A prospective, randomized comparison of temperature-controlled vs manually delivered radiofrequency catheter ablation in patients undergoing atrioventricular nodal modification or accessory pathway ablation

AIMS: In a prospective, randomized study, the effect of temperaturecontrol on radiofrequency catheter ablation was compared in69 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 successrate was 92·5% for accessory pathway ablation and 100%for atrioventricular nodal modification. Mapping duration wassignificantly reduced only in patients undergoing atrioventricularnodal modification. The number of applications was higher formanually delivered ablation in patients undergoing atrioventricularnodal modification (5·6 ± 1·1 vs 1·9± 0·4, P=0·004) as was the cumulative energydelivered (5034 ± 1008 vs 2054 ± 517 W, P=0·013)whereas the mean power per application was higher with temperaturecontrol (41·4 ± 1·8 vs 34·1 ±1·1 W, P=0·002). No significant differences inthese parameters were found in patients undergoing accessorypathway ablation. Coagulum formation on the catheter tip wasobserved more often with manually delivered ablation 5·3%vs 0·9%, P=0·026). The success rate with the initiallyrandomized application mode was higher for temperature control(94·3 vs 61·8%, P=0·003). CONCLUSION: Temperature control during radiofrequency current ablation significantlyreduces mapping duration, necessary applications and cumulativeenergy in atrioventricular nodal modification, but not accessorypathway ablation. Coagulum formation on the catheter tip stilloccurs but is significantly reduced compared to manually deliveredradiofrequency current.