The assessment of left ventricular ejection fraction in patients with ischaemic heart disease by contrast ventriculography and nuclear angiography.

1. In 18 patients with ischaemic heart disease left ventricular ejection fraction, measured by two different nuclear angiographic methods, has been compared with ejection fraction measured by single-plane contrast angiography. 2. The first nuclear angiographic technique involves detection of variation in the radio-activity from the left ventricle during the initial passage of a bolus of 99Tcm-labelled human serum albumin injected intravenously; the second is our own modification of a "gated" method, which accumulates the radioactivity detected during the continuing recirculation of the plasma bound radioisotope, so presenting an "averaged" ventricular volume curve. 3. Ejection fraction, measured by the "bolus" method, is lower than that measured either by contrast ventriculography or by the "gated" method. This may be due to a damping effect. 4. Ejection fraction measured by the "gated" method is well correlated with that measured by contrast ventriculography (r = 0-89). 5. Our modification of the "gated" method, which presents the changes in ventricular volume throughout the cardiac cycle, without needing computer facilities, is a useful non-invasive means for assessment of left ventricular function.