title: Temperature-controlled cooled-tip radiofrequency ablation in left ventricular myocardium.
abstract: Steam pop and intramural charring have been reported during cooled-tip radiofrequency catheter ablation (RFCA). We studied the feasibility of temperature-controlled cooled-tip RFCA in the canine heart.An internally cooled ablation catheter was inserted into the left ventricle. A custom-made radiofrequency (RF) generator capable of controlling the tip-temperature at the preset level by slow increases in the power was used. Temperature-controlled cooled-tip RF applications were performed at a target temperature of 40 degrees C for 90 seconds. Acute study: Intramyocardial temperature was measured at the ablation site in 10 dogs by inserting a fluoroptic probe. Chronic study: Lesion depth and volume were measured in 5 dogs after 3 weeks of survival. In the acute study, no pop or abrupt impedance rise was observed. Maximum intramyocardial temperature was 72.4 + or - 14.4 degrees C at 2-4 mm above the endocardium. No coagulum formation, craters, or intramural charring were observed. Maximum lesion depth was 6.7 + or - 1.5 mm, and lesion volume was 404 + or - 219 mm3. In the chronic study, maximum lesion depth was 5.9 + or - 1.1 mm, and lesion volume was 281 + or - 210 mm(3).Temperature controlled RFCA is feasible with a cooled-tip catheter and an RF generator that slowly increases the RF power until the preset catheter-tip temperature is reached.
authors.affiliation: Division of Cardiology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-kami, Itabashi-ku, Tokyo 173-8610, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Watanabe
authors.forename: Min
authors.initials: M
authors.lastname: Nuo
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Okumura
authors.forename: Kimie
authors.initials: K
authors.lastname: Ohkubo
authors.forename: Sonoko
authors.initials: S
authors.lastname: Ashino
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kofune
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kofune
authors.forename: Toshiko
authors.initials: T
authors.lastname: Nakai
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kasamaki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hirayama
mesh_terms: D000465:Algorithms; D000818:Animals; D002058:Burns, Electric / Q000209:etiology* / Q000473:pathology / Q000517:prevention & control*; D017115:Catheter Ablation / Q000009:adverse effects* / Q000295:instrumentation*; D003080:Cold Temperature; D004285:Dogs; D004699:Endocardium / Q000293:injuries; D004867:Equipment Design; D006335:Heart Injuries / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D006352:Heart Ventricles / Q000293:injuries; D023421:Models, Animal; D015203:Reproducibility of Results; D013814:Thermal Conductivity