HSS 3305 Lecture Notes - Lecture 13: Purkinje Fibers, Coronary Circulation, Circulatory System
Document Summary
Blood pressure during cardiac diastole declines slowly as blood leaves the large arteries through the arterioles into the capillaries: elasticity of the large arteries also influences the systolic pressure. Cause arteriosclerosis of coronary arteries; narrowing of arteries from lipid deposits (neutral fat and cholesterol) by diffusion from bloodstream. Risk factors elevated blood lipids, high blood pressure, cigarette smoking, diabetes. Likelihood of coronary heart disease and heart attack: 1 risk factor = 2x risk; 2 risk factors = 4x risk; 3 risk factors = 7x risk, other risk factors obesity, type a personality. Severe and prolonged myocardial ischemia may precipitate an acute episode of heart attack: mrocardial infarction actual necrosis of heart muscle. Treatment - myocardial revascularization procedures: bypass surgery use segment of saphenous vein of internal mammary arteries to bypass obstruction, coronary angioplasty dialate narrowed coronary arteries rather than bypassing them.