M4 Group Ischemia

Question 1

Any type of “new” ischemia that last less than 2 weeks is considered what type of angia?

Answer 1

unstable, therefore all angina begins as unstable angina

Question 2

Do you expect to see changes on EKG for unstable angina, NSTEMI and/or STEMI?

Answer 2

only for NSTEMI and STEMI, in the case of STEMI, specifically an S-T elevation

Question 3

What is the predictive value of a stress test?

Answer 3

it offers low specificity and selectivity, although its predictive power is increased by using the test in a high risk population

Question 4

What are the actions of the following drugs to target the supply/demand of O2 to the heart: aspirin, B-blocker, oxygen, nitrates.

Answer 4

Aspirin- inhibit platelet aggregation, stop the clotting associated with the ruptured plaque (increase supply)
B-blocker- decrease demand–decrease his heart rate, decrease blood pressure (decreased afterload/wall stress) and increase myocardial perfusion
Oxygen: Lower peoples anxiety, lower HR
Nitrates: venodilation- decrease blood supplied to the heart- less preload→ less contractility, coronary vessels are maximally vasodilated; counter thromboxane

Question 5

When would you expect troponin levels to rise in a patient with AMI?

Answer 5

4-6 hours after the initial symptoms, follow with serial troponins until peak (usually 24hours)

Question 6

Describe the confounding factors that make nuclear imaging misleading on a patient with 3 vessel stenosis/occlusion)

Answer 6

because the nuclear imaging uses a comparison from at rest to at stress, the change in perfusion may not change significantly if blood flow is very low to begin with, that there is a consistent level of ischemia in the heart, not highlighting areas of ischemia

Question 7

How much of an occlusion would you require to get ischemia at rest?

Answer 7

around 90% occlusion; even with a 70% occlusion, you would need stress to bring out any ischemia