抄録
1. The critical or threshold value of the coronary blood flow for the ST-depression was measured in 19 dogs by the bubble flowmeter connected to the cannula inserted into the orifice of the left coronary artery.
2. The normal value was measured as 150 cc./100g. of left ventricle/min. in the open-chest dog anesthetized with pentobarbital under artificial respiration.
3. As the coronary flow reduced, the ST-depression appeared. This critical value of flow was measured as 50-60 cc./100g. of left ventricle/min.
4. The ST-depression disappeared reversibly when the coronary flow was augumented by the intravenous injection of the hypertonics in the hypotonic states.
5. By means of approximate calculation the coronary flow of this level fairly coincides with the lowest value to fulfil the myocardial oxygen demand.
6. From above considerations, the current view, that the reduction of the coronary flow or the defficient oxygen supply for the myocardium is the cause of the ST-depression, is verified directly.
