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Flashcards in Axis and BBB Deck (67)
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1

The QRS complex is indicative of what within the heart?

deolarization of the ventricles

2

What is the normal order of depolarization within the heart?

septum (L to R)
Main portion of ventricle (largest vector)
Basilar/bottom portion of ventricle

3

What leads are in the frontal plane?

limb leads

4

What leads are in the transverse (coronal) plane?

precordial leads

5

What is amplitude affected by?

the size and direction of vectors in relation to lead

6

What happens to amplitude with hypertrophy?

There is more heart, thus more vector, thus more amp

7

What happens to amplitude with infarct?

Dead hear cells, thus less heart, less of a vector and thus decreased amp

8

What are the criteria for low voltage?

<10mm in all precordial leads

9

What is a big determinant in voltage?

the amount and location of fluid and fat

10

How is voltage affected with a pericardial effusion?

decreased

11

What is the normal duration of QRS?

<.12 sec, 3 small boxes

12

How do we measure QRS?

measure it in several different leads and use the widest one

13

What are some causes of wide QRS?

hyperkalemia (wide and peaked T waves)
medications
ventricular tachy
idioventricular rhythms
WPW
BBB and IVCD
ventricular premature contractions
aberrrantly conducted complexes
pacemaker

14

Where is QRS notching most common?

precodial leads

15

What is QRS notching usually indicative of?

generally a/w benign causes of ST elevation
early repol
pericarditis

16

What is an Osborn Wave?

large deflection at the end of QRS complex (much larger than benign notching)

17

Where do we see Osborn waves?

Severe hypothermia

18

How do we determine if a Q wave is benign or pathologic?

based on size

19

What can cause a slight variation in the depth of a Q wave with respiration

obeses, pregnant or ascites

20

What are the characteristics of a pathological Q wave?

> 1/3 total height of QRS
> 0.04 seconds wide (one small box)
Look at regional pattern (inferior, anterior, lateral)

21

What is normal transitional pattern?

mostly neg to mostly pos in precordial leads

22

Where is the transition zone?

V3-V4

23

What happens if the transition zone is before V3?

axis is rotated counterclockwise = early rotation

24

What happens if the transition zone is after V4?

axis is rotated clockwise = late rotation

25

How do we measure the QT interval?

beginning of QRS to the end of T wave

26

What is a normal QT interval?

less than 1/2 R-R interval

27

What are multiple variables that affect QT interval?

age, HR, meds, etc

28

What is indicative of a prolonged QT?

Torsades

29

What is the definition of the electrical axis?

sum of all vectors of individual ventricular myocytes

30

What is the normal average direction of the hearts electrical axis?

down and to the left