Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

LSS 1 > Cardiovascular Systems 10 - Electrocardiography > Flashcards

Cardiovascular Systems 10 - Electrocardiography Flashcards

1
Q

What is a lead in an ECG?

A

Leads are a view of the electrical activity of the heart, they are not a cable/wire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a vector?

A

A quantity that has both magnitude and direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe what can be deduced from the lines of the ECG, including steepness, direction and width of the deflection.

A
  • The isoelectric line is where there is no net change in voltage, as vectors are perpendicular to the lead
  • The steepness of the line shows the velocity of an action potential
  • The width of the deflection shows the duration
  • Upward deflections are towards the cathode (+) and downward are towards the anode (-)
  • Every wave has both up and downstrokes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the P wave?

A
  • The electrical signal that stimulates contraction of the atria
  • Generated by the sinoatrial node
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the QRS complex?

A
  • The electrical signal that stimulates contraction of the ventricles
  • Q is where the electrical signal is in bundle branches
  • R is where the signal is in purkinje fibres (early ventricular depolarisation)
  • S is also where the signal is in purkinje fibres (late ventricular depolarisation)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the T wave?

A

The electrical signal tat signifies relaxation of the ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is the electrical signal in the heart between the P wave and QRS complex?

A
  • It is in the atrioventricular node
  • It is isoelectric
  • AV node conducts slowly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What causes the line between the QRS complex and the T wave?

A

The signal is in the fully depolarised ventricles, it is isoelectric.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the placement of electrodes on a patient?

A
  • One on the right arm, one the left arm, right leg and left leg.
  • The other 6 (V1-V6) are on the ribs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where is the V1 electrode?

A

Right sternal border in the 4th intercostal space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where is the V2 electrode?

A

Left sternal border in the 4th intercostal space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where is the V3 electrode?

A

Halfway between V2 and V4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is the V4 electrode?

A

Mid-clavicular line in the 5th intercostal space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where is the V5 electrode?

A

Anterior axillary line at the level of V4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where is the V6 electrode?

A

Mid-axilliary line at the level of V4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is lead 1?

A

Right arm to left arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is lead II?

A

Right arm to left leg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is lead III?

A

Left arm to left leg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is heart rate calculated form an ECG?

A

300/number of big squares

20
Q

Which is bigger, T wave or P wave?

A

T wave

21
Q

How is the cardiac axis calculated?

A
  • Lead II and aVL are used, as they are 90 degrees apart
  • Amplitude fo LII is calculated, as it that of aVL. This is done by taking away the number of squares of the S from that of the R downward stroke of the QRS complex.
  • These are used as lines of a triangle
  • Trigonometry is used to find the hypothesis
  • 60-answer to find the angle of the heart (as the LII line is at an angle of 60 degrees)
22
Q

Which leads have a virtual anode?

A

aVR, aVL, aVF, V1-V6

23
Q

Which leads have a fixed anode?

A

LI, LII, LIII

24
Q

Which lead is the most commonly used single lead?

A

Lead II

25
Q

What is the normal range of the cardiac axis?

A

-30 to +90 degrees

26
Q

What is the approach used to take and analyse an ECG?

A
  • Ensure it is correct patient
  • Look at rate and rhythm
  • P-wave and PR interval
  • QRS duration
  • QRS axis
  • ST segment
  • QT interval
  • T wave
27
Q

Describe the ECG appearance in sinus bradycardia.

A
  • Each P wave is followed by QRS

- Rate is regular but slow

28
Q

What is the cause of sinus bradycardia?

A
  • Healthy
  • Caused by medication
  • Caused by vagal stimulation
29
Q

Describe the ECG appearance in sinus tachycardia.

A
  • P wave followed by QRS

- Regular rate but fast

30
Q

What causes sinus tachycardia?

A

Physiological response (secondary)

31
Q

Describe the ECG appearance in sinus arrhythmia.

A
  • Each P wave is followed by a QRS wave
  • Rate is irregular, but normal.
  • The R-R interval varies with breathing
32
Q

Describe the ECG appearance in atrial fibrillation.

A
  • Oscillating baseline, the atria contract asynchronously
  • Rhythm can be irregular, rate may be slow
  • Increased clot risk due to turbulent blood flow
33
Q

Describe the ECG appearance of atrial flutter.

A
  • Saw tooth pattern in the baseline of II, III, aVF
  • The atrial to ventricular beats at 2:1, 3:1 or higher ratio
  • The saw tooth is not always visible in all leads
34
Q

Describe the ECG appearance in first degree heart block.

A
  • Prolonged PR segment/interval due to slower AV conduction

- Regular rhythm, P wave before every QRS

35
Q

Describe the ECG appearance of second degree heart block (Mobitz 1)

A
  • Gradual prolongation of the PR interval until a beat is skipped
  • Most P waves followed by QRS, some are not
  • Regularly irregular (each component is regular, but the regularities are different)
36
Q

Describe the ECG appearance of second degree heart block (Mobitz II)

A
  • P waves are regular, but only some are followed by QRS
  • There is no PR prolongation
  • Regularly irregular, there is a ratio of successes to failures
37
Q

Describe the ECG appearance of third degree heart block.

A
  • P waves are regular, as are QRS, but there is no relationship
  • P waves can be hidden within QRS
  • There is non-sinus rhythm
38
Q

Which type of heart block is the most progressed?

A
  • Third degree heart block is complete
  • First degree is the most benign, it is a disease of aging
  • Second degree (Mobitz II) is more serious than Mobitz I, as it can rapidly deteriorate into third degree
39
Q

Describe the ECG appearance of ventricular tachycardia.

A
  • P waves are hidden
  • The rate is irregular and fast (100-200bpm)
  • High risk of fibrillation
  • This is a shockable rhythm
40
Q

Describe the ECG appearance of ventricular fibrillation.

A
  • Heart rate is irregular, 250bpm+

- The heart cannot generate an output- just lots of squiggly lines!

41
Q

Describe the ECG appearance of ST elevation

A
  • P waves are visible and always followed by QRS
  • Rhythm is regular and the rate is normal (85bpm)
  • The ST segment is elevated 2mm or more over the isoelectric line
42
Q

What causes ST elevation?

A

Infarction

43
Q

Describe the ECG appearance of ST depression.

A
  • P waves are visible, always followed by QRS
  • Rhythm is regular and heart rate is normal
  • The ST segment is depressed 2mm or more below the isoelectric line
44
Q

What causes ST depression?

A

Myocardial ischaemia (coronary insufficiency)

45
Q

What is the clinical relevance of ECG?

A
  • Cheap, reliable and fast way to assess heart function

- Can evaluate the conduction system and structure

LSS 1 (35 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions