MI Basics

Question 1

Most Common Occlusions

Answer 1

LAD > RCA > circumflex

Question 2

Evolution of Pathology

Answer 2

0 - 24 hrs - early coag necrosis, wavy fibers, contraction bands from Ca release, neutrophils at end

1-3 days - extensive inflammation / neutrophils

3-14 days - macrophages and granulation tissue; grossly soft yellow

14 days on - gray/white contracted scar

Question 3

Biomarkers

Answer 3

Cardiac troponin - more specific; first to rise (4 hrs but remains elevated for 7-10 days)

CK-MB less specific; rises 6-12 hrs but gone by 48 hrs so good to check recurrence

Question 4

Complications by Time

Answer 4

1st few days - cardiac arrhythmia

1-3 days fibrinous pericarditis

3-14 days - free wall, septal or papillary muscle rupture

3-14 days - pseudoventricular aneurysm

2 wks on - tru ventricular aneurysm, Dresslers (autoimmune), LV fail

Question 5

LAD ECG

Answer 5

V1 - V2

Question 6

Distal LAD ECG

Answer 6

V3- V4

Question 7

Anterolateral MI ECG

Answer 7

LAD or LCX

V5 - V6

Question 8

LCX ECG

Answer 8

I aVL

Question 9

Inferior/ RCA ECG

Answer 9

II, III, aVF

Question 10

PDA ECG

Answer 10

V7-V9, ST depression in V1-V3 w/ tall R waves

Question 11

Unstable Angina / NSTEMI Tx

Answer 11

• Anti coag
• Anti-platelet
• ADP rec inhibitor (clopidogrel)
• Beta blocker
• ACE inhibitor
• Statin
• Tx of symptoms w/ nitroglycerin and morphine

Question 12

STEMI Tx

Answer 12

Same as NSTEMI + percutaneous coronary intervention