Differentiation of the Types of Acute MI

Question 1

An Inferior MI is associated with occulsion of what structure?

Answer 1

Right coronary artery

Question 2

What and where will you see changes in an INFERIOR MI?

Answer 2

ST elevation in II, III, aVF

with reciprocal changes in lateral wall (I, aVL)

Question 3

Inferior MI is associated with AV conduction disturbances: what are they?

Answer 3

2nd-degree Type I AV Block (progressive PR and dropped beat; mobitz I, or wenekbach)

3rd-degree AV Block (P and Q don’t agree)

Sick sinus syndrome (SSS <40bpm, sinus pauses, sinus arrest)

Sinus bradycardia

Question 4

Inferior MI is often associated with the development of what type of murmur?

Answer 4

Systolic Murmur: mitral valve regurgitation (MVR) 2/2 papillary muscle rupture (recall that the posterior papillary muscle has only one source of blood supply, the RCA)

Question 5

Is bradycardia or tachycardia associated with inferior MI?

Answer 5

tachycardia (which can increase mortality)

Question 6

Inferior MI is also associated with what other type of infarction?

Answer 6

Right ventrcular infarction and posterior MI

Question 7

What drugs do you want to USE CAUTIOUSLY in an inferior MI

Answer 7

Beta blockers and NTG (remember, Inferior MI are often associated with AV conduction disturbances, and beta blockers can further exacerbate it)

Question 8

What are some signs and symptoms of a Right Ventricular Infarction?

Answer 8

JVD at 45 degrees

High CVP (normal 2-8); high can indicate hypovolemia

Hypotension

Clear Lung Sounds

Bradyarrhythmias

ST elevation in V3R and V4R

Question 9

How is a Right Ventricular Infarct treated?

Answer 9

Fluids and positive inotropes

Question 10

What meds do you want to avoid for Right Ventricular Infarcts?

Answer 10

Preload reducers (nitrates and diuretics)

Beta-blockers (patient is typically hypotensive as is)

Question 11

What leads would you expect to find ST elevation for Right Ventricular Infarct?

Answer 11

V3R, V4R

Question 12

An anterior MI is associated with what coronary structure?

Answer 12

Left Anterior Descending (also supplies bundle of his) oclusion

Question 13

What leads would you see an ST elevation for an Anterior MI?

Answer 13

V1 through V4

Question 14

In an Anterior MI, where do you see reciprocal changes (ST depression)?

Answer 14

Inferior wall, leads II, III, aVF

Question 15

What type of heart block may develop from an Anterior MI?

Answer 15

2nd degree Type II AV Block (Mobitz II) or RBBB

“If you have more P’s than Q, then you have a Mobitz II”

QRS complex is dropped

Question 16

What type of murmur can develop as a result of Anterior MI?

Answer 16

Systolic Murmur; possible ventricular septal defect

Question 17

What has a higher mortality: Inferior or Anterior?

Answer 17

Anterior

Question 18

Your patient has a Low Lateral MI. Where would you see ST elevation on an ECG?

Answer 18

V5, V6 (low lateral)

Question 19

Your patient has a HIGH Lateral MI. Where would you see ST elevation on an ECG?

Answer 19

I, aVL (high lateral)

Question 20

Lateral MI often involves which artery?

Answer 20

Left circumflex