Echocardiography in adult cardiomyopathy.

Echocardiography allows distinction between the diastolic dysfunction of hy pertrophic or restrictive cardiomyopathies and the systolic dysfunction of dilated cardiomyopathy. The diagnosis and prognosis may be deduced from ech ocardiographic parameters. In hypertrophic cardiomyopathy systolic function is normal and there is asymmetric left ventricular hypertrophy (> 13 mm) a ssociated with a reduced diastolic dimension and atrial dilatation resultin g from diastolic dysfunction. The prognosis could be related to the severit y of left ventricular hypertrophy; right ventricular hypertrophy is uncommo n and its severity seems to be related to that of left ventricular hypertro phy. Restrictive cardiomyopathies are less common and amyloidosis is the co mmonest cause. Symmetric hypertrophy with reduced diastolic dimensions is o bserved; right ventricular involvement occurs in about 30% of cases. The pr ognosis seems to be related to the degree of parietal infiltration and, at advanced stages, systolic function is abnormal (fractional shortening < 20 % with a left ventricular diastolic dimension greater than or equal to 55 m m) and rapidly fatal. Dilated cardiomyopathy is diagnosed when wall thickne ss is normal but left ventricular diastolic dimensions > 27 mm/m(2) and eje ction fraction < 45 %. Right and left ventricular dimensions of the same si ze, left ventricular diastolic dimensions > 70 mm and left ventricular ejec tion fractions < 20 % are poor prognostic indicators.