NURS 245 Lecture Notes - Lecture 14: Coronary Catheterization, Coronary Artery Disease, Ischemia
Document Summary
Myocardial infarction is the leading cause of death with million deaths a year. More common in males, over the age of 65, cad, htn. Estrogen protects against atherosclerosis and ischemia which is why during menopause, the number of women affected by atherosclerosis rises due to lack of estrogen. There"s only coronary blood flow during diastole and when the heart rate increases, it shortens the time of diastole therefore decreasing the amount of oxygen that can be delivered. Increase in heart rate is controlled by the sympathetic system (originating in the brainstem) that triggers the fight or flight response. An increase in sympathetic response increases workload of heart increases oxygen use. An increase in total peripheral resistance (tpr) increases the workload of heart. Can be caused by an increase in muscle mass. Ischemia works as a positive feedback; the problem causes a compensation that leads to more problems. Blockage of right or left coronary arteries can cause ischemia.
