Temperature-Controlled Irrigated RF Ablation
What are the preclinical and clinical performances of a novel irrigated radiofrequency (RF) catheter with a diamond-embedded tip (for rapid cooling) and six surface thermocouples for pulmonary vein (PV) isolation?
The TRAC-AF (ACT DiamondTemp Temperature-Controlled and Contact Sensing RF Ablation Clinical Trial for Atrial Fibrillation) investigators used the DiamondTemp (DT) catheter on pigs (n = 6) for discrete atrial ablation in a temperature control mode (60°C/50 W) until there was ~80% electrogram amplitude reduction. In a single-center clinical feasibility study, 35 patients underwent PV isolation with the DT catheter (study group); patients were planned for PV remapping after 3 months, regardless of symptomatology. A control group included 35 patients who underwent PV isolation with a standard force-sensing catheter. Chi-square tests were used to compare the categorical variables, and the two-sample Student t-test was used to compare normally distributed continuous variables. The Mann-Whitney U test was used to compare the continuous variables that were not normally distributed.
Porcine lesion histology revealed transmurality in 51 of 55 lesions (92.7%). In the patients, all PVs were successfully isolated; no char or thrombus formation was observed. Compared with the control group, the study cohort had shorter mean RF application duration (26.3 ± 5.2 minutes vs. 89.2 ± 27.2 minutes; p < 0.001), shorter mean fluoroscopic time (11.2 ± 8.5 minutes vs. 19.5 ± 6.8 minutes; p < 0.001), and lower acute dormant PV reconduction (0 of 35 vs. 5 of 35; p = 0.024). At 3 months, 23 patients underwent remapping: 39 of 46 PV pairs (84.8%) remained durably isolated in 17 of these patients (73.9%).
The authors concluded that this first-in-human series demonstrated that temperature-controlled irrigated ablation produced rapid, efficient, and durable PV isolation.
This combination of preclinical and nonrandomized pilot clinical data suggests that catheter tip-surface thermocouples appear to permit safe and effective temperature-controlled, saline-irrigated RF ablation. Using this power titration strategy, the first-in-human TRAC-AF clinical series demonstrated that rapid and durable PV isolation was potentially achievable. Additional experience with this catheter in multicenter studies is indicated to accurately determine its efficacy and safety profile.
Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Catheter Ablation, Electrophysiologic Techniques, Cardiac, Fluoroscopy, Pulmonary Veins, Thrombosis
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