ECG Flashcards

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1
Q

What is the function of an Electrocardiogram?

A

Measures and records the electrical activity of the heart via electrodes placed on the skin in specific locations.

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2
Q

What are the waves recorded on?

A

International standard ECG paper

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3
Q

Name the 5 waves produced from the ECG

A

P, Q, R, S, T waves

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4
Q

What accounts for the P wave?

A

Atrial depolarization

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5
Q

What initiates atrial depolarization?

A

SA node

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6
Q

Why is the impulse delayed at the AV node after atrial depolarisation

A

Delay is caused by the slim AV node fibres which restricts the impulse from passing through freely

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7
Q

What component of the ECG is produced from this impulse delay

A

Isoelectric PR segment

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8
Q

Explain the QRS complex

A

Ventricular depolarization begins at the septum- left to right (Q), spreads to the apex (R), and the post part pf ventricular muscle (S).

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9
Q

What does the Isoelectric ST line indicate?

A

Ventricular depolarization is complete

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10
Q

Ventricular repolarization begins at the apex and results in which wave forming

A

T wave

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11
Q

Where is atrial repolarization

A

Wave is hidden as it takes place at the same time as ventricular depolarization which overshadows it.

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12
Q

What is the range of the duration and amplitude of a normal P wave?

A

Amplitude: 0.05mV-0.25mV
Duration: 0.06s-0.10s

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13
Q

What is the range for duration of the PR interval

A

0.12s - 0.20 s

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14
Q

What is the range of the duration and amplitude of a normal QRS complex?

A

Amplitude: 0.5- 3.0mV
Duration: 0.06-0.10s

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15
Q

What is the J point?

A

Start of the ST segment

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16
Q

What does the QT interval measure?

A

Measures time of ventricular depolarization and repolarization

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17
Q

What is the duration of the QT interval

A

0.36-0.44s

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18
Q

Which wave often goes unnoticed and what does it signify

A

U wave
Signifies the repolarization of papillary muscles/purkinje fibers

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19
Q

What do the small squares represent on duration and amplitude?

A

0.04sec in duration
0.1mV in amplitude

20
Q

Purpose of the Calibration mark?

A

Serves as a reference point on ECG tracing

21
Q

What is an Artifact?

A

Markings on ECG tracing that are not a product of heart’s electrical activity

22
Q

Examples of what could cause an artifact

A

Patient movement

23
Q

Normal value for the duration of P-R and Q-T interval

A

P-R: 0.12-0.20
Q-T: less than and equal to 0.44

24
Q

Which augmented lead readings is inverted on the graph

A

aVR

25
Q

Which lead is most often chosen as a rhythm strip?

A

Lead 2

26
Q

There are 9 steps used to interpret ECG’s; name them

A

Rate
Rhythm
P waves
QRS complexes
PR intervals
ST segments
T waves
QT intervals
U waves

27
Q

What is the average heart rate in adults

A

60 to 100 beats per minute

28
Q

Formula used to calculate heart rate

A

300/ # large boxes in R-R interval

29
Q

If number of boxes between R-R = 6. What is the heart rate?

A

50 bpm which suggest bradycardia

30
Q

How many successive R-R intervals should you check to determine regularity of the heart’s rhythm

A

2

31
Q

R-R intervlas at different distances apart signifies?

A

Irregular rhythm

32
Q

What are the steps to determine a normal sinus rhythm?

A

Step 1: Calculate heart rate
Step 2:Determine Regularity
Step 3: Assess the P waves
Step 4: Determine PR interval duration
Step 5: QRS duration

33
Q

What 2 vectors does the ECG compare

A

Heart vector- showing current flow on heart
Recording lead vector- with reference

34
Q

The ECG only looks at the charge on the outside of fibers, True or False?

A

True

34
Q

What do these vectors describe?

A

Depolarization and repolarization

35
Q

Vectors will always be positioned so that the head of the vector is in area of positive charge , True or False?

A

True

36
Q

Which lead has the biggest bulk of electrical activity?

A

Lead 2

37
Q

State Einthoven’s Law

A

In the ECG, at any given instant, the potential of any wave in lead 2 is equal to the sum of the potentials in lead 2 and lead 3

38
Q

Which leads does Einthoven’s Law use

A

Bipolar leads

39
Q

What creates the Hexaxial reference diagram?

A

Bipolar and Augmented leads

40
Q

What does a positive QRS in Leads 1 and 2 indicate

A

Heart axis is normal

41
Q

If lead 1 is negative deflection and lead 3 is a positive deflection, what is the axis

A

Right axis deviation

42
Q

If lead 1 has a positive deflection and lead 3 has a negative deflection, what is the axis

A

Left axis deviation

43
Q

If lead 1 has a positive deflection and lead 3 has a positive deflection then the axis is

A

Normal heart axis

44
Q

What does having a left axis deviation mean

A

Endomorph- short stature
Pregnancy
Left ventricle hypertrophy
Left bundle branch block

45
Q

What does Right axis deviations mean

A

Ectomorph- tall/thin
Hypertrophy of right ventricle
Right bundle branch block