Non-invasive measurement of subclavian arterial blood flow as a parameter of cardiac output by the doppler ultrasonic flowmeter.

The subclavian arterial blood flow as a parameter of cardiac output was measured in 7 patients with ischemic heart disease (3 acute myocardial infarction, 3 angina pectoris, 1 variant form of angina pectoris) and 5 normal subjects. The measurement was continuously and non-invasively made, utilizing the Doppler ultrasonic flowmeter technique before, during and after exercise. The exercise was performed in the upright position on a bicycle ergometer for 3 min at the work load of 230Kpm/min. In 3 normal subjects, oxygen consumption at various work loads was also measured by the Douglas bag simultaneously with the subclavian arterial blood flow.In normal subjects, the subclavian arterial blood flow steeply increased soon after the beginning of the exercise and promptly returned to the preexercise level after the termination of the exercise. While in patients with ischemic heart disease, the increase in the subclavian arterial blood flow during the exercise was slow, and the time required to return to the preexercise level was significantly prolonged. Light to moderate exercise under the work load of 230Kpm/min increased both the subclavian arterial blood flow and oxygen consumption nearly in the same ratio. With stronger exercise, the increase in oxygen consumption was by far larger than in the blood flow.Continuous measurement of the subclavian arterial blood flow by the Doppler ultrasonic technique is supposed to be a useful method for the evaluation of cardiac function.