Stephanie Acosta, MD
Dilated cardiomyopathy (DCM) is a myocardial disorder characterized by left ventricular chamber enlargement and systolic dysfunction that often manifests as congestive heart failure. It is characterized by progressive dilation with impaired systolic function of the left ventricle (in some cases both ventricles) with normal ventricular wall thickness. It is the most common form of pediatric cardiomyopathy. DCM leads to progressive heart failure and a decline in LV contractile function, ventricular and supraventricular arrhythmias, conduction system abnormalities, thromboembolism, and acute and/or chronic heart failure. DCM has a broad range of primary (and secondary) causes, including the following: infectious agents, particularly viruses, often producing myocarditis (coxsackievirus, adenovirus, parvovirus, HIV); bacterial; fungal rickettsial; myobacterial; and parasitic (eg, Chagas disease resulting from Trypanosoma cruzi infection). Other causes include toxins; chronic excessive consumption of alcohol; chemotherapeutic agents (anthracyclines such as doxorubicin and daunorubicin); metals and other compounds (cobalt, lead, mercury, and arsenic); autoimmune and systemic disorders (including collagen vascular disorders); pheochromocytoma; neuromuscular disorders such as Duchenne/Becker and Emery-Dreifuss muscular dystrophies; and mitochondrial, metabolic, endocrine, and nutritional disorders (eg, carnitine, selenium deficiencies). About 20% to 35% of DCM cases have been reported as familial, although with incomplete and age-dependent penetrance, and linked to a diverse group of 20 loci and genes. The single largest cause of DCM in individuals under 18 years of age is myocarditis. In the pediatric population, the primary etiology for myocarditis is viral or post viral infection.
Echocardiography involves assessment of systolic left and right ventricular function. It is important to evaluate left ventricular dimensions, wall thickness, volumes, mass, wall stress, rate corrected velocity of circumferential fiber shortening, shortening fraction, ejection fraction and sphericity for presence and severity of ventricular dilation and dysfunction.