Cellular electrophysiological effects of hyperthermia on isolated guinea pig papillary muscle. Implications for catheter ablation.

Nath, Sunil; Lynch, Carl; Whayne, James G.; Haines, David E.

doi:10.1161/01.cir.88.4.1826

Cited by 280 publications

(159 citation statements)

References 11 publications

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“…Previous reports have demonstrated that irreversible electrophysiologic changes to myocytes occur early at 50°C. 26 Because only 1 ablation Ͼ55°C did not result in a transmural lesion, these data suggest that the target tissue temperature at the PV orifice should be 55°C. Furthermore, tissue temperatures remain elevated even after termination of RF energy.…”

Section: Discussionmentioning

confidence: 91%

Analysis of Catheter-Tip (8-mm) and Actual Tissue Temperatures Achieved During Radiofrequency Ablation at the Orifice of the Pulmonary Vein

et al. 2004

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Background-Many ablative approaches in or near the orifice of the pulmonary vein (PV) have demonstrated success in eliminating atrial fibrillation. Despite current practice, there are no data regarding the in vivo efficacy and safety of an 8-mm catheter tip for ablation at the PV orifice. Methods and Results-Ten mongrel dogs were studied. Thermocouples were implanted in the atrial muscle of the PV orifice. Intracardiac echocardiography monitored catheter position, tip/tissue orientation, and microbubble formation. Ninety-four ablations were performed for 120 seconds. A temperature discrepancy Ͼ10°C between the catheter tip and tissue occurred during 47 (50%) of the ablations. Despite termination of energy delivery, the average tissue temperature remained within 1°C of the achieved steady state for 9 seconds. A temperature discrepancy Ͼ10°C was more common in the right superior PV, with oblique catheter positioning, when tissue temperatures were Ͼ60°C or 80°C, and with type 1 or type 2 microbubble formation. However, microbubbles were not present in 7 (13%, type 1) and 10 (40%, type 2) ablations with tissue temperatures Ͼ80°C. The maximum tissue temperature achieved with non-full-thickness lesions was 47.3Ϯ7.4°C vs 75.9Ϯ11.7°C (PϽ0.0001) for full-thickness lesions. Conclusions-Marked discrepancies between catheter-tip and tissue temperatures occurred with higher temperatures, prolonged ablation times, and unfavorable catheter thermistor-tissue contact. Also, these data suggest a conservative approach to atrial ablation, because full-thickness lesions were obtained when tissue temperatures reached 50°C to 60°C and the tissue retained high heat levels despite termination of radiofrequency energy. Finally, microbubbles are inconsistent markers of tissue overheating.

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Section: Discussionmentioning

confidence: 91%

Analysis of Catheter-Tip (8-mm) and Actual Tissue Temperatures Achieved During Radiofrequency Ablation at the Orifice of the Pulmonary Vein

et al. 2004

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“…The mean number of applications of RF energy per patient was 5.9±3.3 (range: [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. There were no complications except for 1 patient with transient AV block.…”

Section: Clinical Resultsmentioning

confidence: 98%

“…5 Haines and Watson reported a temperature range of 46.6-48.9°C in the marginal area between viable and nonviable tissue estimated in vitro using the right ventricle. 6 Hirao et al performed temperature monitoring catheter ablation of the AV junction in dogs and the threshold temperatures at which a transient effect and a permanent effect on AV conduction were observed were 45 and 49°C, respectively.…”

Section: Comparison With Previous Studiesmentioning

confidence: 99%

The Response of the Slow Atrioventricular Nodal Pathway to Temperature

Kawabata¹,

Hirao²,

Toshida³

et al. 1999

Jpn Circ J

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“…16 In this event, T-wave peaking in the endocardial electrogram may have indicated nonlethal injury, with secondary tissue hyperkalemia. 33,34 The most specific repolarization change indicating visible midmyocardial coagulation was ST-segment depression (Figure 4, Table 3). However, electrogram changes were relatively insensitive to the development of intramural coagulation and are not predictive of optical fiber penetration.…”

Section: Discussionmentioning

confidence: 99%

Slow Intramural Heating With Diffused Laser Light

et al. 1999

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Background —Catheter ablation of postinfarction ventricular tachycardia (VT) may be limited by insufficient myocardial coagulation or excessive endocardial or epicardial damage. We propose that volumetric heating restricted to intramural sites may improve the outcome and safety of this procedure, especially if delivered at rates that enhance heat conduction and forestall adverse tissue changes. Methods and Results —A novel optical fiber with a diffusing tip for direct intramural, volumetric laser heating was tested via thoracotomy and percutaneously in normal dogs. Low-power (2.0- to 4.5-W) diode laser light (805 nm) diffused within tissue induced large lesions but no visible surface damage, mural thrombi, or transmural perforation. Mean lesion depth approximated tip length (10 mm). Mean lesion widths in the thoracotomy and percutaneous groups were 5.8±0.5 to 9.1±0.84 mm and 5.2±0.85 to 7.9±1.1 mm, respectively, depending on the light dose. Mean volumes in the percutaneous group were 1006±245 to 2471±934 mm. ST-segment depression, appearing in unfiltered bipolar electrograms recorded from the guiding catheter, was specific for lesion induction. All dogs survived the protocol, which included a 1-hour observation period. In cross section, lesions were elliptical to spherical and characterized by extensive contraction-band necrosis abruptly bordering viable tissue. No platelets or fibrin adhered to the endocardium. Conclusions —Slow, volumetric, and direct intramyocardial heating induces large, deep lesions without hazardous tissue damage. Such heating might cure postinfarction VT more successfully and safely than present techniques. Further testing and development of this method seem warranted.

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Cellular electrophysiological effects of hyperthermia on isolated guinea pig papillary muscle. Implications for catheter ablation.

Cited by 280 publications

References 11 publications

Analysis of Catheter-Tip (8-mm) and Actual Tissue Temperatures Achieved During Radiofrequency Ablation at the Orifice of the Pulmonary Vein

Analysis of Catheter-Tip (8-mm) and Actual Tissue Temperatures Achieved During Radiofrequency Ablation at the Orifice of the Pulmonary Vein

The Response of the Slow Atrioventricular Nodal Pathway to Temperature

Slow Intramural Heating With Diffused Laser Light

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