Cardiovascular Imaging

Cardiomyopathy, dilated

primary disease of the myocardium causing decrease in systolic function and increase in volume of the ventricles. The left ventricle is enlarged with global hypokinesis. The right ventricle is less severely dilated. The aetiology of many dilated cardiomyopathies is unknown. An aetiology may be evident in some such as viral myocarditis, alcohol and other toxins, and ischaemia. Ischaemic cardiomyopathy is now the most frequent type of dilated cardiomyopathy but semantics of classification exclude it from the designation as a cardiomyopathy since the cause is known. Dilated cardiomyopathies have increased left ventricular volumes and reduced ejection fraction. Left ventricular wall thickness is usually normal or slightly reduced but myocardial mass is increased. Regional wall thinning is characteristic of ischaemic cardiomyopathy but can be observed in nonischaemic dilated cardiomyopathy. Mural thrombus occurs in both ischaemic and nonischaemic dilated forms.

Radiography shows cardiomegaly with or without signs of pulmonary venous hypertension or oedema. It is common to have cardiomegaly with no pulmonary venous hypertension. Echocardiography, MRI and left ventriculography demonstrate increased left ventricular end-diastolic and end-systolic volumes and decreased stroke volume and ejection fraction (Fig.1). Global hypokinesis is typical except in ischaemic cardiomyopathy. Mild to moderate mitral regurgitation is frequently identified. Coronary arteriography is frequently done to exclude an ischaemic etiology. PET imaging with fluorodeoxyglucose and ammonia in patients with ischaemic cardiomyopathy is employed to demonstrate a mismatch between perfusion and metabolic defects in the myocardium. A mismatch is a feature of myocardial hibernation for which myocardial revascularization may result in improvement in ejection fraction.

CBH

To view high resolution images,
please register first.

Click  here to register.

Already registered? Enter your e-mail in the window below.
Re-register

Fig.1

End-diastolic (a) and end-systolic (b) cine MR images in the short axis plane show increased dimensions of the left ventricle with little change in size between end diastole and end systole (ejection fraction = 29%).
Cardiomyopathy, dilated, Fig.1 (a)
Cardiomyopathy, dilated, Fig.1 (b)