ECG

Question 1

what do the squares mean on an ECG?

Answer 1

small square = 40ms
large square = 200ms

Question 2

how do you calculate heart rate from an ECG?

Answer 2

1) 300 divided by number of large squares in one R-R interval

2) Number of QRS complexes x 6

Question 3

what is a normal PR interval?

Answer 3

120-200ms (3-5 small squares)

Question 4

what does a prolonged PR interval (>200ms/5 small squares) reflect?

Answer 4

AV block