Brainscape's Knowledge GenomeTM

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


See full index

OSCE - skills > Approach to ECG > Flashcards

Approach to ECG Flashcards

1
Q

What are the first three steps of ECG interpretation?

A
  1. Rate
  2. Rhythm
  3. Axis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How would you calculate ventricular rate on an ECG?

A

Take the number of large squares on ECG paper in 1 minute (300) and divide by the number of squares between two sequential R waves

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

How would you assess rhythm?

A

Look at rhythm strip: lead II

Should be defined as regular, regularly irregular, or irregularly irregular

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

What does the axis represent in an ECG?

A

Since the left ventricle makes up most of the heart muscle under normal circumstances, normal cardiac axis is directed downward and slightly to the left:
Normal Axis = QRS axis between -30° and +90°.

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

How would you assess axis in an ECG?

A

Look at lead 1 and aVF (quadrant method)

  1. QRS wave should be positive (R wave should be more positive than S is negative)
  2. Should be done in lead 1 and aVF
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How would you assess the P wave?

A

Best seen in lead II

Should precede each QRS complex

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

What are P-wave abnormalities?

A
  1. P-mitrale – elongation of the P-wave (>120 ms) due to left atrial enlargement
  2. P-pulmonale – increased amplitude of the P-wave (>2.5 mm) due to right atrial enlargement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How would you assess the PR interval?

A

Should have a consistent duration

Shortening (<120 ms) suggests an accessory pathway bypassing the AV node

Elongation (>200 ms) suggests impaired AV conduction

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

What does PR shortening suggest?

A

An accessory pathway bypassing the AV node

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

What does PR elongation suggest?

A

Impaired AV conduction

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

How would you assess the QRS complex?

A

Normally consistent amplitude within leads

Elongation (>120 ms) suggests delayed conduction within the His bundle or Purkinje fibres

Increased amplitude suggests ventricular hypertrophy or abnormal ventricular conduction

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

What are causes of QRS elongation?

A
  1. Left bundle branch block
  2. Right bundle branch block
  3. Ventricular origin
  4. Idiopathic ventricular conduction delay
  5. Hyperkalaemia
  6. Ventricular paced rhythm
  7. Ventricular pre-excitation (WPW pattern)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How would you differentiate between left and right bundle branch block?

A

If the QRS complex is widened and downwardly deflected in lead V1, a left bundle branch block is present.

If the QRS complex is widened and upwardly deflected in lead V1, a right bundle branch block is present.

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

How would you assess the ST segment?

A

Should be isoelectric, elevation/depression suggests pathology

Pathological deviation usually presents in adjoining leads

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

What are causes of ST elevation?

A
  1. Infarction
  2. Pericarditis
  3. Bundle branch block
  4. LV aneurysm
  5. Brugada syndrome
  6. Benign early repolarization
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What artery do leads II, III and aVF represent?

A

Inferior

Right coronary artery

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

What artery do leads V1 and V2 represent?

A

Septal

Left coronary artery

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

What artery do leads V3 and V4 represent?

A

Anterior

Left anterior descending artery

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

What artery do leads V5, V6 and I represent?

A

Lateral

Left circumflex

20
Q

How would you assess the T-wave?

A

Should be positive in most leads

Normally negative in aVR and V1 (occasionally V2)

21
Q

In what leads could the T wave be negative (physiologically)?

A

aVR and V1

22
Q

How long is a normal PR interval?

A

12-200 ms

23
Q

How long is a normal QRS?

A

Narrow (<100 ms), normal amplitude

24
Q

What does inhalation do to heart rate?

A

Inhalation decreases vagal tone, increasing heart rate

25
Q

What does exhalation do to heart rate?

A

Exhalation increases vagal tone, decreasing heart rate

26
Q

What happens during blood pressure during inspiration?

A

Goes down

27
Q

What happens during blood pressure during expiration?

A

Goes up

28
Q

What are abnormal cardiac axes?

A

Left Axis Deviation = QRS axis less than -30°.
Right Axis Deviation = QRS axis greater than +90°.
Extreme Axis Deviation = QRS axis between -90° and 180°

See lead I as -90 to +90 (vertical half)
See lead aVF as 0 to 180 (horizontal half)

29
Q

If lead I is positive and aVF is negative, what is the deviation?

A

Possible Left Axis Deviation

30
Q

If lead I is negative and aVF is positive, what is the deviation?

A

Right Axis Deviation

31
Q

If lead I is negative and aVF is negative, what is the deviation?

A

Extreme Axis Deviation

32
Q

What are causes of Left Axis Deviation?

A

Left ventricular hypertrophy
Left bundle branch block
Inferior MI
Wolff-Parkinson-White Syndrome

33
Q

What are causes of Right Axis Deviation?

A 
Right ventricular hypertrophy
PE
Lateral STEMI
COPD
Hyperkalaemia
34
Q

What are causes of Extreme Axis Deviation?

A

Ventricular rhythms – e.g.VT, AIVR, ventricular ectopy
Hyperkalaemia
Severe right ventricular hypertrophy

35
Q

In what condition are p waves often absent?

A

Atrial fibrillation

36
Q

What are the normal durations of the interval in waves?

A

PR: 120-200 ms (3-5 small squares)
QRS: <120 ms
QT: <45ms in men; <47 ms in women

37
Q

What is a normal R wave amplitude in I, II and III?

A

< 20 ms

38
Q

What does an isolated Q wave in lead III present?

A

Respiration

39
Q

What are causes of pathological Q waves?

A

Left-sides pneumothorax
Dextrocardia
Perimyocarditis
Cardiomyopathy

40
Q

What are delta waves associated with?

A

WPW

Slurred upstroke of QRS complex

41
Q

What are tall T waves associated to?

A

Hyperkalaemia
Hyperacute STEMI

They are tall if - > 5mmin thelimb leadsAND
- > 10mmin thechest leads

42
Q

What causes biphasic T waves?

A

Ischaemia and hypokalaemia

43
Q

What causes U waves?

A

Hypothermia
Electrolyte imbalances
Antiarrythmic therapy (digoxin)

44
Q

How would diagnose first degree heart block on an ECG?

A

fixedprolongedPR interval (>200 ms)

45
Q

How would diagnose second degree (2.A) heart block on an ECG?

A

Progressive prolongation of the PR intervaluntil eventually the atrial impulse is not conducted and theQRS complex is dropped

AV conduction is picked up after

46
Q

How would diagnose second degree (2.B) heart block on an ECG?

A

Consistent PR interval durationwithintermittently dropped QRS complexesdue to a failure of conduction

The intermittent dropping of the QRS complexes typically follows arepeating cycleof every3rd (3:1 block)or4th (4:1 block)P wave.

47
Q

How would diagnose third degree heart block on an ECG?

A

No AV association

Narrow-complex escape rhythms(QRS complexes of <0.12 seconds duration) originateabove the bifurcationof thebundle of His

Broad-complex escape rhythms(QRS complexes >0.12 seconds duration) originate frombelow the bifurcation of the bundle of His

OSCE - skills (13 decks)

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