In an attempt to clarify the relationshop between left ventricular function and chronic obstructive pulmonary disease(COPD), systolic time intervals were measured in 79 control subjects and 60 patients with COPD who had no evidence of organic heart disease. The patients with COPD were divided into three groups based on the percent predicted forced expired volume in one second. Significant differences in pre-ejection period index(PEPI) and left ventricular ejection time index(LVETI) existed between the control subjects and the patients with the most severe lung disease(Group III). A highly significant difference in PEP/LVET existed between these two groups. The abnormalities of systolic time intervals demonstrated in these patients are characteristic of left ventricular dysfunction and indicate that left ventricular dysfunction is frequently present in patients with moderate obstructive lung disease.