Evolution of MI

Question 1

Evolution of MI

Answer 1

Coronary artery occlusion:

LAD > RCA > circumflex

Question 2

Symptoms of MI

Answer 2

Diaphoresis, nausea, vomiting, severe retrosternal pain,

pain in left arm or jaw, SOB, fatigue

Question 3

0-4 hrs

Answer 3

Gross change: none
Light microscope: none
Risk: arrythmia, CHF exacerbation, cardiogenic shock

Question 4

4-12 hrs

Answer 4

Light miscroscope: early coag necrosis, edema, hemorrhage, wavy fibers.

Risk: arrhythmias

Question 5

12-24 hrs

Answer 5

Light miscroscope: contraction bands from reperfusion injury, release necrotic cell content into blood, beginning of neutrophil migration

Risk: arrhythmias

Question 6

1-3 days

Answer 6

Light miscroscope: extensive coag necrosis, tissue surrounding infarct shows acute inflammation, neutrophil migration.

Risk: fibrinous pericarditis

Question 7

3-14 days

Answer 7

Light miscroscope: macrophage infiltration followed by granulation tissue at the margins.

Risk: free wall rupture leading to tamponade, papillary muscle rupture, ventricualr aneurysm, IV septal rupture.

Question 8

2 week to several month

Answer 8

Light miscroscope: contracted scar complete

Risk: Dressler’s syndrome