Temperature-guided radiofrequency catheter ablation of closed-chest ventricular myocardium with a novel thermistor-tipped catheter

• Published in: The American heart journal Vol. 127; no. 6; pp. 1614 - 1618
• Main Authors: Pires, Luis A., Huang, Shoei K.Stephen, Wagshal, Alan B., Mittleman, Robert S., Rittman, William J.
• Format: Journal Article
• Language: English
• Published: New York, NY Mosby, Inc 01.06.1994; Elsevier
• Subjects: Analysis of Variance; Animals; Biological and medical sciences; Catheter Ablation - instrumentation; Catheter Ablation - methods; Catheter Ablation - statistics & numerical data; Diseases of the cardiovascular system; Dogs; Electrocardiography; Equipment Design; Feasibility Studies; Heart Ventricles - surgery; Medical sciences; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Semiconductors; Temperature; Heart; Thermistor; Fissipedia; Carnivora; Temperature; Instrumentation therapy; Catheter; Radiofrequency; Ablation; Guidance; Vertebrata; Mammalia; Animal; Dog
• ISSN: 0002-8703; 1097-6744
• DOI: 10.1016/0002-8703(94)90394-8

Successful lesion formation using radiofrequency energy requires adequate tissue heating. Temperature monitoring during ablation may thus improve the efficiency of radiofrequency catheter ablation. Each of five anesthetized, closed-chest adult mongrel dogs weighing 19 to 24 kg received a single pulsed ablation at four left ventricular and two right ventricular sites using a thermistor-tipped 2 mm electrode catheter. The maximum temperature at the electrode-tissue interface was preset at 90° C and current delivered for 40 seconds (method A) or at 70° C for 40 seconds (method B 1) or 80 seconds (method B 2). With method C, the temperature was set at 90° C for 20 seconds, after which the temperature setting was turned off and ablation continued until impedance increased or the temperature reached ≥ 100° C. The size of the resultant lesion was greater with method A than with methods B 1, B 2 or C (mean length × width × depth, 5.6 × 4.8 × 6.5 vs 4.1 × 4.0 × 5.1 vs 4.2 × 4.0 × 5.2 vs 5.0 × 4.3 × 5.7 mm, respectively; p < 0.01). There was no significant difference in lesion size between pulse durations of 40 seconds (group B 1) and 80 seconds (group B 2). Only two ablations, both in the anteroapical right ventricle, resulted in a marked rise in impedance without the temperature reaching ≥ 100° C. We conclude that temperature (and thus impedance) monitoring improves control and efficacy of lesion formation during radiofrequency catheter ablation.