Abstract 2676: Measured Catheter Tip Temperature Does Not Predict Lesion Depth With Irrigated Radiofrequency Ablation in the Ventricle
Background: Irrigated RF energy is commonly used to treat arrhythmias. Active cooling of the catheter tip allows for greater energy delivery to the myocardium leading to deeper lesions. Nonuniform tip cooling occurs with a standard irrigated RF (StdIRF) catheter. A uniformly cooled irrigated RF (UCIRF) catheter may prevent a catheter tip temp gradient and lead to more consistent energy delivery; however, the impact of uniform cooling on absolute and relative measured tip temp as it relates to lesion creation is unknown.
Methods: We studied two different catheters, a 3.5mm StdIRF and 4.0mm UCIRF, in 12 swine. Up to 4 lesions were placed in the RV and LV of each subject (StdIRF n=46, UCIRF n=46) with the same settings: 25watts, 50deg, 60sec. The animals were sacrificed following the procedure. The hearts were excised, stained, and analyzed at gross necropsy.
Results: Lesion depth was the same for the two catheters. (UCIRF 7.4 +/− 2.6mm vs. StdIRF 7.4 +/− 3.0mm, p=0.94). Measured tip temp was lower for the UCIRF at baseline (28.7 +/−1.3oC vs. 30.0 +/− 1.7oC, p<0.001) and during RF [mean RF temp (30.0 +/− 1.4oC vs. 39.5 +/−3.2oC, p<0.001), max RF temp (31.3 +/− 1.6oC vs.42.0 +/− 3.7oC, p<0.001)]. Relative changes in catheter temperature TempMax-Start (2.9 +/− 1.2oC vs. 12.0 +/− 4.4°C, p<0.001) and TempMean-Start (1.7 +/− 1.1oCvs. 9.5 +/− 4.0oC, p<0.001) were also less with the UCIRF catheter. Neither absolute nor relative changes in measured tip temp correlated with lesion depth. (Graph)
Conclusions: StdIRF and UCIRF tip catheters create similar lesions at the same power settings. Absolute and relative measured catheter tip temp does not predict lesion depth with either catheter tip design.