The Influence of Poly vinyl Chloride (P.V. C.) Tubing on the Isolated Perfused Rat's Heart

In 20 consecutive perfused heart experiments, the electrocardiograms and inductocardiograms of the isolated heart were found unchanged for periods of 4 hours or more. Subsequent expansion of our laboratory facilities made it necessary to rebuild our perfusion apparatus. After this, over 50 successive perfusions proved to be unsuccessful. Premature cardiac arrest and ventricular fibrillation occurred. Calcium, epinephrine, strophanthin and aminophylline, added to the perfusion fluid, were ineffective in combating the deterioration. A thorough investigation of the perfusion fluid did not reveal any change in chemical composition. Perfusion pressure was constant throughout all experiments. It seemed possible, therefore, that the polyviny] chloride tubing which had been used instead of the glass tubing in the original set-up could be the responsible factor."" Experiments were therefore designed to test this possibility.