01 - Cardiac Phys and EKG Flashcards Preview

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Flashcards in 01 - Cardiac Phys and EKG Deck (43):
0

The heart has electrical activity known as

Action potentials

1

EKG is the recording of the hearts

Electrical activity

2

The heart acts as a _____ that generates electrical currents that can be measured on the

Pump
Skin surface

3

Pulmonary circulation is a ____ resistance and pressure system

Low
25/10 mmHg

4

Systemic circulation is a ____ resistance and pressure system

High
120/80 mmHg

5

Review charts

Do that

6

Three types of cardiac cells

Pacemaker - electrical power source
Electrical conducting - hard wiring
Myocardial - contractile machinery

7

At rest, the Vm of pacemaker cells is

Constant
Both the inside and outside of the cell are at constant potential

8

How big is a cardiac pacemaker cell?

5-10 um

9

During an action potential, Vm of a pacemaker cell is

Not constant
Current is flowing
Inside and outside are not constant

10

An action potential propagating away from the positive EKG lead produces what kind of signal?

Negative
AP produces positive signal when propagating toward positive lead

11

Rapid depolarization correlates to

Sodium influx

12

At the plateau, there is calcium

Influx

13

During repolarization, there is a

Potassium EFFLUX

14

What are the pacemakers of the heart?

SA and AV node

15

Which is the dominant pacemaker of the heart? What is it's rate of impulse?

SA node
60-100 bum

16

How big are myocardial cells?

50-100 um

17

The magnitude and polarity of an EKG signal depends on

Depolarizing or repolarizing
Position and orientation of electrodes

18

When depolarization begins, it generates a ______ deflection

Positive
The EKG returns to baseline when the pos and neg charges are balanced

19

The negative deflection is formed when the wave of polarization

Recedes from the electrode
The fully depolarized cell causes the ECG to return to baseline

20

The effects of repolarization are similar to that of depolarization except that the charges are

Reversed

21

The placement of bipolar limb leads on the three lead EKG is known as

Einthoven Triangle

22

Augmented voltage leads (aV) utilize one bipolar limb electrode as _____, and the other two as a _______ negative lead

Positive
Combined

23

Describe the unipolar limb leads: aVR aVL aVF

aVR - right arm positive, left arm and leg negative
aVL- left arm positive, right arm and left leg negative
aVF - left foot positive, arms negative

24

Lead II yields the most information about

Ischemia in the left ventricle and septum; arrhythmias in the right atrium

25

Position of lead I

0

26

Position of lead II

60

27

Position of lead III

120

28

Position of aVL

-30

29

Position of aVR

-150

30

Position of aVF

90

31

The chest leads v1-v6 (precordial) are positioned in successive steps at

Right margin of the sternum to the left edge of the thorax

32

If v1 through v6 are imagined to be spokes of wheel, their horizontal plane cuts the body into

Top and bottom halves

Oh ok

33

This lead produces a mostly negative deflection

V1

34

This lead describes a straight line directly from the patients back through the anterior aspect of the chest

V2

35

What is the common wall shared by the right and left ventricles? What runs through this wall?

Interventricular septum
Right and left bundle branches

36

Which leads best describe conduction abnormalities of the bundle branches?

V3 and V4

37

What are leads V5 and V6 referred to as?

Left chest leads
They are oriented along the left axiliary lines

38

This six limb leads can be modified limb leads represented by which four trunk leads?

V1-V4
So that all leads can be placed on the trunk of the body

39

Six clinical uses of the EKG?

Detection of arrhythmias and cardiac abnormalities
Indication of myocardial damage
Detection of electrolyte disturbances
Screening tool for diagnosis of ischemic disease
Can indicate anatomic and physiological state of the heart
Diagnose some noncardiac pathology

40

Depolarization moves from the linings (endocardium) of the ventricular cavity _______ to the epicardial surface of the ventricle

Outward

41

The only conducting path between the atrium and ventricle is?

AV node

42

When depolarization reaches the myocardial cell, calcium released causes the cell to contract. What is this process called?

Excitation contraction coupling