Myocarditis and Dilated Cardiomyopathy

This chapter reviews the evidence linking autoimmunity with two important forms of heart disease, myocarditis and dilated cardiomyopathy. It must be stated that immunologic testing has so far not been effective in allowing a clear distinction between autoimmune and other etiologies of these diseases. The major features of myocarditis include arrhythmias, embolic events, congestive heart failure, or cardiogenic shock. These clinical findings can be supported by electrocardiographic changes, such as nonspecific ST-T wave abnormalities and atrial or ventricular arrhythmias. Two-dimensional echocardiography, a noninvasive way of evaluating heart size and function, may show normal ventricular size with thick walls and decreased contractility early in the illness or progressive heart enlargement with thinning of the muscle in chronic cases. Furthermore, the chapter describes dilated cardiomyopathy (DCM), which is a chronic form of heart disease characterized by left and right ventricular dilatation and impaired contraction. The clinical spectrum is broad, ranging from individuals with asymptomatic cardiomegaly to patients who present with severe congestive heart failure.