ECGs

Question 1

What are the leads of an ECG?

Answer 1

10 electrodes —> 12 lead recording
- limb leads —> coronal view
- AVR on left wrist
- AVL on right wrist
- N on right ankle
- AVF on left ankle
- chest leads —> axial view
- V1 —> 4th right ICS
- V2 —> 4th left ICS
- V3 —> between V2 and V4
- V4, V5, V6, —> 5th left ICS
- use lead II

Question 2

How does atrial fibrillation present on an ECG?

Answer 2

Loss of p-wave

Question 2

How does atrial flutter present on an ECG?

Answer 2

Saw-tooth patters

Question 3

How does axis deviation present on an ECG?

Answer 3

Axis Deviation = change in heart position/electrical
conduction (normal —> -30 to +90°)
- Right —> QRS between +90 and +180°
- lead III looks normal
- inverted lead I, inverted lead II
- Left —> QRS between -30 and -90°
- lead I looks normal
- inverted lead II, inverted lead III

Question 4

How does 1st degree heart block present on an ECG?

Answer 4

Long PR interval

Question 5

How does 2nd degree heart block present on an ECG?

Answer 5

Missing QRS complexes

Question 6

How does 3rd degree heart block present on an ECG?

Answer 6

No QRS complexes

Question 7

How do you calculate heart rate from an ECG?

Answer 7

300/no. large squares
- small square —> 40ms

Question 8

How do you calculate wave durations from an ECG?

Answer 8

300/large squares

Question 9

How does STEMI present on an ECG?

Answer 9

ST-elevation

Question 10

How does Wolff-Parkinson White present on an ECG?

Answer 10

δ-wave of QRS complex (QR elevation)
Biphasic T-wave