[Hyperventilation and oxygen supply to the myocardium].

1. Voluntary hyperventilation during rest and in the recumbent position induces a fall in H+ concentration, PCO2 and PO2 in mixed venous blood and in the blood of the coronary sinus. 2. In 7 of 12 patients the arterio-venous O2 difference increased by more than 10% of the control value (mean increase 21%). At the same time the O2 extraction of the myocard increased (mean increase 17%) in these subjects. Blood pressure and pulse rate varied only slightly in these experiments. 3. Chest pain and angina pectoris due to hyperventilation are the result of impaired myocardial O2 supply, a finding which is valid for subjects with and without coronary heart disease.