Introduction: Cooling the catheter tip either passively with increased tip size or actively during radiofrequency catheter ablation (RFCA) has been shown in canine thigh preparations to create larger lesions than standard catheter tips, yielding a theoretical advantage for improving the outcome of RFCA for intra-atrial reentrant tachycardia (IART).
Methods and results: The pediatric RFCA database at the Medical University of South Carolina was reviewed for RFCA of IART in patients with structural heart disease. From a total of 31 patients who underwent procedures during the study period, 8 patients in whom ablation with conventional ablation techniques failed and who went on to passive cooling with an 8-mm tip catheter or active cooling with an internally cooled-tip catheter were studied. Power delivery was greater but temperature and impedance were lower during cooled ablation than during conventional ablation. Passive cooling was associated with higher power than active cooling. These changes in RF biophysical characteristics were associated with successful elimination of 11 of 13 IART circuits in 7 of 8 patients.
Conclusion: Cooling during RF ablation of atrial tachycardia clearly yielded greater power delivery in vivo and was associated with success.