THE EFFECT OF ANOXEMIA ON THE SIZE OF THE HEART AS STUDIED BY THE X-RAY

Abstract

The normal cardiac area was ascertained by taking x-ray pictures and measuring the cardiac silhouette with a planimeter. The animals were placed in a steel chamber and subjected to atmospheric pressures corresponding to 2.5-8.3% O. About 8 min. were allowed to bring the animals to the desired level and the barometric pressure was held at this point for 2 min. The animals were then removed and the cardiac area was again determined. In another series, x-ray pictures were taken during the anoxemia. The animals all showed an increase in cardiac area varying from 7.7 to 18.85%, depending on the degree of anoxemia. The greater the degree of anoxemia, the greater the cardiac dilatation[long dash]up to a definite maximum. Some animals showed a cardiac dilatation at a less reduction in O % than others.