ECGs

Question 1

At what degree is the normal cardiac axis?

Which direction do the QRS complexes point to in leads I, II, III and aVF?

Answer 1

Between -30 and +90 degrees

I = mainly +ve
II = most +ve
III = mainly +ve
aVF = mainly +ve

Question 2

At what degree does the heart depolarise in right axis deviation?

Which direction do the QRS complexes point to in leads I, II, III and aVF?

Answer 2

RAD occurs at greater than +90 degrees

I = mainly -ve
II = mainly +ve
III = mainly +ve 
aVF = +ve

Question 3

At what degree does the heart depolarise in left axis deviation?

Which direction do the QRS complexes point to in leads I, II, III and aVF?

Answer 3

LAD occurs at less than -30 degrees

I = mainly +ve
II = mainly -ve
III = mainly -ve
aVF = mainly -ve

Question 4

What do these p waves abnormalities indicate:

1. Absent with irregular rhythm?
2. Chaotic baseline?
3. Sawtooth baseline?
4. Flat line?

Answer 4

1. atrial fibrillation
2. atrial fibrillation
3. atrial flutter
4. no atrial activity