As early as in the graphical RKG-RCG period a close inverse correlation could be established between the LV-EF and the serum myoglobin level during the acute course of myocardial infarction, in 10 patients in repeated follow up examinations. Corr. coeff. -0.91, p less than 0.01. In the mid seventies it could be shown by RKG-RCG, in 15 IHD patients with angina pectoris that the decrease of the basal LV-EF during ergometric load reflected the severity of IHD, compared with the increasing LV-EF tendency of 15 normal subjects. This fact could be verified on 19 middle age males (mean age, 41 years) by 99mTc RBC gamma camera ventriculography, i.e. that under modest load (100 W ergometry) a more than 10% decrease was a non-specific sign of main branch or three-vessel coronary heart disease. So in this extreme case our nuclear stethoscope-like RKG-RCG method alone may be satisfactory for staging and screening of coronary ischaemic heart disease (IHD) patients. All the 11 normal subjects belonged to the load-reaction group with more than 5% LV-EF increase, while the extensive anterior and inferior scar patients reacted without exception with more than 10% deficit (their basal LV-EF value was already under 45%). Supported by data in the literature in the comparison of load ECG and coronarography and two-step load, we could gain more refined data, but in accordance with the one-step load on the same patients. As regards the reproducibility of our global LV-EF investigations with gamma camera computer program Supersegams, it was within 5%.(ABSTRACT TRUNCATED AT 250 WORDS)