The sodium and potassium content of normal human hearts

ABSTRACT

Forty-four hearts, showing no signs of hypertrophy or disease, were selected from persons dying suddenly from accidental, suicidal or homicidal causesSamples from each heart were obtained from the right ventricle and from the epicardium (outermost 1-2 mm. portion) and endocardium of the left ventricle. These samples were analyzed for sodium and potassium by flame photometry, after being freed of all removable fat and blood vessels. The results were expressed in mEq 100 Gm. of fat-free and water-free tissueThe left ventricle had significantly (15 per cent) more potassium than the right; while the right ventricle had significantly (30 per cent) more sodium than the left. The left ventricular epicardium had significantly more sodium than the endocardium, but an equal concentration of potassiumThe higher sodium concentration in the outer ventricular layer (epicardium) was interpreted to mean that this area probably had relatively more extracellular fluid as a result of the squeezing action of the intramyocardial pressureThe higher sodium content of the right ventricle was thought to be due only partly to a greater amount of extracellular space. The possibility that some of this sodium in the right ventricle must be intracellular could not be eliminated because of the lower potassium content of this ventricle and the previous studies demonstrating a reciprocal relationship between these ionsThe difference in potassium content between left and right ventricles was considered to indicate a difference in the potassium of the muscle cells themselves, and consequently, as a reflection of differences in cellular metabolism and activity. Some physiologic qualities of the normal right ventricle that differ from the left ventricle were cited as possible effects of these cellular chemical differences. (Summary)