ABSTRACT
The relationship between infection and cardiac function was first recognized in the early 1800s when diphtheria was linked with chronic heart failure. Since this original description, the causal relationship between inflammation and heart failure has been clearly identified in many other disease processes and labeled as either myocarditis or cardiomyopathy. This in turn has led to some lack of clarity in the medical literature as to diagnosis, treatment, and outcome in patients presenting in acute or chronic heart failure without a precisely defined etiology. Common practice has been to apply the term' 'cardiomyopathy" to heart disease where an ischemic, congenital, rheumatic, or hypertensive etiology has been excluded. This remains unsatisfactory, however, since the term "cardiomyopathy" is frequently applied to patients with acute myocarditis. With the advent of endomyocardial biopsy and the increasing use of echocardiography, further attempts have been made to achieve a consensus on classification according to morphometry. Based on echo/angiography appearance, cardiomyopathies can be classified into dilated cardiomyopathies, where both left and right ventricles are dilated with poor function; hypertrophic cardiomyopathy, characterized by hypertrophy of the ventricles with pronounced thickening of the interventricular septum; and restrictive cardiomyopathy, which is characterized by reduced diastolic volume with preserved systolic function. In many ways, a more satisfactory classification is to view cardiomyopathies according to their biopsy or postmortem findings (Table 1).
