Our study population consisted of three groups: 1. 24 cases with ejection fraction (EF) > 45% in 26 patients with angina decubitus (AD) were studied as group A. 2. 20 patients had coronary artery disease without AD as group B. Group B and A were matched for age, EF and coronary artery obstructive lesions. 3. 20 cases without cardiovascular diseases as group C. Left ventriculography (LVG) was performed in these patients. The results showed that left ventricular (LV) early 1/3 filling fraction (1/3FF) was significantly reduced in group A as compared with that in group B and C (both P < 0.001). The findings suggest that patients with AD have abnormalities of LV diastolic filling. Left ventricular end diastolic pressure (LVEDP) significantly increased in patients with AD after LVG as compared with before LVG (P < 0.01). However, there was no statistically difference in LVEDP before and after LVG in both group B and C, indicating that the compliance of LV was also decreased in patients with AD. The increase of LV volume after recumbency would cause increase of LV wall tension and myocardial contraction and aggravate the LV diastolic dysfunction, resulting in a progressive increase in myocardial oxygen consumption. Therefore, we consider that on the basis of severe coronary artery obstructive lesions, LV diastolic dysfunction is a significant pathologic factor in the pathogenesis of AD.