Restrictive cardiomyopathy is defined as heart-muscle disease that results in impaired ventricular filling, with normal or decreased diastolic volume of either or both ventricles. Systolic function usually remains normal, at least early in the disease, and wall thickness may be normal or increased, depending on the underlying cause.¹ The condition usually results from increased stiffness of the myocardium that causes pressure within the ventricle (or ventricles) to rise precipitously with only small increases in volume. Since the condition affects either or both ventricles, it may cause symptoms and signs of right or left ventricular failure. Often, right-sided findings predominate, with . . .