The patient has an irregular heart rhythm. To determine an accurate heart rate, the nurse first:

Question

a. identifies the markers on the ECG paper that indicate a 6-second strip.
b. counts the number of large boxes between two consecutive P waves.
c. counts the number of small boxes between two consecutive QRS complexes.
d. divides the number of complexes in a 6-second strip by 10.

Answer 1

A
Six-second method: A quick and easy estimate of heart rate can be accomplished by counting the number of P waves or QRS waves within a 6-second strip to obtain atrial and ventricular heart rates per minute. This is the optimal method for irregular rhythms. Identify the lines above the ECG paper that represent 6 seconds, and count the number of P waves within the lines; then add a zero (multiply by 10) to identify the atrial heart rate estimate for 1 minute. Next, identify the number of QRS waves in the 6-second strip and again add a zero to identify the ventricular rate. Large box method: In this method, two consecutive P and QRS waves are located. The number of large boxes between the highest points of two consecutive P waves is counted, and that number of large boxes is divided into 300 to determine the atrial rate in beats per minute. The number of large boxes between the highest points of two consecutive QRS waves is counted, and that number of large boxes is divided into 300 to determine the ventricular rate. This method is accurate only if the rhythm is regular.
Small box method: The small box method is used to calculate the exact rate of a regular rhythm. In this method, two consecutive P and QRS waves are located. The number of small boxes between the highest points of these consecutive P waves is counted, and that number is divided into 1500 to determine the atrial rate in beats per minute. The number of small boxes between the highest points of two consecutive QRS waves is counted, and that number is divided into 1500 to determine the ventricular rate. This method is accurate only if the rhythm is regular.