An echocardiographic follow-up study was performed in 59 patients with dilated cardiomyopathy to characterize the relationship between left ventricular systolic dysfunction and the myocardial tissue character assessed by echocardiographic myocardial gray level distributions. All the selected patients were divided into two groups; those with (group A) and those without (group B) progressive systolic dysfunction. In group A, the ejection fraction decreased from 47 +/- 5 to 23 +/- 4% (p < 0.05) during the follow-up period. The histogram of the myocardial gray level distribution became wider, less peaked and more right-sided in those patients. The relative echo intensity of the myocardium increased from 1.29 +/- 0.19 to 1.60 +/- 0.18 (p < 0.01). In group B, however, neither the shape of the gray level distribution nor ejection fraction changed during the same follow-up period. The relative echo intensity did also not change. Our present results suggested that some of the patients with dilated cardiomyopathy showed progressive systolic dysfunction with extensive myocardial tissue damage.