Chapter Summary

Ischemic heart disease, the most common cause of death in the United States, is the consequence of cardiac ischemia usually secondary to coronary artery disease.

Angina pectoris refers to transient cardiac ischemia (without cell death) resulting in substernal pain. Variants of angina include stable angina, Prinzmetal variant angina, and unstable angina.

Myocardial infarction is a localized area of cardiac muscle necrosis due to ischemia and can occur as the result of either coronary artery atherosclerosis with superimposed thrombus formation or coronary artery spasm. Myocardial infarction often presents with sudden onset of severe "crushing" substernal chest pain that may radiate to the left arm, jaw, and neck. EKG changes and elevation of cardiac serum markers confirm the diagnosis. Myocardial infarction has a wide variety of complications that can cause death.

Congestive heart failure is insufficient cardiac output to meet the metabolic demands of the body's tissues and organs. Left heart failure can complicate ischemic heart disease, hypertension, myocardial diseases, and aortic or mitral valve disease. It is associated with left ventricular hypertrophy and dilatation, passive pulmonary congestion and edema, activation of the renin-angiotensin-aldosterone system leading to hyperaldosteronism, and cardiogenic shock. Right heart failure can complicate left heart failure, pulmonary or tricuspid valvular disease, and cor pulmonale. It causes jugular venous distension, hepatosplenomegaly, dependent edema, and ascites.

Degenerative calcific aortic valve stenosis, the most common valvular abnormality, is an age-related dystrophic calcification, degeneration, and stenosis of the aortic valve that can cause concentric left ventricular hypertrophy, congestive heart failure, and an increased risk of sudden death.

Mitral valve prolapse is a myxomatous degeneration of the mitral valve that causes the valve leaflets to become enlarged and floppy.

Rheumatic fever is a systemic inflammatory disease, triggered by a pharyngeal infection with Group A beta-hemolytic streptococci', that in genetically susceptible individuals results in the production of antibodies that cross-react with cardiac antigens. Acute rheumatic heart disease can produce myocarditis, pericarditis, and endocarditis. Chronic rheumatic heart disease can damage the mitral and aortic valves, secondarily predisposing for mitral stenosis, congestive heart disease, and infective endocarditis.

j j Infective bacterial endocarditis is a bacterial infection of the cardiac valves, characterized by vegetations on the valve leaflets. Risk factors include previous damage to valves, congenital heart disease, and sources of bacteremia. Acute endocarditis is caused by high-virulence organisms, notably Staphylococcus aureus, and produces large destructive lesions with a high mortality rate. Subacute endocarditis is caused by low-virulence organisms, notably viridans streptococci, and usually involves previously damaged valves.

Marantic endocarditis refers to the formation of small, sterile vegetations along the valve leaflet line of closure in patients with debilitating diseases.

Congenital heart disease is the most common cause of childhood heart disease in the United States and may be idiopathic or associated with genetic disease, infection, or drug and alcohol use.

Coarctation of the aorta is a segmental narrowing of the aorta that is subdassified, depending upon the level at which the narrowing occurs, into preductal coarctation (poorer prognosis, association with Turner syndrome) and postductal coarctation (late onset).

Your Heart and Nutrition

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