Background: Large-tip radiofrequency ablation (RFA) catheters (LTC), 8 mm and 10 mm tip catheters, are both capable of creating large lesions and are more effective than conventional catheters for cavotricuspid isthmus (CTI) ablation. It is not clear whether complete CTI block can be achieved more efficiently using an 8 mm or a 10 mm catheter. In the absence of randomised clinical trials, we conducted a propensity-score-matched comparison of 8 mm versus 10 mm LTC amongst patients undergoing a CTI ablation.
Methods and Results: From a total cohort of 402 patients who underwent LTC CTI RF ablation for typical atrial flutter since May 2012, 322 patients with no previous history of CTI ablation and with a follow-up duration ≥6 months were included and stratified according to the tip diameter of the RF catheter: 8 mm versus 10 mm. A final study population of 121 patients who underwent RFA of CTI using an 8 mm RF catheter were compared with 121 propensity-score matched patients treated with a 10 mm catheter. A 20 minute waiting period was observed in all cases.
Results: Bidirectional isthmus block was achieved in all patients. Procedure duration was shorter for 10 mm LTC (52 minutes (IQR: 40–73) versus 68 minutes (IQR: 50–86), p< 0.001) than the 8 mm LTC. The median duration of RFA to achieve CTI block was 9.3 minutes (IQR: 6.1–14.1) with a 10 mm LTC and 11.2 minutes (IQR: 7.2– 18.4) with an 8 mm LTC (p= 0.018). The median follow-up duration was 36 months (IQR: 20–56). 119/121 patients (98.3%) in the 10 mm and 119/121 patients (98.3%) in the 8 mm groups remained free from AFL to the end of the follow up period. One right femoral artery pseudo-aneurysm occurred in the 10 mm group; there were no other complications recorded.
Conclusions: Complete CTI block is achieved more rapidly using a 10 mm LTC compared to an 8 mm LTC and with a similar clinical efficacy. Reducing the procedure duration may improve patient experience in addition to improving the workflow in a busy cardiac catheter laboratory.