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Flashcards in Electrocardiography Deck (34):
1

describe pathway of limb lead I

between L and R arms

2

describe pathway of limb lead II

along the long axis of the heart, between L foot and R arm

3

describe pathway of limb lead III

between L foot and L arm

4

Which plane are the limb leads in?

frontal plane

5

Which plane are the augmented vector leads in?

frontal plane

6

Which plane are the precordial/chest leads in?

horizontal plane

7

Where are the electrodes placed for the standard limb leads?

L foot, L and R arms

8

Where are the electrodes placed for the augmented vector leads, and how does it work?

positive electrodes at L foot, L and R arms
negative central terminus calculated mathematically, near centre of heart

9

Where are the electrodes placed for the precordial/chest leads, and how does it work?

six positive electrodes placed: RA to apex, and around lateral left ribs
negative central terminus calculated mathematically, near centre of heart

10

electrical event associated with P wave

atrial depolarization

11

mechanical event occurring during P wave

end of diastasis

12

PR interval

less than 200 ms

13

electrical events associated with PR segment

atrial depolarization, impulse continues through the AV node, stops at Bundle of His

14

QRS interval

less than 100 ms

15

electrical event associated with the QRS complex

ventricular depolarization (bundle branches and Purkinje fibres)

16

component of ECG associated with bundle branch stimulation

QRS complex

17

component of ECG associated with atrial depolarization only

P wave

18

component of ECG associated with atrial contraction

PR segment

19

factors that affect QRS amplitude/height

directly related: muscle thickness
inversely related: body mass, pericardium (thickness and amount of fluid)

20

affect of body mass on QRS amplitude

larger body habitus = greater distance from electrodes = poor through-energy/muffled conduction

21

affect of pericardial effusion on QRS amplitude

more paricardial fluid = greater distance from electrodes = poor through-energy/muffled conduction

22

affect of thickened pericardium on QRS amplitude

poor through-energy/muffled conduction

23

affect of hypertrophic cardiomyopathy on QRS amplitude

more muscle = more impulses = more intensity

24

component of ECG associated with ventricular depolarization

QRS complex

25

component of ECG associated with Purkinje fibre stimulation

QRS complex

26

electrical event associated with the ST segment

ventricular electrical plateau before repolarization, and atrial repolarization

27

mechanical event occurring during QRS complex

atrial contraction (late filling)

28

electrical event associated with the T wave

ventricular repolarization and atrial resting phase

29

mechanical event occurring during ST segment

ventricular contraction

30

mechanical event occurring during T wave

end of ventricular contraction and IVRT

31

When does early filling occur on the ECG?

during the ventricular resting phase, in the electrical plateau between the T and the P waves

32

QT interval

less than 440 ms
(includes QRS and ST segments, QRS=100ms, systole=300ms)

33

ST interval

variable (though systole/ventricular contraction is about 300 ms)

34

Which lead is used to diagnose rhythms in most echocardiography labs?

limb lead II