Medical brain notes 15

  ISCHEMIC HEART DISEASE Cardiac ischemia  is usually secondary to coronary artery disease (CAD); it is themost common cause of death in the United States. It is most often seen in middle-age men and postmenopausal women. Angina pectoris  is due to transient cardiac ischemia without cell death resulting insubsternal chest pain.   ·              Stable angina  (most common type) is caused by coronary artery atheroscle-rosis with luminal narrowing >75%. Chest pain is brought on by increased cardiac demand (exertional or emotional), and is relieved by rest or nitroglyc-erin (vasodilation). Electrocardiogram shows ST segment depression (suben-docardial ischemia).   ·              Prinzmetal variant angina   is caused by coronary artery vasospasm and produces episodic chest pain often at rest; it is relieved by nitroglycerin (vasodilata...

  CONGESTIVE HEART FAILURE Congestive heart failure  (CHF) refers to the presence of insufficient cardiac outputto meet the metabolic demand of the body’s tissues and organs. It is the final com-mon pathway for many cardiac diseases and has an increasing incidence in the United States. Complications include both  forward failure  (decreased organ per-fusion) and  backward failure  (passive congestion of organs). Right- and left-sided heart failure often occur together.   ·              Left heart failure  can be caused by ischemic heart disease, systemic hyperten-sion, myocardial diseases, and aortic or mitral valve disease. The heart has increased heart weight and shows left ventricular hypertrophy and dilatation. The lungs are heavy and edematous. Left heart failure presents with dyspnea, orthopnea, paroxysmal nocturnal dyspnea, rales, and S3 gallop.   Microscopically, the heart sh...

  VALVULAR HEART DISEASE Degenerative calcific aortic valve stenosis  is a common valvular abnormality char-acterized by age -related dystrophic calcification, degeneration, and stenosis of the aortic valve. It is common in congenital bicuspid aortic valves. It can lead to concen-tric left ventricular hypertrophy (LVH) and congestive heart failure with increased risk of sudden death. The calcifications are on the outflow side of the cusps. Treat-ment is aortic valve replacement. Mitral valve prolapse  has enlarged, floppy mitral valve leaflets that prolapse intothe left atrium and microscopically show myxomatous degeneration. The condi-tion affects individuals with Marfan syndrome. Patients are asymptomatic and a mid-systolic click can be heard on auscultation. Complications include infectious endocarditis and septic emboli, rupture of chordae tendineae with resulting mitral insufficiency, and rarely sudden death.   Rheumatic valvular heart disease/acute rheumatic fe...

  MYOCARDITIS Myocarditis  is caused by infectious (coxsackie A and B viruses, Chagas disease) andimmune causes. Clinically, the patient may be asymptomatic or may suffer from acute heart failure or even dilated cardiomyopathy.

  CONGENITAL HEART DISEASE Congenital heart disease  is the most common cause of childhood heart disease inthe United States; 90% of cases are idiopathic and 5% are associated with genetic disease (trisomies, cri du chat, Turner syndrome, etc.), viral infection (especially congenital rubella), or drugs and alcohol. Coarctation of the aorta  is a segmental narrowing of the aorta. ·              Preductal coarctation  (infantile-type) is associated with Turner syndrome andcauses severe narrowing of aorta proximal to the ductus arteriosus. It is usu-ally associated with a patent ductus arteriosus (PDA), which supplies blood to aorta distal to the narrowing, and right ventricular hypertrophy (secondary to the need for the right ventricle to supply the aorta through the patent ductus arteriosus). It presents in infancy with congestive heart failure that is accom-panied by weak pulses and cyanosis in the lower ext...

  PRIMARY CARDIOMYOPATHIES (DIAGNOSIS OF EXCLUSION) Dilated cardiomyopathy  (most common form) is cardiac enlargement with dilatationof all 4 chambers, resulting in progressive congestive heart failure (typical mode of presentation). The cause is genetic in 20–50% of cases, but some cases are related to alcohol, medications (Adriamycin [doxorubicin]), cocaine, viral myocarditis (Cox-sackievirus B and enteroviruses), parasitic infections (Chagas disease), iron overload or pregnancy. In cases of all types, the underlying etiology leads to destruction of myocardial con-tractility, which affects systolic function. Echocardiogram typically shows decreased ejection fraction. Complications include mural thrombi and cardiac arrhythmias; prognosis is poor with 5-year survival of 25%. Treatment is heart transplantation. There is myocyte hypertrophy with interstitial fibrosis on microscopy, and eccentric hypertrophy seen on gross examination. Hypertrophic cardiomyopathy  (also calle...

  CARCINOID HEART DISEASE Carcinoid heart disease  is right-sided endocardial and valvular fibrosis secondaryto serotonin exposure in patients with carcinoid tumors that have metastasized to the liver. It is a plaque-like thickening (endocardial fibrosis) of the endocardium and valves of the right side of the heart. Many patients experience carcinoid syndrome (also related to secretion of serotonin and other metabolically active products of the tumors), characterized by skin flushing, diarrhea, cramping, bronchospasm, wheezing, and telangiectasias. The diagnosis can be established by demonstrating elevated urinary 5-hydroxyindoleacetic acid (5-HIAA), a metabolite of the break-down of serotonin via monoamine oxidase.

  CARDIAC TUMORS Primary cardiac tumors are rare. The majority are benign; the malignant tumors are sarcomas. Treatment is excision. ·              Cardiac myxoma  is a benign tumor usually arising within the left atrium nearthe fossa ovalis in decades 3-6 of life; it can present like mitral valve disease. In 10% of cases there is an autosomal dominant condition known as Carney complex (myxomas with endocrine abnormalities and lentigines or pigmented nevi). Cardiac myxoma is characterized microscopically by stellate-shaped cells within a myxoid background. Complications include tumor emboli and “ball-valve” obstruction of the valves.   ·              Cardiac rhabdomyoma  is a benign tumor usually arising within the myo­cardium that is associated with tuberous sclerosis.

  PERICARDIAL DISEASE Pericarditis. There are 2 kinds of pericarditis, acute and chronic. ·              Acute pericarditis  is characterized by a fibrinous exudate (viral infection oruremia) or by a fibrinopurulent exudate (bacterial infection).   ·              Chronic pericarditis  can occur when acute pericarditis does not resolve andadhesions form.   Pericardial effusion  may be serous (secondary to heart failure or hypoalbuminemia),serosanguineous (due to trauma, malignancy, or rupture of the heart or aorta) or chylous (due to thoracic duct obstruction or injury). Tumors of the lung and breast may spread by  direct extension  to the pericardia.