[Myocardiopathies (XI). Restrictive myocardiopathy: concept, classification, and clinical approach].

Currently, cardiomyopathies are defined as "heart muscle diseases of unknown etiology". Restrictive cardiomyopathy is the rarest type of this disease, and the only one with no uniformly accepted diagnostic criteria. Its importance lies primarily in properly distinguishing it from constrictive pericarditis because of the direct consequences of mistakenly treating a case of constrictive pericarditis as if it were inoperable. Restrictive cardiomyopathy must be considered within the broader spectrum of diastolic dysfunction. Diagnostic criteria used show a general consensus for the diagnosis of restrictive cardiomyopathy in patients with clinical signs of heart failure in the presence of a nondilated, nonhypertrophic left ventricle with preserved contractility but abnormal diastolic function. Characteristically, right and left ventricular filling pressures are elevated and a dip and plateau diastolic pressure pattern appears. Restrictive cardiomyopathy may be either idiopathic and thus be a true cardiomyopathy in the strict sense of the term or secondary to an infiltrative disease of the myocardium. In this article we review the clinical and hemodynamic features of this disease and the different imaging techniques used in patients to help differentiate restrictive cardiomyopathy from constrictive pericarditis. Finally we study some types of restrictive cardiomyopathies.