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[Left ventricular systolic dysfunction in cardiomyopathies]
1Clinique cardiologique et des maladies vasculaires, hôpital Guillaume et René-Laennec, Nantes.
Insights
Dilated cardiomyopathy significantly impairs left ventricular systolic function, leading to enlarged, spherical ventricles and reduced ejection fraction. Contractility indices are severely abnormal and unresponsive to inotropic stimulation.
Area of Science:
- Cardiology
- Physiology
Context:
- Cardiomyopathy encompasses dilated, hypertrophic, and restrictive types.
- Dilated cardiomyopathy is characterized by left ventricular systolic dysfunction.
Purpose:
- To describe the key physiopathological features of dilated cardiomyopathy.
- To highlight the characteristic left ventricular abnormalities in this condition.
Summary:
- Dilated cardiomyopathy involves increased left ventricular volumes, spherical shape, and decreased ejection fraction.
- Wall motion abnormalities, increased ventricular mass with thinning, and prolonged isovolumic contraction time are observed.
- Impaired contractility indices, including maximal velocity of contractile elements, are notably abnormal and do not improve with positive inotropic stimulation.
Impact:
- Provides a detailed understanding of dilated cardiomyopathy's pathophysiology.
- Contributes to the differential diagnosis and management of heart muscle diseases.
Abstract:
Of the three physiopathological types of cardiomyopathy, dilated, hypertrophic and restrictive, it is the first which characteristically shows major left ventricular systolic dysfunction. The left ventricular volumes are increased, the ventricle becomes spherical and global ejection fraction decreases with diffuse or segmental wall motion abnormalities. The left ventricular mass is increased in an excentrical fashion with wall thinning. Isovolumic contraction is slower, the ejection time is shorter and, above all, the indices of contractility such as maximal velocity of the contractile elements ... are very abnormal and do not improve after positive inotropic stimulation.