Assessments of left ventricular function during exercise in patients with dilated cardiomyopathy: comparison with ischemic cardiomyopathy

Responses to supine bicycle ergometer exercise were assessed in a study population consisting of 26 patients with dilated cardiomyopathy (DCM) and 23 patients with ischemic cardiomyopathy (ICM). Left ventricular ejection fraction (LVEF) and regional wall motion were analyzed at rest and during supine bicycle ergometer exercise with radionuclide ventriculography. Although the same degree of LVEF between DCM (23 +/- 8%) and ICM (26 +/- 4%) occurred at rest, the left ventricular regional wall motion abnormality was more prominent in DCM. LVEF during the peak exercise stage in DCM was almost unchanged (24 +/- 8%), but in ICM it decreased significantly (22 +/- 5%). Exercise-induced regional wall motion abnormalities were detected in nine patients (35%) in DCM and 13 patients (57%) in ICM. Although patients with DCM are believed to have diffuse hypokinesis of the left ventricle, severe regional wall motion abnormalities (akinesis or dyskinesis) were frequently observed. During the follow-up period of up to six years, eight patients with DCM died of congestive heart failure. In eight patients with DCM who showed decreased LVEF during exercise, five patients died. However, only three of 18 patients without decreased LVEF during exercise died. Exercise-induced left ventricular dysfunction in DCM seems to be a poor prognostic sign.