Cardiomyopathy Basics

Cardiomyopathy is disease of the myocardium—the heart muscle—that changes ventricular structure, function, or both. The ventricle may become enlarged and weak, abnormally thick, stiff, or prone to dangerous ventricular arrhythmias. The result is impaired filling, impaired ejection, or both. Contemporary classification is based on phenotype: - Hypertrophic cardiomyopathy (HCM): unexplained thickening of the left ventricular wall, often from an inherited sarcomere disorder. - Dilated cardiomyopathy (DCM): ventricular dilation with reduced systolic pump function. - Non-dilated left ventricular cardiomyopathy (NDLVC): left ventricular scarring or dysfunction without the dilation expected in classic DCM. - Arrhythmogenic right ventricular cardiomyopathy (ARVC): fibrofatty replacement of myocardium, usually involving the right ventricle and creating a high arrhythmia risk. - Restrictive cardiomyopathy: stiff ventricles that cannot relax and fill normally; infiltrative disease such as amyloidosis is an important cause. The experienced nurse first notices the consequence of poor cardiac performance: exertional dyspnea, fatigue, edema, chest discomfort, palpitations, or syncope. Those symptoms do not identify the phenotype by themselves. Their pattern, the echocardiogram, rhythm findings, and family history help separate one cardiomyopathy from another.