Abstract 9867: Insulating an Open Irrigated Ablation Electrode Improves Electrode Temperature Feedback for Radiofrequency Lesion Formation and Steam Pop
Introduction: Open irrigation (Irg) cools electrode and electrode-tissue interface (ETI), and prevents thrombus while producing large RF lesions. However, electrode temperature (ET) does not predict excessive tissue heating and steam pop. The purpose of this study was to compare the relationship of ET to lesion size and steam pop between a novel thermally insulated Irg electrode (Gen2, St Jude Medical) and a conventional, non-insulated 4 mm Irg electrode (St Jude Medical) using a canine thigh muscle preparation.
Methods: In 4 dogs, the skin over the thigh muscle was incised and raised to form a cradle, which was superfused with heparinized blood at 37°C. 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). Gen2 and a conventional 7F, 4mm Irg catheter were held perpendicular or parallel to thigh muscle. Catheter-tissue contact force was applied at 5, 20 or 40 g. RF was applied for 60 sec at 20 W for Gen2 (Irg 17 ml/min) and 40 W for the 4mm electrode (Irg 17 ml/min). ET, ETI, and tissue temperatures (3 and 7mm depths) were measured. Dogs were sacrificed at 2 hours after ablation and lesion size was measured.
Results: Table and Fig.
Conclusions: Gen2 had a wider range of peak ET than 4 mm. Gen2 had better correlation between peak ET and lesion depth (R=0.71 vs. R=0.26), and between peak ET and steam pop (ET>54°C vs. ET >34°C).
- © 2011 by American Heart Association, Inc.