Myocardial Ischemia Flashcards
Define myocardial ischemia
An imbalance of oxygen demand and oxygen supply TO THE HEART
What are the 2 targets for increasing O2 supply? Which is more important?
AV oxygen difference
Regional Myocardial distribution (more important
What is the characteristic symptom of myocardial ischemia?
Angina pectoris (chest pain) (due to buildup of metabolites in muscle tissue)
What are the 5 types of myocardial ischemia?
Stable angina (atherosclerotic block of coronary artery)
Unstable Angina (rupture of atherosclerotic plaque)
Silent/Effort Ischemia (asymptomatic until exercise is required)
Variant Angina (no obvious cause, possibly stress)
Myocardial infarction (death of tissue)
Define atherosclerosis
Deposition of fatty substances, esp. cholesterol/fatty acids in arteries
What is a coronary artery spasm?
Surprise death, unknown cause
Where do each of the two types of atherosclerosis take place?
Endothelium-smooth muscle interface
Ruptured lesion in endothelium
Drugs against myocardial ischemia provide one of two effects, what are they?
Reduce O2 demand / improve coronary flow
Slower development of ischemia
Name a nitrate, describe its mechanism of action, and possible side effects
Nitroglycerin
Increases cAMP through GPCR cascade, which leads to muscle relaxation
-> reduction of venous return, cardiac size & diastolic myocardial oxygen consumption
- Orthostatic hypotension
- Tachycardia
- Headache
Name 3 calcium channel blockers, describe their mechanism of action, and list possible side effects
Verapamil
Nifedipine
Diltiazem
peripheral vasodilation, reduction of cardiac work
- Orthostatic hypotension
- AV blockade
- Edema
Name a beta blocker, describe its mechanism of action, and possible side effects
Propranolol
Reduces blood pressure/cardiac work
- Orthostatic hypotension
- Tachycardia
- Headache
What drugs would be prescribed for someone with effort Angina?
Nitrates Ca channel blockers (prophylactic) Beta blockers (v important)
What drugs would be prescribed for someone with Variant angina?
NItrates
Ca channel blockers (prophylactic)
What drugs would be prescribed for someone with Acute Coronary Syndrome?
Nitrates Beta blockers (very important)
True/False? Drugs are the only way to prevent atherosclerosis
False (lots of ways to control, but people avoid them because they require effort)