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Large Radiofrequency Ablation Lesions Can Be Created with a Retractable Infusion‐Needle Catheter
Author(s) -
SAPP JOHN L.,
COOPER JOSHUA M.,
ZEI PAUL,
STEVENSON WILLIAM G.
Publication year - 2006
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.2006.00439.x
Subject(s) - medicine , saline , ablation , catheter , endocardium , radiofrequency ablation , catheter ablation , ventricular tachycardia , ventricle , coagulative necrosis , nuclear medicine , surgery , anesthesia , cardiology
Background: Radiofrequency (RF) catheter ablation of ventricular tachycardia is sometimes limited by inadequate lesion depth. We report the use of a novel retractable needle‐tipped electrode catheter with intramyocardial (IM) saline infusion and IM RF energy delivery to create large myocardial ablation lesions. Methods: The left ventricle was entered via the femoral artery in 6 and 11 anesthetized goats and swine (32–90 kg) with an 8‐F electrode catheter with an extendable 27‐gauge needle at the tip (modified for RF ablation by making the needle electrically active). The needle was advanced 5–7 mm intramyocardially and 0.9% saline was infused 1 mL/min × 60 seconds prior to, and throughout a 120‐second application of RF via the active needle, with power titrated to 12 W for 9 lesions, and 30–40 W for 37 lesions, followed by a 120‐second RF application using the 4‐mm‐tip electrode, with power titrated to achieve a 10‐Ω decrease in impedance. Needle/saline lesions were compared to 18 standard 4‐mm‐tip control lesions (power titrated to ≤50 W, to achieve a 10‐Ω impedance decrease or limited to 60°C) and to 17 irrigated 3.5‐mm‐tip lesions (power titrated to ≤50 W, temperature limited to 50°C, 30 mL/min infusion rate). Lesions were identified in the excised heart, fixed, serially sectioned from the endocardium, and digitally analyzed to calculate volume. Results: Lesions were homogeneous and had distinct borders. Compared to 4‐mm‐tip and irrigated‐tip lesions, high‐power needle/saline lesions were significantly deeper (13 ± 2 vs 5 ± 1 and 8 ± 3 mm, P < 0.001), had significantly larger volumes (1,700 ± 750 vs 240 ± 170 and 750 ± 650 mm 3 , P < 0.001), and had larger cross‐sectional area at each millimeter depth beyond the 1 mm (P < 0.01). Conclusions: IM saline infusion and IM RF energy delivery markedly increase RF lesion size as compared to standard RF ablation and is feasible with a percutaneous catheter. This method warrants further investigation because of its potential clinical utility.