8. Infarction

Question 1

describe subendocardial ischemia

Answer 1

• ischemica is then represented by an inverted T wave
• ST axist shifts away from affected ventricle (ST depression)

Question 2

describe transmural ischemia

Answer 2

• T wave axis directs toward the area of the LV
• creates hyperacute T waves
• ST segment axis shifts toward the affected area (ST elevation)

Question 3

what can heart injury show on EKG

Answer 3

• hyperacute T waves which peak 30 min post injury
• no cellular death

Question 4

general rule for determining if T wave is hyperacute

Answer 4

if you can fit the QRS inside the T, it’s hyperacute

Question 5

Wellen’s Syndrome

EKG findings

Answer 5

marked T wave inversion (or biphasic T waves) in V2-V4

Question 6

Wellen’s Syndrome

associated with?

Answer 6

critical stenosis of the LAD artery (widow maker)

Question 7

what does ST segment elevation represent

Answer 7

that the myocardium is at risk for irreversible infarction

Question 8

STEMI criteria

Answer 8

• > 1 mm elevation in 2+ limb leads or V4, V5, or V6
• > 2 mm elevation in 2+ precordial leads (V1, V2, V3)
• > 1mm depression in 2+ precordial leads (V1, V2, V3) (posterior MI)

Question 9

other causes of ST elevation

Answer 9

• benign early repolarization
• pericarditis
• LV aneurysm
• Printzmetal’s Angina
• BBBs

Question 10

describe the J point

Answer 10

transition from the QRS to the ST segment

Question 11

causes of ST segment Depression

4

Answer 11

• posterior STEMI
• reciprocal lead changes in STEMI
• NSTEMI/unstable angina
• subendocardial ischemia

Question 12

Necrosis on EKG

Answer 12

• significant Q waves
• will disappear in 1/4 of pts w/ acute MI

Question 13

criteria for being a significant Q wave

Answer 13

• width of 1mm
• height is 1/3 total amplitude of QRS
• look at all leads except aVR

Question 14

what do L and R coronary arteries arise from?

Answer 14

aorta

Question 15

what does the LCA divide into?

Answer 15

circumflex and anterior descending

Question 16

what does RCA divide into?

Answer 16

marginal and posterior descending

Question 17

what does RCA supply?

Answer 17

SA node, AV node, HIS bundle

Question 18

what does LAD supply

Answer 18

anterior & septal region of LV and septum

Question 19

what does L circumflex supply?

Answer 19

lateral wall of LA and LV

Question 20

what does RCA supply

Answer 20

RV and posterior LV

Question 21

Where to look on EKG for anterior MI? what vessel is impacted?

Answer 21

• V1-V3
• LAD

Question 22

Where to look on EKG for lateral MI? what vessel is impacted?

Answer 22

• I, aVL, V5, V6
• left circumflex

Question 23

Where to look on EKG for inferior MI? what shouldn’t be given to these patients?

Answer 23

• II, III, aVF
• suspect RV MI
• nitro

Question 24

if you suspect inferior/RV MI, what should you next do?

Answer 24

right sided EKG (V1R-V6R)

Question 25

Where to look on EKG for posterior MI? what vessel is impacted?

Answer 25

• ST depression in V1, V2, V3
• left circumflex

Question 26

what to do if you suspect posterior MI?

Answer 26

do V7-V9 under scapula on back so you can see ST elevation

Question 27

ST elevation in aVR is suggestive of?

Answer 27

occlusion of the L MCA

but does not demote MI finding if ST elevation elsewhere suggests it

Question 28

what is diffuse ST depression and aVR elevation concerning for?

Answer 28

LAD block

Question 29

EKG findings pericarditis

Answer 29

• diffuse ST eleation
• PR elevation in aVr

Question 30

EKG findings TCA overdose in aVR

Answer 30

• sinus tachy
• widened QRS complex

Question 31

new LBBB is concerning for?

Answer 31

STEMI