Ischemia 2 Flashcards
Explain how a diagnosis of CAD can be made from an ECG
Resting ECG:
- ST segment changes (usually depression)
- T wave inversion
- Q-waves (indicate prior infarction)
Exercise ECG (stress testing): -dynamic ST segment changes
What are some issues associated with ECG diagnosis?
Resting ECG is insensitive
Exercise ECG sensitivity and specificity are both suboptimal
Explain some aids for interpreting the stress ECG
- Ischemic response - looks like a subendocardial ischemia (downsloping ST depression with exercise)
- Functional information about exercise time and intensity can be mapped to accompanying symptoms to help interpret ECG results
- Imaging of myocardial perfusion or wall motion can improve the sensitivity of stress EKG
Tx for Stable angina?
- Anti-anginal agents (nitrates, beta blockers)
- Control of bp with anti-hypertensives
- Lipid-lowering medication (statin)
- Anti-platelet therapy (aspirin)
Otherwise, need further invasive diagnosis/treatment with coronary angiography
When is CT or direct angiography useful in diagnosing CAD?
- You can see the lumen, but not the wall
- Good for coronary obstruction that may cause symptoms, but cannot predict the future.
- Can guide therapeutic intervention (angioplasty, bypass surgery)
What is a key issue with angiography in assessing CAD?
It underestimates the pathologic extent and severity of dz.
How can you use fractional flow reserve to estimate the severity of a stenosis?
- Measure distal pressure with solid state catheter
- Compare with aortic pressure
- If distal/aortic pressure ration <0.75, then stenosis is significant
How can you use CT for a noninvasive diagnosis of coronary atherosclerosis?
Coronary calcium from atherosclerotic plaque will show up on a CT as a white dots.
How is CAD treated?
- Risk factor modification (such as diet, exercise, smoking cessation)
- Drugs to treat angina, bp, lipids, and platelets
- Revascularization if possible (coronary angioplasty, coronary artery bypass surgery)
Gimme those drugs… that treat coronary heart disease
- Lipid-modifying: statins
- Anti-platelet: Aspirin, clopidogrel
- Anti-anginal: Nitrates, beta blockers, CCB
- LV dysfunction: ACE-I and ARBs
What is the acute treatment of unstable angina?
- Hospitalization
- IV nitro
- B-Blockers
- Aspirin and other anti-platelet agents
- Anticoagulation (heparin)
- Early catheterization and coronary intervention (reduces risk of recurrent ischemic events)
What are the effects of balloon angioplasty on the vessel wall?
Dilation
What are the problems with balloon angioplasty?
- Acute occlusion
- Solution: stents and antiplatelet drugs - Restenosis
- Solution: stents, particularly drug eluting stents (antiproliferative drugs)
Tx of acute MI with ST elevation
- Treatment may be initiated in the field
- Immediate aspirin, nitroglycerin, ± beta blocker
- Reperfusion therapy ASAP: Usually coronary angioplasty, if unavailable thrombolytic therapy.
When might CABG be better than angioplasty? What types of grafts are available?
In the case of multiple blockages use CABG
Types of grafts:
- Internal mammary artery
- Saphenous vein
