Abstract 14075: Thermal Insulation for Saline Irrigated Radiofrequency Ablation Electrode Allows Electrode Temperature Feedback for Lesion Formation
Saline irrigation (Irg) cools electrode-tissue interface (ETI) and prevents thrombus while producing larger RF lesions. However, Irg also cools the electrode, compromising the use of electrode temperature (ET) in assessing lesion formation. To improve ET feedback, a novel thermally insulated 2.5 mm Irg electrode was developed (Gen2, St Jude Medical). The purpose of this study was to compare ET rise and lesion size (during both a brief low power test RF and during RF ablation) between the Gen2 and a non-insulated 4 mm Irg electrode (Therapy Cool FlexTM catheter, St Jude Medical, CF).
Methods: Gen2 has a 7F, 2.5 mm tip electrode with 6 proximal and 1 distal thermally insulated Irg channels to provide only external electrode cooling (Fig A). Five dogs were studied closed chest. Gen2 and CF were positioned in RV and LV under fluoroscopy. The relationship between ET increase and lesion depth was compared between Gen2 and CF during: 1) pre-ablation test RF pulse (5 W, 5 sec, 2 ml/min saline Irg); 2) ablation at 3-4 separate sites each in RV and LV (Gen2 - 15 W in RV, 25 W in LV for 60 sec, 17 ml/min Irg; CF - 30W in RV, 50W in LV for 60 sec, 17 ml/min Irg). Dogs were sacrificed at 1 hour after ablation and lesion size was measured.
Results: Figs B-E. Lesion depth correlated well with increase in ET for test RF and during ablation for Gen2. The increase in ET was small for CF, and did not correlate with lesion depth during the test RF. In addition, the increase in ET during ablation correlated poorly with lesion depth for CF. Gen2 required 50% less power to create equally large lesions as CF.
Conclusions: ET feedback is markedly improved in the thermally insulated Gen2. Test RF before ablation with Gen2 predicts lesion size.
- © 2011 by American Heart Association, Inc.