Contact Force-Sensing Ablation Study Supports 10 gram Target

This week sees the Heart Rhythm Society holding its 35th Annual Scientific Sessions in San Francisco. St. Jude Medical, Inc., has used the event at which to announce results of the TOCCASTAR clinical trial. Results from the first prospective, randomized study of contact-force ablation technology for the treatment of paroxysmal atrial fibrillation (AF) met primary endpoints and supplement the growing body of evidence that supports the safety and effectiveness of contact-force ablation technology.

Background

Pardoning the pun in advance of using it, the current buzzphrase in cardiac tissue ablation for treatment of AF is contact force sensing. During the procedure, if too little force is applied, there is a risk of incomplete lesion formation that could result in AF recurrence, potentially requiring additional treatments. If too much force is applied, there is a risk of tissue injury, which can lead to serious procedure-related complications. Without contact-force data, physicians must estimate the amount of force applied to the heart wall during an ablation.

St. Jude’s TactiCath irrigated ablation catheter is designed to give physicians a real-time, objective measure of the force applied to the heart wall. Data that are produced by the TactiCath irrigated ablation catheter is displayed on the EnSite™ Velocity™ System, a cardiac mapping and navigation system via the EnSite™ Contact Force Module. The EnSite Contact software module, which recently received CE Mark approval, seamlessly integrates contact-force ablation technology and 3-D mapping and navigation capabilities.

The starting point for understanding the subject is data from previous studies, including TOCCATA, EFFICAS I and EFFICAS II, which have defined optimal contact-force parameters for the TactiCath catheter as 10 grams(g) of force or more during ablation procedures. The newly reported TOCCASTAR study therefore uses 10g as its threshold.

The TOCCASTAR study is a multicenter, non-inferiority study evaluating 300 patients in the U.S. and Europe. The investigational device exemption (IDE) clinical trial, which followed device performance and assessed patient outcomes through 12 months of follow-up, met its primary safety and effectiveness endpoints. Results demonstrated that the TactiCath™ Irrigated Ablation Catheter exceeded the safety and efficacy non-inferiority benchmarks set forth in the trial by 5.9 percent and 4.3 percent, respectively, based on a 95 percent confidence interval.

Back to the 10g force threshold, results suggest that approximately 75.9 percent of the study patients were free from paroxysmal AF at the end of the 12 month follow-up period, compared to 58.1 percent of patients who did not receive 10g or more of force. 

Investigator comments

“The findings from the TOCCASTAR trial further demonstrate the strong safety and efficacy profile of the TactiCath irrigated ablation catheter for the treatment of atrial fibrillation,” said Dr. Vivek Reddy, director of electrophysiology at Mount Sinai Hospital, N.Y. “The results of this study have significant clinical relevance for optimal cardiac ablation therapy and provide compelling evidence that contact-force ablation procedures are effective in treating paroxysmal atrial fibrillation.”

Company comments

“Results from the TOCCASTAR study represent an important step forward in contact-force ablation technologies,” said Srijoy Mahapatra, M.D., vice president of medical and scientific affairs, global clinical affairs at St. Jude Medical. “We are confident our large and growing body of clinical evidence demonstrates that the use of contact-force ablation safely reduces the rate of AF recurrence and we look forward to making this important technology available to electrophysiologists in the U.S.”

Source: St. Jude Medical, Inc., Business Wire

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