Over recent years, in response to the widespread use of contact force (CF) ablation catheters for the treatment of atrial fibrillation, numerous studies have sought to assess their performance, effectiveness, and safety.
Randomised trials have proven the non- inferiority of CF catheters compared to non-CF catheters in terms of safety and long-term efficacy and have shown a correlation between the use of optimal force and higher success rates. However, whether these results can be extrapolated to a real-world setting with operators of varied experience levels across centres with diverse volumes remains unknown. This study is a subset analysis of the ABLATOR registry, which is a prospective, multicentre, international registry that included 2,035 patients who were indicated for an atrial fibrillation ablation using different St. Jude Medical technologies. Patient enrolment took place from December 2014–June 2016. The purpose of this sub-study was to evaluate the performance of CF ablation catheters, specifically the TactiCath™ Quartz catheter (Abbott, Lake Bluff, Illinois, USA), in patients undergoing de novo paroxysmal atrial fibrillation ablation. From the overall population of the ABLATOR registry, 473 subjects were included in this subanalysis and 460 completed the follow-up (approximately 3% lost to follow-up).
The results of this study are comparable to, or better than, the success rates reported in randomised trials investigating the use of other CF ablation catheters, such SMART-AF (66%),1 FIRE and ICE (64%),2 and TOCCASTAR (68%).3 The clinically relevant freedom from recurrence at 1-year follow-up was 76.9%, which decreased to 71.6% when patients on antiarrhythmic drugs were excluded. Serious adverse events affected 3.2% of this registry. Only 1 oesophageal fistula was reported (0.2%), 1 vascular complication (0.2%), and 9 patients had pericardial effusion, 7 of whom had cardiac tamponade (1.5%). These results are in keeping with the SMART-AF results, which reported that cardiac tamponade occurred in 2.5% of the subjects.1 Despite similarity to the SMART-AF trial, these results are higher than expected based on the current clinical experience. Most of the previous studies enrolled patients during the initial years of CF catheter use, when the optimal CF to achieve durable lesions for successful isolation of the pulmonary veins had not yet been defined and the safety profile had not been optimised.
Mansour et al.4 recently reported on a registry of 41,709 patients who underwent atrial fibrillation using the TactiCath Quartz catheter. The overall rate of complications was reported as 0.481% and cardiac perforations were reported in 0.281% of the subjects. This progressive reduction in the complication rates was comparable with the initial SMART-AF and TOCCASTAR studies; however, the discrete improvement in success rates may be attributed to an increase in operator experience and a better understanding of the use of these technologies.
In conclusion, real-world efficiency, effectiveness, and safety of the TactiCath Quartz catheter for paroxysmal atrial fibrillation ablation has been clearly proven in this registry, beyond the results of randomised trials. The importance of registries in opposition to randomised trials is based on the need to know the real-world outcomes in varied centres with different levels of operator expertise.