Systolic time intervals in chronic obstructive pulmonary disease.

The systolic time intervals (STI) were used to study the left ventricular performance in 51 patients with chronic obstructive pulmonary disease (COPD), in 24 normal subjects and in 13 patients with both COPD and coronary heart disease (CHD). Our study shows that resting spine STI are abnormal in patients with COPD and that the STI in the sitting position and after exercise in these patients are changing in a similar way to those of normal subjects. In patients with both COPD and CHD we found the resting supine STI and the postexercise left ventricular ejection time index (LVETI) to differ from both normals and patients with COPD alone. When these same patients were sitting the STI failed to change, in striking contrast to the normal subjects and to the patients with COPD alone. The similar responses of normal subjects and of patients with COPD in the two stress conditions as well as the different postural and postexercise responses of patients with both COPD and CHD suggest a normal left ventricular function in patients with COPD.