On an ECG when the ventricular heart rate is regular,the rate can be determined by counting the number of large squares between two consecutive QRS complexes then
A) dividing 300 by that number of large squares
B) dividing 200 by that number of large squares
C) dividing 400 by that number of large squares
D) dividing 600 by that number of large squares

Question

Quizplus · Accepted Answer

Dividing 300 by the number of large squares between two consecutive QRS complexes is a common method to estimate the heart rate on an ECG when the rhythm is regular. Each large square on the ECG paper represents 0.20 seconds, and since there are 5 large squares per second (1 second/0.20 seconds per large square = 5), and 60 seconds in a minute, the formula 300 (60 seconds x 5) divided by the number of large squares between QRS complexes gives an estimate of the heart rate per minute.

On an ECG When the Ventricular Heart Rate Is Regular,the