Forty patients with coronary artery disease and 12 normal subjects underwent symptom-limited upright exercise. The pulmonary blood volume was measured by first-pass radionuclide angiography. There was no significant change in pulmonary blood volume during exercise in the normal subjects. Twenty-seven patients (68 percent) with coronary artery disease had an increase in pulmonary blood volume during exercise. Seventeen of the 19 patients (89 percent) with coronary artery disease who stopped the exercise because of shortness of breath had an increase in pulmonary blood volume during exercise compared with ten of 21 patients (48 percent) who stopped because of angina or an abnormal exercise ECG or both (P < 0.02). We concluded that an increase in pulmonary blood volume was seen in 68 percent of our patients with coronary artery disease. The change in pulmonary blood volume was affected by the exercise end-points.
