THORACOTOMY ELEVATES THE DEFIBRILLATION THRESHOLD AND MODIFIES THE DEFIBRILLATION DOSE-RESPONSE CURVE

Citation
Pa. Friedman et Ms. Stanton, THORACOTOMY ELEVATES THE DEFIBRILLATION THRESHOLD AND MODIFIES THE DEFIBRILLATION DOSE-RESPONSE CURVE, Journal of cardiovascular electrophysiology, 8(1), 1997, pp. 68-73
Citations number
16
Categorie Soggetti
Cardiac & Cardiovascular System
ISSN journal
10453873
Volume
8
Issue
1
Year of publication
1997
Pages
68 - 73
Database
ISI
SICI code
1045-3873(1997)8:1<68:TETDTA>2.0.ZU;2-O
Abstract
Thoracotomy Elevates the Defibrillation Threshold. Introduction: Despi te innovations in nonthoracotomy defibrillation systems, thoracotomies are still required in some clinical settings and are utilized in many animal-based research protocols, The effect of a thoracotomy on defib rillation energy, however, has not been well characterized, Methods an d Results: Ten dogs in the immediate testing group underwent defibrill ation testing immediately following a thoracotomy; another ten dogs in the delayed testing group were given 48 to 72 hours of recovery befor e defibrillation testing, A right ventricular endocardial coil to cuta neous thoracic patch biphasic system was used, At the time of defibril lation testing, the immediate testing group had a faster mean heart ra te (144.7 +/- 30.2 vs 105.8 +/- 17.5 beats/min, P < 0.01), higher mean pulmonary artery pressures (systolic: 18.14 +/- 9.18 vs 11.28 +/- 6.4 6 mmHg, P = 0.1; diastolic: 6.59 +/- 2.88 vs 3.89 +/- 1.75 mmHg, P < 0 .05), and higher mean defibrillation shock impedance (89.0 +/- 11.6 vs 70.9 +/- 7.3 Omega, P < 0.002) than the delayed group, The mean ED(50 ) (energy with a 50% success rate) was significantly higher in the imm ediate group than in the delayed group (26.9 +/- 14.9 vs 14.2 +/- 6.9 J, P < 0.05), and the slopes of the dose-response curves were signific antly different (P = 0.03). Conclusion: In a right ventricular endocar dial to cutaneous patch system, thoracotomy significantly and transien tly increased the defibrillation threshold and modified the defibrilla tion dose-response curve.