MI Flashcards Preview

Cardio Pulm > MI > Flashcards

Flashcards in MI Deck (45):
1

Best Discriminator of MI w/n 3 hours of chest pain onset

EKG

2

Transmural MI, injury and myocardial ischemia

-full thickness
-usually L ventricle 2* to coronary artery disease

3

MI diagnosis

At least 2 of 3:
-symptoms >20min
-EKG changes (at least 2 leads)
-Enzyme changes

4

ST Segment Elevation
>6 months =

ventricular aneurysm

5

After 3 hours best discriminant of MI is

creatine kinase MB

6

Reciprocal EKG changes

-indicative of large MI
-in leads opposite of TM MI
-change is transient
-ST segment depression with T wave upright

7

Myocardial Ischemia

-Zone of Ischemia: functioning tissue at periphery of infarct
-T wave increased size & peaked & symmetrical for 1st several hours
-T wave inverts after 24-48 hours
-After 1st week T gets upright

8

Myocardial Injury

Zone of Injury: nonfunctional area around infarct
-indicates acute MI
-ST Elevation >1mm
-ST segment normal by 72 hours

9

Myocardial Infarct

Zone of necrosis: irreversible damage at center of MI
-significant Q wave >0.04 sec (any lead but III & aVr)
-w/n 48 hours & never go away

10

EKG with MI

-Significant Q wave (>0.04 sec)
-occur w/n 48 hours
-never goes away

11

EKG with Myocardial Ischemia

-incr T wave; peaked and symmetrical
-initially & for 1st several hours
-24-48 hours after MI: T wave inverts
-becomes upright after 1st week

12

EKG with Myocardial Injury

-ST segment elevation
->1mm over baseline (2 small boxes)
-immediately
-returned to normal by 72 hours

13

Potassium

resting membrane potential

14

Calcium

threshold potential

15

Low K+

-membrane potential lower

16

High K+

-membrane potential higher

17

Low Ca++

-threshold potential lower

18

High Ca++

-threshold potential higher

19

Trousseau sign

-(hypocalcemia)
-contraction of hand and fingers with the arterial blood flow of arm occluded for 5 min

20

Chvostek Sign

-hypocalcemia
-tap facial nerve below temple and nose/lip twitches

21

EKG with subendocardial MI

-ST segment depression
-Inverted T wave (deep and symmetrical)

22

Normal Magnesium Levels

-1.8-3.0 mg/dL

1.5-2.5 mEq/L

23

Hypomagnesia

-alcoholics or result of multiple electrolyte abnormalities
-can lead to myocardial irritability, A-fib, PVC

24

Subendocardial MI

(Non-Q wave MI)
-partial thickness (inner portion)
-necrosis is patchy
-due to relative insufficiency of coronary blood flow
-ST seg depression
-Inverted T waves

25

ST Segment depression

-Occurs with subencdocardial MI, K+ deficiency, digitalis toxicity with ex's (if ischemic)

26

Normal K+ levels

3.5-5.3 mEq/L

27

Normal Ca++ Levels

-8.2-10.4 mg/dL

4.5-5.5 mEq/L

28

Hypercalcemia

-raises threshold potential (decreased excitability)
-EKG: shortened QRS, depressed T waves

-->heart block

29

Hypocalcemia

-lowers threshold potential (easier to excite)
-EKG: prolonged QT interval

-->ventricular arrhythmia & cardiac arrest

30

Causes of Hypercalcemia

-thiazide diuretic use
-acidosis
-adrenal insufficiency
-immobility
-vitamin D excess

31

Causes of Hyperkalemia

-endocrine problems
-renal problems
-result of K+ replacement/overdose

32

Causes of Hypokalemia

-use of diuretics
-vomiting
-diarrhea
-sweating
-alkalosis

33

Causes of Hypocalcemia

-multiple transfusion of titrated blood
-renal failure
-alkalosis
-laxatives
-antacid abuse
-parathyroid damage/removal

34

Hyperkalemia

-cell membrane hypopolarized (easier to stim)
-EKG: narrow, tall T waves, shorter QT interval
-EKG severe: ST seg depression, prolonged PR, wide QRS

-->v fib or cardiac arrest

35

Hypokalemia

-cell membrane becomes hyperpolarized (harder to excite)
-EKG: decr T wave amplitude, ST seg depression, P wave peaked, QRS prolonged

-->ventricular arrhythmias

36

Symptoms of Hypercalcemia

-fatigue
-weakness
-lethargy
-anorexia
-impaired renal function
-nausea
-constipation

37

Symptoms of Hypocalcemia

-confusion
-paresthesia (mouth, digits)
-Carpal spasm
-hyperreflexia

38

Anterior Infarct

V2, V3 (V4 with greater damage)

Blood Supply: LAD

39

Anteroseptal Infarct

V1, V2, V3

Blood Supply: LAD

40

Anterolateral Infarct

-V4, V5, V6, I, aVL

Blood: LAD & Circumflex

41

Septal Infarct

-Leads V1, V2

Blood: LAD

42

Lateral Infarct

I, aVL, V5, V6

Blood: circumflex

43

Inferior Infarct

II, III, aVF

Blood: RCA

44

Inferolateral Infarct

-II, III, aVF, V5, V6

Blood: RCA & Circumflex

45

Posterior Infarct

V1, V2, V3

Blood: posterior descending