Radionuclide methods for cardiac output determination.

For repeated determinations of cardiac output, radionuclides have provided a safe, reliable and minimally invasive approach. The techniques used are (1) the first-pass dilution method and (2) the derivation of stroke volume from end-diastolic and end-systolic ventricular volumes. Each of the two techniques offers specific advantages, thus, both may be used clinically according to the type of evaluation that is required. Their development has been helped by the availability of adequate radiopharmaceuticals as well as highly efficient precordial detection devices, computer systems, and data handling 'software'. The associated patient exposure to radioactivity has not precluded clinical application because of the small doses used and the protective measures applied.