Clinical Recognition of the Cardiomyopathies

Disorders in which the etiology, course, and natural history remain largely unknown are hard to define. When the disorder is confined to the heart muscle, malfunction short of heart failure may give rise to no symptoms. The duration of symptom-free latency may be long and the period of manifest disease short and relatively preterminal. Malfunction of the myocardium does not “speak” to the physician as mitral stenosis does. Its signs are more subtle and seemingly more plebeian. The necessary invasiveness of objective cardiac evaluation has been responsible for a seeming scarcity of hard data. The disorders are often progressive and the myocardial affliction is not necessarily generalized. We lack detailed hemodynamic and angiocardiographic studies (repeated serially throughout each patient's course) and serial biopsies (from appropriate parts of the myocardium) which have been continued until the time of death (in hospital) and necropsy.

Within the severe limitations imposed by these omissions an attempt has been made to clarify the clinical disorders and to define these in relation to the hemodynamic and pathological abnormalities and natural history. The observations and conjectures are based on 300 patients over a 15-year period. Most were followed for only a fraction of the course of their disease; most were catheterized only once or twice; biopsy material was available only once or not at all; many died at home; and many more still survive.

Systolic pump failure, here called dilated or congestive cardiomyopathy, is probably the end result of many causes and is usually nonfamilial. Diastolic compliance failure, hypertrophic cardiomyopathy, is probably homogeneous and genetically determined. Restrictive or obliterative cardiomyopathies usually result from predominantly endocardial disease. The clinical signs are described.