The possible relationship between cardiac glycogen levels, ouabain toxicity and the anti-arrhythmic effect of anacardium occidentale

ABSTRACT

Using the open chest dog with the heart in situ, the influences upon the cardiac glycogen by fasting, anacardium occidentale, and ouabain were studied. Fasting elevated the cardiac glycogen while intravenous infusion of glucose did not increase the cardiac glycogen. Anacardium occidentale elevated the cardiac glycogen after a slow intravenous infusion. The depletion of cardiac glycogen occurred concurrently with the onset of ectopic beats due to ouabain toxicity, and the toxic dose of ouabain was significantly increased in relation to the high cardiac glycogen. The stress of cardiac surgery significantly depleted the glycogen content of the human heart, and this depletion was not related to trauma or the time the patient was on cardio-pulmonary by-pass. It is concluded that (a) anacardium occidentale protects against ouabain arrhythmias by elevating the cardiac glycogen, (b) there is a critical cardiac glycogen level below which ouabain readily becomes toxic, and (c) surgery on the heart in the human depletes its glycogen stores (AU)