Ischemic Heart Disease I Flashcards
What are the 2 types of risk factors** for **Atherosclerosis?
- Modifiable
- Non-Modifiable
What are the Modifiable risk factors for atherosclerosis?
Modifiable
- Hypertension (HTN)
- Hypercholesterolemia (LDL increases risk, HDL decreases risk, Inc Triglycerides)
- Smoking (inc of 50%)
- Diabetes, obesity, inflammation etc. (technically unclear if risk is reduced by treatment)
What are the non-modifiable risk factors for atherosclerosis?
Non-modifiable
- Age
- Gender (male and post menopausal females)
- Genetics
Which type of cholesterol, when deposited in vascular endothelium, is injurious and pro-inflammatory?
LDL
What are the 3 basic steps in the pathophysiology of Atherosclerosis?
- Damage to the endothelium allows lipids to leak into intima
- Lipids are oxidized and consumed by macrophages.
- “Fatty” macrophages become Foam Cells
- Inflammation and healing leads to deposition of extracellular matrix (plaque formation)
Define Stable Coronary Artery Disease (aka Stable angina).
Obstructive lesion limits blood flow to heart, causing myocardial ischemia and angina. This occurs upon exertion or increased cardiac oxygen demand.
How is the coronary circulation different from other circulations in the body?
- Myocardium debends on aerobic metabolism
- Heart takes maximal O2 from blood. Only way to increase myocardial O2 is to increase blood flow rate.
- Left ventricle is perfused in diastole only.
How does the body regulate Coronary blood flow rate?
- Controlling Perfusion Pressure
- Perfusion time (time in diastole)
- Vascular Resistance
Between 60 and 120 mmHg, there is little change in coronary flow. Why does this happen?
AUTOREGULATION of the small arterioles (remember these suckers from last test? This is where pressure is controlled)
- In coronary heart disease, autoregulation mayu be exhausted
What are the 3 factors that control Myocardial O2 Supply?
- Coronary Flow Rate
- O2 content of blood
- O2 delivery
True or False:
Tacchycardia compromises coronary flow
True
Coronary flow occurs predominantly during Diastole.
What are the 4 factors to consider when trying to elevate O2 supply for a Stable Angina? What is our treatment goal for each factor?
- Perfusion Pressure
- prevent hypotension
- Diastolic time
- Slow heart rate (beta blocker)
- Cornoary resistance
- Dec Resistance via vasodilators, angioplasty or bypass surgury
- O2 Content
- treat anemia or hypoxemia
What are the 4 factors to consider when trying to decrease O2 demand for a Stable Angina? What is our treatment goal for each factor?
- Systolic Pressure
- Antihypertensive drugs
- Heart Rate
- Slow heart rate (beta blocker)
- Wall Tension
- Limit LV size by decreasing preload (diuretics, nitrates)
- Iontropic State
- Negative inotropes to decrease inotropy
Describe Unstable CHD.
Pain even while resting due to an almost completely occlusive or ruptured plaque.
Plaques Rupture and throw off thrombi. Leads to Acute MI
Describe the pathophysiology of Unstable CHD.
Inflammation in the arterial wall, the fibrous cap containing the plaque weakens –> rupture –> thrombogenic components exposed to blood –> thrombosis + vessel occlusion –> MI/necrosis –>cardiac dysfunction, arrhythmia, death.
