A 17-year-old high school student dies suddenly while playing basketball.Autopsy and histologic sections are given. What is the most likely diagnosis?
Hyperophic cardiomyopathy is characterized by asymmetric hyperophy of the interventricular septum, histologic sections of which reveal disorganized, hyperophied myofibers. These changes produce hypercontractility that predisposes patients to the risk of sudden death. There is an increased incidence of hyperophic cardiomyopathy within families, and there is evidence that it may be an autosomal dominant disorder. The disease is thought to result from a mutation in the cardiac b-myosin heavy chain gene. Patients may experience dyspnea, lightheadedness, and chest pain, especially upon physical exeion; however, many patients appear to be asymptomatic, although sudden, unexpected death occurs not infrequently, especially following or during physical exeion. This risk is increased with factors that either increase the contractility of the hea or decrease the volume of the left ventricle (both of which increase the left ventricular outflow obstruction). T reatment for patients with hyperophic cardiomyopathy, therefore, is with drugs that decrease contractility. Examples of these types of drugs include b-adrenergic blockers and calcium channel blockers. In individuals with hyperophic cardiomyopathy, agents that increase contractility are contraindicated. Examples of these types of drugs include glycosides, such as digitalis. Epinephrine and b-adrenergic agonists, which increase cardiac output by increasing stroke volume and hea rate, would also be contraindicated. Diuretics would also be dangerous, as they would decrease intravascular volume, and this would accentuate the bad effects of the septal hyperophy because of the decreased left ventricular volume. dilated (congestive) cardiomyopathy results in a flabby, hypocontractile hea. Constrictive (restrictive) cardiomyopathy is associated in the United States with amyloidosis and endocardial fibroelastosis. It is so named because of the infiltration and deposition of material in the endomyocardium and the layering of collagen and elastin over the endocardium. This deposition affects the ability of the ventricles to accommodate blood volume during diastole. Reference: Robbins & Cotran Pathologic Basis of Disease, 9edition.
Hyperophic cardiomyopathy
Dilated cardiomyopathy
Constrictive cardiomyopathy
Secondary cardiomyopathy
Cardiovascular system