Brainscape's Knowledge GenomeTM

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


See full index

Life Support Systems (LSS) > ECG and Thoracic Ultrasounds > Flashcards

ECG and Thoracic Ultrasounds Flashcards

1
Q

What do different parts of an ECG lead correspond to?

A

P wave is atrial depolarisation.
QRS is due to ventricular depolarisation (this masks atrial repolarisation).
T wave is ventricular repolarisation.

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

What is a U wave?

A

An extra wave sometimes observed after a T wave. It’s thought to be due to repolarisation of the papillary muscles. If a U wave follows a normally shaped T wave, it can be assumed to be normal. If it follows a flattened T wave, it may be pathological.

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

What is a normal PR interval?

A

120-200ms.

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

What does a short PR interval suggest?

A

The atria have depolarised from close to the AV node. or there is abnormally fast conduction from the atria to the ventricles.

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

What does the length of the QRS complex show?

A

How long it takes for depolarisation to spread through the ventricles.

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

What is a normal length for a QRS complex?

A

120ms or less.

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

When does ventricular contraction proceed?

A

In the ST segment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What length is often considered prolonged for a QT interval?

A

> 450ms

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

What does the six V-leads look at?

A

V1 and V2 look at the right ventricle (anteroseptal). V3 and V4 look at the septum between the ventricles and anterior wall of the left ventricle. V5 and V6 look at the anterior and lateral walls of the left ventricle.

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

Which lead is used to identify cardiac rhythm?

A

The one which shows the P wave most clearly, usually lead II.

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

What does an equal sized R and S wave represent?

A

The depolarisation is moving at right angles to the lead.

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

What does a predominately downward QRS complex (S is greater than R) show?

A

The depolarisation is moving away from that lead.

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

What is the cardiac axis?

A

The average direction of spread of the depolarisation wave through the ventricles as seen from the front.

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

What are the angles of leads I, II, aVF and aVL?

A

0, 60, 90 and -30 respectively.

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

Which lead is opposite to lead II?

A

aVR

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

Which structure do leads I and aVL look at?

A

The lateral left surface of the heart.

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

Which lead(s) look at the inferior surface of the heart?

A

Leads II, III and aVF.

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

Which lead(s) look at the right atrium?

A

aVR

19
Q

Why does right ventricle hypertrophy lead to right axis deviation?

A

The hypertrophied ventricle has more of an effect on the QRS complex than the left ventricle, so the average depolarisation wave swings towards the right.

20
Q

When is a left axis deviation significant?

A

Once the QRS deflection is predominately negative in lead II.

21
Q

What is the electrode attached to the right leg for?

A

It is an Earth and doesn’t contribute to any leads.

22
Q

If the QRS deflection in lead I is negative, what does it suggest?

A

A right axis deviation.

23
Q

Which way does the septum depolarise?

A

From left to right.

24
Q

What is sinus arrhythmia?

A

Rate is irregular (variable R-R intervals).

25
Q

What is a normal resting heart rate, for an average person?

A

60-100 beats per minute.

26
Q

Describe atrial fibrillation.

A

An oscillating baseline due to atria contracting asynchronously.
Rhythm can be irregular, and rate may be slow.
Turbulent flow pattern increases clot risk.

27
Q

Describe atrial flutter.

A

A regular saw-tooth pattern in baseline (visible on II, III and aVF). Atrial to ventricular beats at a 2:1 ratio or higher.

28
Q

Describe first degree heart block.

A

Prolonged PR interval, caused by slower AV conduction. Regular rhythm with 1:1 ratio of P-waves to QRS complexes.

29
Q

Describe second degree heart block (Mobitz I).

A

Gradual prolongation of the PR interval until beat skipped. Most P-waves followed by QRS, but some aren’t.
Regularly irregular. Caused by diseased AV node.

30
Q

Describe second degree heart block (Mobitz II).

A

P-waves are regular, but only some are followed by QRS. No PR interval prolongation.
Regularly irregular: success to failure 2:1.
Can rapidly deteriorate into 3rd degree heart block.

31
Q

Describe third degree heart block.

A

P waves and QRS complexes are regular, but no relationship.

Completely non-sinus rhythm.

32
Q

Describe ventricular tachycardia.

A

Rate regular and fast (100-200bpm).
P waves hidden by dissociated atrial rhythm.
SHOCKABLE.

33
Q

Describe ventricular fibrillation (cardiac arrest).

A

Heat rate irregular and 250bpm+.
Heart unable to generate an output.
SHOCKABLE

34
Q

Describe ST elevation.

A

Rhythm regular and rate normal. P wave always followed by QRS complex.
ST segment elevated > 2mm above isoelectric line.
Caused by infarction (tissue death due to hypoperfusion).

35
Q

Describe ST depression.

A

Rhythm regular and rate normal. P wave always followed by QRS complex.
ST segment depressed >2mm below isoelectric line.
Caused by myocardial ischaemia (coronary insufficiency).

36
Q

Give the types of B-mode transducers.

A

Low resolution ultrasound transducer. 3.5MHz but with increased depth of view due to curved array.
High resolution UT. 7-12MHz. Reduced depth of view (linear array).

37
Q

What is the gliding pleura (sliding lung) sign?

A

Produced in breathing as visceral pleura slides over stationary parietal pleura. Moves more basally rather than apically.

38
Q

What do artefacts beyond the echogenic pleural line indicate?

A

Healthy lung tissue filled with air.

39
Q

What are comet tails/ B-line artefacts?

A

Artefacts perpendicular to lung edge due to interlobular septa.

40
Q

What is the name of the sign looked for in an A-scan?

M-mode

A

Sea-shore sign.

41
Q

Which is the most useful view in a thoracic ultrasound?

A

Paracoronal/parasagittal plane as it eliminates rib artefact.

42
Q

How does fluid look on an US?

A

Completely black.

43
Q

What can thoracic ultrasound be used for?

A

Calculate the total amount of pleural fluid.
Detect pleural effusion and guide drainage.
Guide pleura and lung biopsy.
Identify pneumothorax.
Assess respiratory muscle function.

44
Q

What is a forced inspiration (“sniff”) test?

A

Tests the function of the phrenic nerve.
Assess the movement of the diaphragm. A rapid caudal movement is expected.
Abnormal: paradoxical cranial movement.

Life Support Systems (LSS) (6 decks)

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