Figure 1. (Top) Concentration-response curves for the effect of halothane (0-4%) on isometric force of contraction in isolated, electrically driven ventricular strips (1 Hz) from patients who underwent heart transplantation and from nonfailing healthy donor hearts. Experiments on eight preparations from six failing hearts and seven preparations from five nonfailing hearts were carried out. (Middle) Original recording of the effects of halothane (2%) and isoproterenol (0.1 micro mol/l) on the force of contraction in an isolated, electrically driven ventricular preparation from a patient who underwent heart transplantation. (Bottom) Original recording of the effects of halothane (2%) and ouabain (0.02 micro mol/l) on the force of contraction in an isolated electrically driven ventricular preparation from a patient who underwent heart transplantation.