Cardiology: 8.1a: Angina Flashcards
What is stable angina?
chest pain that arises with exertion or emotional stress
What causes stable angina?
atherosclerosis of coronary arteries with > 70% stenosis OR vasospasm –> decreased blood flow –> not able to meet the metabolic demands of the myocardium during exertion
How much stenosis of the coronary arteries is required before angina occurs?
> 70%
How much of the myocardium receives damage due to stabile angina?
none- it’s reversible and no necrosis occurs
What are the s/s of stable angina?
- chest pain (lasting less than 20 mins)
- pain radiates to L arm or jaw
- diaphoresis
- SOB
What relieves stabile angina?
- rest
- nitro
What EKG findings are seen in stabile angina? Why?
ST-segment depression due to subendocardial ischemia
What is unstable angina?
chest pain that occurs at rest (or increased frequency or intensity of said pain)
What causes unstable angina?
rupture of an atherosclerotic plaque with thrombosis –> incomplete occlusion of a coronary artery
What is the hallmark of reversible cell injury?
cellular swelling
How long does chest pain last in stable angina?
less than 20 minutes
From superficial to deep, what are the 3 muscle layers of the heart?
- Epicardium (most superficial)
- Myocardium (middle)
- Endocardium (deepest)
Which area of heart muscle is most susceptible to ischemic damage?
the subendocardium
Why does nitro relieve stabile agina?
vasodilation of the veins –> decreased preload –> decreased stress on myocytes –> decreased O2 demand
Why does rupture of an atherosclerotic plaque cause thrombosis?
exposure of subendothelial collagen and necrotic material –> activation of clotting cascade –> thrombosis
Does unstable angina result in reversible or irreversible injury?
reversible
What does unstable angina look like on ECG? Why?
- ST-segment depression
- predominantly subendocardial ischemia
What relieves unstable angina?
nitroglycerin
Is there a risk that unstable angina will progress to MI? Why or why not?
YES- high risk bc the thrombus could grow to full occlusion of the vessel
What causes Prinzmetal/variant angina?
coronary artery vasospasm (@ rest)
Does Prinzmetal/variant angina cause reversible or irreversible injury?
reversible
What does Prinzmetal/variant angina look like on ECG? Why?
STEMI bc of transmural ischemia
How can you differentiate Prinzmetal/variant angina from unstable angina?
- both occur at rest and are relieved with NO
- Prinzmetal/variant angina = STEMI; relieved w/ Ca++ channel blockers
- unstable angina = ST depression
What relieves Prinzmetal/variant angina?
- nitroglycerin
- Ca++ channel blockers
What layer of the myocardium is affected by Prinzmetal/variant angina?
all three layers (epi, myo, endo) = transmural ischemia
Why do Ca++ channel blockers relieve Prinzmetal/variant angina?
they help relieve the coronary artery vasospasm
What kind of angina does a STEMI indicate?
Prinzmetal/variant angina
What kind of angina does ST-segment depression indicate?
- stable angina
- unstable angina
Usually the trigger in Prinzmetal/variant angina is unknown, but name 3 known triggers.
- tobacco
- cocaine
- triptans
