Myocardial Infarction

Question 1

What percent of annual MIs are due to a STEMI?

Answer 1

30%

Question 2

What is the main cause of a STEMI?

Answer 2

Atherosclerosis:

Buildup of plaque in vessels —> erosion of this plaque will cause the release of cytokines —> recruitment of platelets —> Formation of a Thrombus (this will ultimately lead to occlusion of the vessel)

Question 3

Besides Atherosclerosis, what are 4 other causes of STEMI?

Answer 3

Vasospasm
Vasculitis
Genetics
Dissection (surgical procedure)

Question 4

What vessel is associated with the anterior wall?

Answer 4

LAD (widowmaker)

Question 5

What vessel is associated with the lateral wall?

Answer 5

Circumflex A.

Question 6

What vessel is associated with the posterior wall?

Answer 6

Posterior Descending A.

Question 7

What vessel is associated with the inferior wall?

Answer 7

Right Coronary A.

Question 8

What is defined as an ischemia?

Answer 8

Reduced blood flow to tissue resulting in failure to repolarize

Question 9

What is defined as a myocardial injury?

Answer 9

Reduced blood flow to tissue results in reduced depolarization

Question 10

What is defined as an infarction?

Answer 10

Necrotic tissue results in failure to depolarize.

Question 11

What is the timeline for cardiac biomarkers Of necrosis?

Answer 11

Troponin I:
Appear:  1-4 hours after onset
Peak at: 10-24 hours after onset
Persist for: 5-14 days
*Renal failure can give you a false positive for Troponin I levels.

Question 12

What are the cardiac enzymes that indicate an NSTEMI or NSTE ACS?

Answer 12

Troponin, IRT, CKMB

ELEVATED during NSTEMI

NORMAL levels during NSTE ACS

Question 13

What are the clinical presentations of a myocardial infarction?

Answer 13

• Heavy chest pain (“elephant sitting on chest”)
• Levine sign (fist over chest)
  Coughing, hemoptysis
  Fatigue, weakness
  Dyspnea, orthopnea, wheezing
  Pain in extremity
  Nausea
  Failure to treat with Nitro
  Retrosternal radiation of pain into jaw, UE, chest, neck
  Sweaty