Cardiomyopathy = disease of the heart muscle
Diseases are classified on predominant clinical presentations:
- o Dilated cardiomyopathy – ventricular dilatation
- o Hypertrophic cardiomyopathy – myocardial hypertrophy of interventricular septum and ventricular walls
- o Restrictive cardiomyopathy – impaired ventricular filling
- o Arrhythmogenic right ventricular cardiomyopathy – prominent right ventricular involvement with a high frequency of ventricular arrhythmias (=epsilon waves on ECG)
- o Other rare cardiomyopathies. (Chagas disease is an important cause in Central and South America)
An intrinsic cardiomyopathy is defined as weakness in the muscle of the heart that is not due to an identifiable external cause.
Alcoholism has been identified as a cause for some forms of dilated cardiomyopathy.
To make a diagnosis of an intrinsic cardiomyopathy, significant coronary artery disease should be ruled out. The term intrinsic cardiomyopathy does not describe the specific etiology of weakened heart muscle. The intrinsic cardiomyopathies consist of a variety of disease states, each with their own causes.
Many intrinsic cardiomyopathies now have identifiable external causes (=’extrinsic CMPs)
- drug and alcohol toxicity
- certain infections (including Hepatitis C)
- various genetic and idiopathic (i.e., unknown) causes.
Secondary CMPs: infiltrative disease, storage, toxicity, inflammatory, endocrine, neuromuscular, autoimmune.