation on the catheter tip was observed more often with manually delivered ablation 5.3% vs 0.9%, P = 0.026). The success rate with the initially randomized application mode was higher for temperature control (94.3 vs 61.8%, P = 0.003).
Conclusions: Temperature control during radiofrequency current ablation significantly reduces mapping duration, necessary applications and cumulative energy in atrioventricular nodal modification, but not accessory pathway ablation. Coagulum formation on the catheter tip still occurs but is significantly reduced compared to manually delivered radiofrequency current.