Changes in total and local contractility of the left ventricle, imaged by radionuclide ventriculography, in patients with ischaemic heart disease during submaximal exercise.

In 40 patients with chronic ischaemic heart disease [IHD) and 10 healthy subjects the total and local myocardial contractility was assessed during threshold-level exercise. The patients were subjected to radionuclide ventriculography in a modification recording the first passage of the radioindicator through the heart cavities. In the control subjects the exercise induced a 27% increase in the total ejection fraction, with increased contractility of all left ventricular segments. In the patients with IHD the reactions to exercise varied. In 40% of the patients the total ejection fraction increased adequately, in 17.5% the increase was nonadequate, in 20% no increase was observed, and in 22.5% the ejection fraction decreased. The most marked reduction in myocardial contractility was found in patients who had sustained myocardial infarction and reacted positively to the exercise test. In 34 patients there were observed left ventricular segments showing a paradoxical response of contractility to exercise--a decrease in the local ejection fraction. This pathological local reaction occurred rather in a normal function at rest than in a myocardium with hypokinetic segments at rest.