Thirty-five patients including 26 with coronary heart disease and 9 with a pain syndrome non-typical of angina were studied. All patients were subjected to Valsalva's standardized test during which the pressure was measured in the aorta and the heart left ventricle paralleled by simultaneous ECG registration at the three standard leads and at AVR lead. The test sensitivity equalled 50%, the test specificity was 88.9%. Both healthy subjects and coronary heart disease patients displayed a reduction of the diastolic coronary gradient during Valsalva's test, mostly due to the increased diastolic pressure in the left ventricle, which corresponded to the dissemination of coronary atherosclerosis (by coronographic findings). The mechanisms contributing to the development of ischemia associated with Valsalva's test include a fall in coronary perfusion, tachycardia and the reflectory influence of the pulmonary receptors.