4. CAD 3/13

Question 1

1. what is atherosclerosis?
2. what causes it?
3. what is it the major cause of?

Answer 1

1. an “inflammatory” condition that can be caused by infection, hyperlipidemia, injury to vascular endothelial cells, vasoconstricting hormones.
2. increased age, HTN, diabetes mellitus, smoking, obesity, high fat diet, family hx, psychosocial stress, hyperlidemia
3. major cause of coronary artery and cerebrovascular disease( most common cause of CAD and MI).

Question 2

1. what is CAD (in regards to atherscleorsis)

2. how does this affect the myocardium?

Answer 2

1. plaque forms within the intimal layer in the coronary arteries (can happen anywhere in the body) leads to thickening and hardening of arteries.
2. when the tiunica intima stiffens and thickens, the arteries ability to contract and expand is hindered, therefore oxygenation is hindered.

Question 3

myocardial oxygen supply is decreased by:

Answer 3

Decreased Myocardial Oxygen Supply-examples
1. Decreased Coronary Blood Flow
• Tachycardia
– Decreases perfusion time
– Is the most important of all physiologic factors that can be altered to reduce demand
– Increases in HR causes an increase in oxygen consumption and reduces perfusion in regions distal to the coronary artery stenosis by reducing the duration of diastole.
• Diastolic hypotension
– Recall: CPP = diastolic pressure - left ventricular diastolic pressure
• Increased preload
• Hypocapnia
• Coronary spasm
2. Decreased Arterial Oxygen Delivery/ Arterial Oxygen Content-examples
• Anemia
• Hypoxia
• Decreased 2,3 DPG

Question 4

increased myocardial oxygen demand causes:

Answer 4

Increased Myocardial Oxygen Demand-examples
• Tachycardia
• Increased Wall Tension
• Increased Contractility

Question 5

Myocardial O2 Supply and Demand

Answer 5

Normally, when oxygen demand increases there is a proportionate increase in coronary blood flow and oxygen supply.
When demand exceeds supply, then this imbalance results in myocardial ischemia.