Quantitative radiocardiographic evaluation of cardiac dynamics in man at rest and during exercise

113Inm radiocardiography in conjunction with a gamma camera and a digital computer is applied to measurements of cardiac output, stroke volume, ejection fraction, end-diastolic volume, pulmonary blood volume, pulmonary transfer time and dispersion both at rest and during muscular exercise. A modified gamma function is used in calculations of radiocardiographic curves. In twelve supine male subjects the maximal increase of cardiac output was 220%, stroke volume 30%, ejection fraction 15%, and pulmonary blood volume 30%. The present method provides a non-invasive tool for cardiovascular examinations during exercise.