Abstract
The use of the older methods of studying the isolated heart led to contradictory conclusions regarding the effect of alcohol on cardiac contraction. Sulzer, 1 using the Starling heart-lung preparation, at present the most sensitive and reliable method for this purpose, found no stimulating effect in any concentration and showed that concentrations commonly reached in the human blood stream in alcoholic intoxication produce dilatation without an increase in the work of the heart. We have confirmed this effect and studied the changes in energy metabolism associated with it.
We have used a modified heart-lung preparation, which has been previously described. 2 In some experiments the diastolic volume was allowed to increase when alcohol was added (Table I), while in others (Table II) the external diastolic volume was maintained constant throughout the experiment by adjustment of the venous return. In all cases the venous pressure had to be lowered in order to keep diastolic volume constant after alcohol. A piston recorder was used for ventricular volume recording and the heart was held in a glass cardiometer, following the technique of Starling and Visscher. 3
After a control period of 15 to 30 minutes, during which the volume output and oxygen usage remained constant, the desired amount of alcohol was injected into the tubing between the stromuhr and the venous reservoir so as to insure thorough mixing before reaching the heart. Within 30 to 40 minutes after the injection the variables recorded had generally reached a new fairly constant level, and then in some experiments alcohol was injected again and the effect of the higher concentration determined. The concentration of alcohol injected was 20% except in Exp. 4/10/33, in which 95% alcohol was added to the blood undiluted for purposes of comparison. The time of injection was generally 2 to 3 minutes.
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