PO-02-076 AN INVESTIGATION OF LESION EFFICACY AND SAFETY WITH THE TACTIFLEX™ SE ABLATION CATHETER

Abstract

Treatment of cardiac arrhythmias by the creation of myocardial lesions utilizing RF current is well established as an effective mode of therapy in the clinical electrophysiology laboratory. Efficacy, however, should be evaluated in concert with safety considerations, as passive resistance in the cardiac tissue creates heating that can lead to adverse events (e.g., steam pops). A bench top bovine tissue model allows for comparative testing of RF ablation with the TactiFlex™ SE Ablation Catheter (test device) and a commercially available solid-tip RF ablation catheter with uniform irrigation profile (control device), analyzed with respect to both efficacy and safety. To generate comparative statistics for lesion dimension (maximum width and depth) and steam pop likelihood for the TactiFlex™ SE and control RF catheter designs. In this bench ablation model, recently harvested bovine ventricles were sectioned and placed in a body-temperature saline solution (∼37oC). A catheter in a holding fixture was placed in contact with the tissue at a predefined contact force using an independent force gauge. RF energy was applied to the tissue; lesions (N=288 trials) were created at three different power levels (30W at 30s or 50s, 40W at 12s or 20s, 50W at 6s and 10s), steam pop occurrences were noted. Applied contact force levels were fixed at either 5g or 20g. After ablation, the tissue was stained with 1% Triphenyltetrazolium chloride (TTC). Lesions were measured with respect to maximum width and depth. A linear regression model was applied for lesion width and depth vs. catheter design, power, duration, contact force and orientation. The trials did not result in significantly different widths between catheter designs (p = 0.137); refer to Figure 1 for dimensions vs. RF power and duration. Trials with the TactiFlex™ SE yielded shallower lesions (p=0.018) compared to the control device, but with a regression bias of only 0.2mm. Logistic regression demonstrated that steam pops were significantly less likely with the TactiFlex™ SE (p=0.002). Steam pops occurred in only 1.4% of trials with the TactiFlex™ SE Ablation Catheter (2/144 trials) versus 9.7% of trials with the control catheter design (14/144 trials). RF lesions can be created with the TactiFlex™ SE Ablation Catheter that are clinically similar in size to those created with the control device, with a significant reduction in steam pop likelihood.