EFFICAS I study yields new contact force guidelines in catheter ablation treatment of AF

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Results from the EFFICAS I, a prospective multicentre study sponsored by Endosense, have led to the development of guidelines for target and minimum contact force, as well as minimum force time integral, during the catheter ablation treatment of paroxysmal atrial fibrillation.

Published in the April 2013 issue of the American Heart Association journal Circulation: Arrhythmia and Electrophysiology, the newly created guidelines call for a contact force target of 20g (and minimum contact force of 10g) and minimum force time integral of 400gs per individual ablation lesion.


The results of EFFICAS I demonstrated the importance of force time integral in the long-term effectiveness of catheter ablation for treating paroxysmal atrial fibrillation. The study’s authors also concluded that Endosense’s proprietary force time integral parameter, which measures the accumulated energy delivered per ablation, combined with contact force over the duration of the ablation, is a strong predictor of ablation success. Furthermore, the study illustrated that not only the average, but the most inferior ablation value predicts the long-term effectiveness of the procedure. Therefore, contact force guidance using force time integral is critical in creating every single ablation lesion.


According to the publication, pulmonary vein isolation is the most prevalent approach for catheter ablation of paroxysmal atrial fibrillation. Long-term success of the procedure is diminished by arrhythmia recurrences occurring predominantly due to reconnections in previously isolated pulmonary veins. The likelihood of recurrence increases in the presence of gaps in the isolation line. EFFICAS I was undertaken to investigate the exact relationship between contact force and force time integral parameters measured during ablation and the incidence of isolation gaps in the pulmonary vein line measured invasively during a three-month follow-up electrophysiologic study.


“As hypothesised, the results of EFFICAS I clearly showed that pulmonary vein reconnection is contingent on the contact force used during initial catheter ablation treatment,” said the study’s primary author, Petr Neuzil from the Department of Cardiology at Na Homolce Hospital in Prague, Czech Republic. “The study also confirms the immense value of Endosense’s force time integral parameter and offers valuable guidelines that may lead to a new standard of care.”


EFFICAS I was a 46-patient, single-arm, prospective, multicentre European clinical trial. Investigators performed the procedure with Endosense’s TactiCath, the first force-sensing catheter to give the electrophysiologist a real-time, objective measure of contact force during the catheter ablation procedure. While contact force and force time integral was recorded, investigators were blinded to these measurements during the procedures.


The optimal contact force parameters identified at the conclusion of EFFICAS I are currently being evaluated in Endosense’s EFFICAS II study, which will allow operators to view contact force and force time integral in real-time during the catheter ablation procedures. EFFICAS II will measure reduction in pulmonary vein gaps as well as procedural improvements as compared to EFFICAS I.


In the United States, the TactiCath is an investigational device.