Ablation with a diamond-tip temperature-controlled catheter at 50 W, 60 °C, and 60 s produced significantly larger lesions (mean 569.2 mm3) than shorter or lower-temperature settings (P<0.05).
Does temperature-controlled radiofrequency ablation with a diamond-tip catheter create effective and safe lesions in normal and infarcted ventricular myocardium in a preclinical model?
A novel temperature-controlled diamond-tip radiofrequency catheter safely created large, deep lesions in both normal and infarcted canine ventricular myocardium without steam pops.
Absolute Event Rate: 569.2% vs 340.4%
p-value: p=<0.05
BACKGROUND: Power-controlled radiofrequency ablation with irrigated-tip catheters has been the norm for ventricular ablation for almost 2 decades. New catheter technology has recently integrated more accurate tissue temperature sensing enabling temperature-controlled irrigated ablation. We aimed to investigate the in vivo ablation parameters and lesion formation characteristics in ventricular myocardium using a novel temperature-controlled radiofrequency catheter. METHODS: Twenty canines were divided into 3 groups: 4 noninfarcted, acute (phase I); 8 noninfarcted, chronic (phase II); and 8 infarcted, chronic (phase III). Lesions were delivered with a temperature-controlled radiofrequency system utilizing a chemical vapor deposit diamond for efficient thermal diffusivity. In phase I, 17 ablation settings were tested (temperature set points, 50/60/70 °C; ablation duration, 15/30/60/90/120 s; and power limit, 30/50 W). Four and one of these sets of parameters were further tested in phases II and III, respectively. Lesions were assessed by ex vivo contrast-enhanced magnetic resonance imaging and gross pathology 5 weeks after ablation in phases II/III. RESULTS: Across all phases, 111 ablation lesions were delivered. Ablation with the power limit of 50 W, the temperature set point of 60 °C, and the duration of 60 s produced significantly larger and deeper lesions (mean, 569.2 mm 3 ; mean maximal depth, 9.8 mm) compared with 50 W/60 °C/30 s (mean, 340.4 mm 3 ; mean maximal depth, 8.3 mm) and 50 W/50 °C/60 s (mean, 227 mm 3 ; mean maximal depth, 6.9 mm), with P <0.05 for all pairwise comparisons. Ablation of infarcted myocardium in phase III (50 W/60 °C/30 s) resulted in smaller impedance and bipolar electrogram amplitude changes and lesion size compared with ablation in normal myocardium with the same settings. No steam pop, myocardial perforation, or char formation was observed in any of the 111 ablations across all phases. CONCLUSIONS: In vivo radiofrequency ablation in a canine model with a diamond-tip temperature-controlled catheter using a temperature set point of 60 °C and a power limit of 50 W created large lesions without steam pop risk in both normal and infarcted ventricular myocardia.
Hirao et al. (Fri,) conducted a other in Ventricular ablation (normal and infarcted myocardium) (n=20). Temperature-controlled radiofrequency ablation with a diamond-tip catheter vs. Other ablation settings (e.g., 50 W/60 °C/30 s and 50 W/50 °C/60 s) was evaluated on Lesion volume (mm3) (p=<0.05). Ablation with a diamond-tip temperature-controlled catheter at 50 W, 60 °C, and 60 s produced significantly larger lesions (mean 569.2 mm3) than shorter or lower-temperature settings (P<0.05).