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Assessments of left ventricular function during exercise in patients with dilated cardiomyopathy: comparison with
1First Department of Internal Medicine, Mie University School of Medicine, Tsu.
Insights
Exercise-induced left ventricular dysfunction in dilated cardiomyopathy (DCM) is a poor prognostic sign. Patients with DCM showed unchanged ejection fraction during exercise, unlike those with ischemic cardiomyopathy (ICM).
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Exercise Physiology
Background:
- Dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) are leading causes of heart failure.
- Understanding the functional response to exercise is crucial for prognosis in these conditions.
Purpose of the Study:
- To compare the effects of supine bicycle ergometer exercise on left ventricular function in patients with DCM and ICM.
- To determine if exercise-induced left ventricular dysfunction is a predictor of poor outcomes in DCM.
Main Methods:
- 26 patients with DCM and 23 with ICM underwent radionuclide ventriculography at rest and during peak exercise.
- Left ventricular ejection fraction (LVEF) and regional wall motion were assessed.
- Follow-up data up to six years were collected to assess mortality.
Main Results:
- At rest, LVEF was similar between DCM (23%) and ICM (26%), but regional wall motion abnormalities were more prominent in DCM.
- During peak exercise, LVEF remained unchanged in DCM (24%) but decreased in ICM (22%).
- Exercise-induced regional wall motion abnormalities occurred in 35% of DCM patients and 57% of ICM patients.
- In DCM patients, decreased LVEF during exercise was associated with a higher mortality rate (5/8) compared to those without decreased LVEF (3/18).
Conclusions:
- Exercise-induced left ventricular dysfunction, characterized by a decrease in LVEF during exertion, is a significant indicator of poor prognosis in patients with dilated cardiomyopathy.
- Despite assumptions of diffuse hypokinesis, severe regional wall motion abnormalities are frequently observed in DCM patients during exercise.
- Further research is warranted to explore the mechanisms and therapeutic implications of exercise-induced ventricular dysfunction in DCM.
Abstract:
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.