Abstract
Segments of viable human left ventricular trabeculae were obtained at the time of endocardial resection for intractable ventricular ectopy. Muscle segments which showed suitable and reproducible contractions in 26 mM K Tyrode solution with 1 microM isoproterenol were electrically stimulated after rest, and at frequencies of 0.1, 0.25, 0.5, and 1 Hz. Effects of 0.75% halothane and 1.3% isoflurane on peak tension, maximum rate of tension development (dT/dt-max), and on slow (calcium dependent) action potential (AP) characteristics were studied. Halothane depressed peak tension, dT/dt-max, and slow AP maximum rate of depolarization (Vmax) at all frequencies, and caused a significantly greater depression of peak tension and dT/dt-max at 0.5-1 Hz than after rest and at 0.1-0.25 Hz. Isoflurane did not significantly depress slow AP Vmax, showed no frequency dependent contractile depression, and depressed dT/dt-max less than halothane at 0.5 and 1 Hz. Halothane and isoflurane caused differing depression in the pattern of developed tension. The differential depression by halothane and isoflurane of human ventricular myocardium was similar to that previously observed in isolated animal ventricular tissue.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
