Effects of procaine on hypoxia induced abnormalities in canine myocardial tissues

Combined effects of hypoxia, hyperkalemia and acidosis (HH&A) produced contracture (increased resting tension) in canine ventricular muscle tissues but not in Purkinje fibers perfused for the same length of time. Administration of procaine during such contracture stabilized the resting tension somewhat. High [Ca]o during HH&A causes contracture to appear much sooner. On return to oxygenated tyrode oscillatory after potentials (or oscillations in diastole) developed in ventricular muscles, and these oscillations disappeared in the presence of procaine.