Chapter 15 AMI

Question 1

Ischemia pattern

Answer 1

Wider area in the epicardium. Narrower area in the endocardium.
Ischemic area is more negative causing ST depression.
T wave is flipped because of abnormal repol pathway.

Question 2

Injury pattern

Answer 2

Wider area in the epicardium, more narrow in the endocardium similar to ischemia.
Zone of injury does not repol completely, remaining MORE positive than surrounding tissue leading to ST elevation.
T wave is flipped because of abnormal repol pathway

Question 3

Infarction pattern

Answer 3

Thicker endocardium thinner epicardium.
Infarcted areas are electrically neutral, like a window an electrode sees the opposite wall. Heading away from the electrode the vector creates a Q wave. The rest of the complex is formed by the surrounding zones of infarcts and injury

Question 4

Three classes of ACS

Answer 4

Unstable angina
NSTEMI
STEMI

Question 5

UA

Answer 5

Three subtypes new onset, rest, crescendo pattern.
Presents as chest pain, SOB, sweating, palpitations, N/V.
12 reads normal or ST depression and or T-wave inversion.
Lab tests for CK-MB or tropes are negative.
UA represent ischemic state which has not progressed to permanent damage.

Question 6

NSTEMI

Answer 6

Similar to UA with ST depression or T wave inversion. Presents like a stemi often.
Lab values ARE elevated.

Question 7

ECG STEMI criteria

Answer 7

Two or more contiguous leads.

Greater than 2mm in V1 V2 V3. 1mm in all the other leads.

Question 8

II, III, and aVF reciprocal changes

Answer 8

I and aVL

Question 9

V1 and V2 reciprocal changes

Answer 9

V7, V8, V9

Question 10

Old q-wave infarcts often involve

Answer 10

Inferior or anterior walls

Question 11

Inferior infarct arteries

Answer 11

RCA, LCx

Question 12

LCx =

Answer 12

Left circumflex artery

Question 13

Inferior RV infarct arteries

Answer 13

Proximal RCA

Question 14

Inferoposterior infarct arteries

Answer 14

RCA, LCx

Question 15

Isolated RV infarct artieries

Answer 15

LCx

Question 16

Isolated posterior infarct arteries

Answer 16

RCA, LCx

Question 17

Anterior infarct arteries

Answer 17

LAD

Question 18

Anteroseptal infarct arteries

Answer 18

LAD

Question 19

Anteroseptal-lateral infarct

Answer 19

Proximal LAD

Question 20

Anterolateral, inferolateral, or posterolateral

Answer 20

LCx

Question 21

Anterior wall MI

Answer 21

Rarely isolated to anterior. If anterior, septum, and lateral wall are all affected it is called anteroseptal with lateral extension (usually V1-V6 with I and aVL)

Question 22

Anterior septal

Answer 22

V1-V4. Associated with hemodynamic compromise and cardiogenic shock, as are all anterior infarcts. Anterior septal do not show reciprocal changes in the limb leads.. If there is ST depression in II III and aVF the infarct is probably affecting the lateral and high lateral areas of the heart as well.
Reciprocal changes would be right posterior

Question 23

Reciprocal changes

Answer 23

Cannot occur between precordials and limb leads as they lie in a 90 degree angle to one another (different planes) if ST depression is seen it is ischemia or secondary ischemia.

Question 24

Modified sgarbossa criteria

Answer 24

Greater than or equal to 1mm of concordant ST elevation
Greater than or equal to 1mm of ST depression in V1-V3
Greater than or equal to 1mm of concordant STE greater than 25% of the previous S wave

Question 25

General rule for ST elevation in I and II

Answer 25

``` Pericarditis Apical infarct (essentially large inferolateral, ST elevation in every lead except aVR and V1) proximal RCA Aortic dissection causing global infarct (vey rare) ```

Question 26

Why drugs that drop preload (nitrates, beta blockers, diuretics, morphine) fuck up RVIs

Answer 26

LV return is all based on venous pressure, since the RV isn't working.

Question 27

RVI

Answer 27

Elevation in III greater than II IWMI V1 elevation possibly extending to V5 V6 V2 depression UNLESS it extends to V5 V6 ST depression in V2 cannot be more than half the elevation in aVF (otherwise inferior - RV - posterior) More than 1mm elevation in V4R (to V6R) Because it is a RCA inferior wall is usually involved 3% of the time in is caused by an LCx blockage

Question 28

PWMI

Answer 28

Depression in V1 and V2 with upright QRS and upright T waves (often with inferior involvement) Normal R:S ration, flipped T with ST depression more likely anterior ischemia or non-Q wave AMI. Remember RVI should have an asymmetric flipped T