The relationship between coronary flow reserve and the result of coronarography was examined. 152 patients were investigated by stress transoesophageal echocardiography and coronary angiography. The value of coronary flow reserve was significantly lower in cases of significant coronary stenosis than in those patients who had a normal coronarography (in patients with left anterior descending coronary artery stenosis: 1.77 +/- 0.47 vs in cases with normal coronary angiogram: 3.19 +/- 1.15). There was no difference in the value of CFR in those cases where not only LAD stenosis but CX or RC stenosis was also found. The value of coronary flow reserve was significantly higher in RC or CX patients than that of LAD patients. In patients with positive stress and negative coronarography (X syndrome) the coronary flow reserve was 1.23 +/- 0.2, which value was significantly lower as compared to patients with significant coronary stenosis.