title: Radio-frequency ablation: effect of voltage and pulse duration on canine myocardium.
abstract: The purpose of this investigation was to examine in vivo the relationship of radio-frequency (RF) pulse voltage and duration on the volume of tissue injury. RF 500-kHz pulses of 20-, 40-, and 60-V amplitude (RMS) were applied to the epicardium of 18 dogs for pulsing periods of 5-20 s. Systematic and quantitative tissue analysis was then performed after 30 days. No chronic lesions were evident on microscopic examination for 20-V RF pulse applications up to 15 s. Application of 20-V pulses for 20 s produced small lesions having a volume of 2.4 +/- 0.7 mm3. At 40 V, the volume of tissue injury ranged from 39.1 +/- 10.3 mm3 for 5 s of pulse application to 128.8 +/- 24.8 mm3 for 20 s of pulse application. Over the first 15 s of 40-V pulse application, the volume of tissue injury increased as pulse application time increased. There was no further increase in tissue injury for 40-V pulsing durations greater than 15 s. At 60 V, volumes of tissue injury ranged from 122.7 +/- 33.5 mm3 at 5 s to 313.6 +/- 73.7 mm3 at 20 s. Lesion size increased significantly for pulse durations of up to 10 s. Thereafter, 60-V pulses yielded little increase in tissue injury. In addition, persistent 60-V pulsing for periods greater than 9 s duration resulted in arcing and tissue vaporization in 28% of the applications. Thus RF energy is limited in its ability to create safe and effective tissue injury.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, University of Washington, Seattle 98195.
authors.forename: G H
authors.initials: GH
authors.lastname: Bardy
authors.forename: P L
authors.initials: PL
authors.lastname: Sawyer
authors.forename: G W
authors.initials: GW
authors.lastname: Johnson
authors.forename: D D
authors.initials: DD
authors.lastname: Reichenbach
mesh_terms: D000818:Animals; D004285:Dogs; D004560:Electricity; D004864:Equipment and Supplies; D006321:Heart / Q000528:radiation effects*; D009206:Myocardium / Q000473:pathology; D011846:Radio Waves; D013997:Time Factors