NURS 245 Lecture Notes - Lecture 21: Coronary Artery Disease, Calcium Channel Blocker, Coronary Circulation
Document Summary
Epidemiology-2. 5 million americans living with ischemia (angina pectoris). Million deaths per year (leading cause of death) Initiating event: inadequate oxygen delivery and/or excessive oxygen demand-increased oxygen demand, decreased oxygen delivery. Factors affecting oxygen delivery: coronary blood flow a) Atherosclerosis of coronary arteries (1) (2) (3) (4) Circumflex artery to left ventricle-the side and back of left ventricle (worry about a lot because left ventricle is what is going to pump to the aorta) At any given end diastolic volume your stroke volume goes up=increasing workload=increase oxygen use (1) one way to relieve: use calcium channel blockers after load-anything that increases tpr (aka systemic. Intracardiac effects of ischemia-lack of oxygen causes muscle to contract less which leads to less coronary blood flow and decreased map. Compensation for ischemia causes an increase in oxygen demand (because heart is working harder) Physiological compensations for decreased map-baroreceptor reflex: sympathetics increased heart rate venous constriction: increased preload increased contractility: sympathetics arteriole vasoconstriction: increased work load.
