Cardiomyopathy Basics

Cardiomyopathy is a disorder in which the myocardium is structurally or functionally abnormal and coronary artery disease, hypertension, valvular disease, or congenital heart disease does not adequately explain the abnormality. The cause may be genetic or acquired. A family history of cardiomyopathy, heart failure, cardiac arrest, or unexplained sudden death therefore matters during assessment. A phenotype describes the dominant structural and functional pattern: - Hypertrophic cardiomyopathy (HCM): unexplained thickening of the left ventricular myocardium. The thick ventricle relaxes poorly. In obstructive HCM, systolic anterior motion of the mitral valve and septal hypertrophy can narrow the left ventricular outflow tract. - Dilated cardiomyopathy (DCM): left or both ventricles enlarge and systolic contraction is impaired. Forward flow falls, while blood backs up into the pulmonary and systemic circulations. - Non-dilated left ventricular cardiomyopathy (NDLVC): left ventricular myocardial disease can appear as non-ischaemic scar or fatty replacement, with or without abnormal wall motion, even without marked chamber dilation. - Arrhythmogenic right ventricular cardiomyopathy (ARVC): right ventricular myocardial scar or fatty replacement creates an arrhythmia-prone substrate. - Restrictive cardiomyopathy: stiff ventricles fill poorly despite...