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.
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