Handheld radiofrequency probes produced deep linear lesions in the myocardium of dogs, with lesion depth increasing from 3.8 mm at 15 s to 6.1 mm at 120 s at 80 degrees C (P=0.01).
Does varying electrode size, temperature, and duration affect the size and shape of radiofrequency lesions in open-chested dogs?
Handheld radiofrequency probes can create deep, wide linear lesions in the myocardium, with lesion depth increasing significantly with longer ablation duration.
p-value: p=0.01
OBJECTIVES: Detailed analysis of the size and shape of lesions produced by handheld radiofrequency ablation devices at open heart surgery has not been reported previously. METHODS: Radiofrequency lesions were made from the epicardial surface of the cardiac ventricles in open-chested dogs. The effects of electrode size, electrode temperature and duration of ablation were studied. In a second group of experiments simultaneous multielectrode ablation was performed on the ventricular epicardium after cold cardioplegia. RESULTS: Using a single 12 x 2.5 mm electrode and a target temperature of 80 degrees C the lesion depth increased from 3.8+/-0.9 mm at 15 s, to 6.1+/-0.9 mm at 120 s (P=0.01). Increasing the target temperature from 70 to 90 degrees C (for 60 s) increased lesion depth from 5.0+/-1.2 to 5.6+/-1.7 mm (P=0.2). There was no difference in depth of lesions with the two electrode widths (4.0+/-0.5 mm (large) vs. 3.9+/-1.0 mm (small)). Lesions produced using the multielectrode probe (80 degrees C, 60 s) were 30-35 mm long with even penetration into the tissue. The mean depth of these lesions on microscopic sections was 3.9 mm. The mean width was 7.1 mm. CONCLUSIONS: Handheld probes can be used to make deep linear lesions in the myocardium. Lesions expand rapidly and are wider than they are deep. A multielectrode ablation device allows rapid formation of linear lesions.
Thomas et al. (Sat,) conducted a other in Atrial fibrillation surgery (animal model). Handheld radiofrequency ablation devices vs. Different electrode sizes, temperatures, and durations was evaluated on Lesion depth and size (p=0.01). Handheld radiofrequency probes produced deep linear lesions in the myocardium of dogs, with lesion depth increasing from 3.8 mm at 15 s to 6.1 mm at 120 s at 80 degrees C (P=0.01).