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SS- Cardio > EKG > Flashcards

Flashcards in EKG Deck (49):
1

normal axis

I: up
aVF: up

2

left axis deviation

I: up
aVF: down

3

right axis deviation

I: down
aVF: up

4

extreme right axis deviation

I: down
aVF: down

5

Heart rate from EKG

300/ big boxes

6

duration of small box

40 msec

7

duration of big box

200 msec

8

inferior leads

II, III, aVF
right coronary artery
appearance: normal
(II: no S wave)

9

septal leads

V1, V2
left anterior descending artery
appearance: small P wave; upside down
(V2: upright T wave)

10

anterior leads

V3, V4
left anterior descending artery
appearance: small P wave, tall QRS and T
(V3: upside down QRS)

11

lateral leads

I, aVL, V5, V6
circumflex artery
appearance: small P waves

12

What is unique about lead aVR?

no Q wave

13

P wave

atrial depolarization/ contraction

14

QRS complex

ventricular depolarization/ contraction
atrial repolarization
less than 120ms

15

T wave

ventricular repolarization

16

QT interval

less than 1/2 R-R interval
beginning of Q to end of T wave
less than 440ms
ventricular depol and repol

17

ST segment

end of S wave to beginning of T wave

18

PR interval

beginning of P wave to R wave
less than 200ms

19

PR segment

end of P wave to beginning of Q wave
AV node conduction to Bundle of His

20

intraventricular conduction delay (IVCD)

widened QRS with no other abnormalities

21

RBBB

widened QRS with rabbit ears on V1 or V2 (big split)

22

LBBB

widened QRS with rabbit ears on lead V5 or V6
considered a STEMI if new

23

ventricular origin of beat

no P wave before widened QRS

24

ischemia

ST segment depression (2mm or 2 small boxes)
T wave inversion

25

injury

ST elevation (2mm or 2 small boxes)
T wave hypertrophy (tombstone)

26

infarction

significant Q waves (at least 1/3 size of QRS)

27

STEMI

ST segment elevation
severe if there is a giant Q wave

28

Wolf-Parkinson-White syndrome

short PR interval
direct pathway from SA node to ventricles: high HR
due to re-entry

29

What does a prolonged QT interval put a patient at risk for?

ventricular tachyarrhythmias
ex: torsades de pointe and v. fib

30

type 1 AV block

prolonged PR interval

31

type 3 AV block (complete heart block)

P waves and QRS complexes are not related to each other
Tx: pacemaker

32

type 2 AV block: Mobitz type I

increasing length of PR intervals leading to a dropped QRS
(going going gone)

33

type 2 AV block: Mobitz type II

normal PR interval leading to a dropped beat
risk for type 3 AV block

34

type 3 AV block (complete heart block)

P waves and QRS complexes are not related to each other

35

ventricular hypertrophy

increase voltage, can have inverted T wave (increases CAD risk)
delayed depolarization/repolarization

36

pericarditis

diffuse ST elevation in all leads

37

altered automaticity

myocyte fires that is not stimulated by SA node
can alter slope of depolarization: phase 4 pushed to threshold

38

triggered automaticity

AP "triggers" a 2nd AP immediately after it
delayed after-depolarization

39

Re-entry

unidirectional block in normally contiguous pathway(ex: from fibrosis or MI = now noncontiguous)
impulse takes a slower alternative pathway: moves anterograde and retrograde (normal pathway has had time to repolarize enough to trigger)
retrograde pathway sets up loop leading to ventricular tachycardia
HR: >140 and sustained

40

junctional rhythm

no P waves, constant firing of atria
seen in digitalis intoxication
due to enhanced automaticity

41

multifocal atrial tachycardia

constant firing from multiple sites in the atria: lots of EKG morphologies
see in emphysema due to high CO levels
due to enhanced automaticity

42

V-tach

due to organized re-entry
Tx: DC cardioconversion then maintain with Class I (slow conduction and increse refractory period) or III (prolong repol. and increase effective refractory period)

43

SVT

due to re-entry

44

arrhythmias due to enhanced automaticity

sinus tachycardia
atrial premature beat
ventricular premature beat

45

What might make a latent pacemaker prone to acceleration?

beta stimulation
hypokalemia
fiber stretch
hypoxemia
acidosis
injury

46

arrhythmias due to abnormal "triggered" automaticity

early after depolarization: interrupts phase 3 (can trigger long QT (torsades))
delayed after depolarization: interrupts phase 4 (occur as a result of Ca overload (digitalis))

47

ventricular bigeminy

due to digitalis (Ca overload)
exacerbated by: catecholamines, hypokalemia

48

torsades de pointes

polymorphic ventricular tachycardia triggered by EAD
occurs in QT prolongation (phase 2 and 3)
see in K channel blockers
exacerbated by: low HR, hypokalemia
re-entry

49

arrhythmias due to re-entry

atrium: a. fib/flutter
AV node: PSVT
ventricle: ventricular tachycardia/fibrillation
Drugs treat by interrupting re-entry: change conduction velocity, refractory period, convert unidirectional block to complete block