Brainscape's Knowledge GenomeTM

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


See full index

BMD221 Biomedical Physiology > Week 2 ECG > Flashcards

Week 2 ECG Flashcards

1
Q

How are electrical signals of the heart detected

A
  1. Electrodes are placed on skin
  2. Machine records heart rhythm
  3. By recording waves of electrical activity
  4. Produces an ECG
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does an ECG measure

A

Effect on anatomical features of the heart
Not cell membrane potential
Shows PQRS wave

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

What does the PQRS wave show

A

Movement of an electrical wave across skin

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

P of PQRS

A

Atrial depol / contraction

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

QRS of PQRST

A

Bundle of His, purkinje fibres
Ventricular depol
Contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

T of PQRST

A

Ventricular relaxation / repolarisation

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

SAN relation to ECG

A
  1. Not seen much as there are not a lot of cells
  2. Also Not directional
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Atrial muscle relation to ECG

A

Takes up most of the P wave
- lots of muscle tissue
- depol = upward

  1. Steep opening of sodium channels ⬆️
  2. L type calcium ion channels open = plateau
  3. Calcium channels close, K+ continues to flow out
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

AVN relation to ECG

A

Small mass - seen at the end of the P wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Common bundle, branches and purkinje fibres + ECG

A

Not seen due to small area

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

Ventricular muscle relation to ECG

A
  • largest muscle mass
  • shows as PQRST complex
  • depolarisation + repolarisation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is happening at the level stage between S and T

A

L type calcium channels remain open for a long time

So there is no change = levelling on the ECG

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

What is happening during the T wave

A

Repolarisation but in the opposite direction

So is seen as upwards - the same as depol

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

What anatomical feature of the heart has the largest impact on the ECG

A

Ventricular muscle

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

What direction is an ECG

A

Too left to bottom right

^ affects how depol and repol are seen

  • depol is normally up, repol is down
    Reversed when going from bottom right to top left
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are segments on an ECG

A

Area between waves
1. PR
2. ST

17
Q

What are the two intervals on an EVG

A

PR and QT

Named from the first wave

18
Q

What is an atrioventricular block

A

Abnormal or absent conduction
So downstream tissue will not be excited by the travelling AP wave

19
Q

How is an AV block managed

A

Pacemaking tissue further along will generate its own APs

20
Q

Conduction in 1st degree AV blocks

A

Conduction through AVN is slowed but not interrupted

21
Q

P-QRS in 1st degree AV block

A

One P for every QRS (as normal)
But there is a longer gap
Of more than 200ms

22
Q

Conduction in 2nd degree AV block

A

Partially interrupted
But mostly proceeds

23
Q

P-QRS complexes in 2nd degree AV blocks

A

Several QRS complexes have no P wave

24
Q

Conduction in 3rd degree AV blocks

A

Conduction through the AVN is blocked

25
Q

P-QRS complexes in 3rd degree AV blocks

A

No correspondence
QRS complexes are very infrequent
Less than 40bpm

26
Q

Why is the PQRS complex irregular in 3rd degree AV block

A

Myogenic cells beyond the AVN produce their own APs

But at a much slower rate

So is not coordinated with the SAN

27
Q

What is Arrhythmia

A

Normal beating but SAN sends irregular signals

28
Q

What does arrhythmia look like on an ECG

A

Normal PQRS complex but is irregular

29
Q

Tachycardia

A

A very fast rhythm
Can apply to atria/ventricles/both

Very high rate = flutter

30
Q

What does tachycardia look like on an ECG

A

Complexes are normal and evenly spaced
But rate > 100bpm

31
Q

Bradycardia

A

Slow heart beat
Atria/ventricles/both

32
Q

What does bradycardia look like on an ECG

A

Complexes normal and evenly spaced but rate < 60 bpm

33
Q

What is fibrillation

A

One or both chambers locked in constant uncoordinated beating

34
Q

What does atrial fibrillation look like on an ECG

A

Baseline and ventricular response both irregular

35
Q

What does ventricular fibrillation look like on an ECG

A

Rapid wide irregular ventricular complexes

36
Q

What causes fibrillation

A

Re-entry - conducted wave circles back on itself

37
Q

What is wolf Parkinson white syndrome

A

A common re-entry
- occurs when the bundle of Kent (conductive tissue) crosses atrium to the ventricle

  • so signal passes along the ventricle
  • some parts contract before others
  • so there is no synchrony

BMD221 Biomedical Physiology (6 decks)

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