If you did want an exact rateHeart Rate; calculated by counting the number of QRS complexes in six seconds and multiplying by 10; rate is also determined by measuring the number of large squares between two R waves; i.e. –1 large square = heart rate of 300/minute., you could count the number of millimeters across the R-R intervalThe distance between the top of the R waves. Figure 4.15 The Normal Q Wave and QT Interval Figure 4.15 illustrates the Q wave, QT interval and the R-R interval. A normal QT interval should be less than half the.... This is often accomplished with the use of calipers.
ECG paperAn ECG is a graphical display of electrical energy generated by the heart over time. ECG graph paper records this cardiac electrical activity, printing at a rate of 25 mm/second. The paper graph is divided into small 1 mm squares... records at a rate of 25mm/second which would total 1500 mm if allowed to print for a full minute (60 seconds x 25mm/second = 1500mm). Divide the total of 1500 by the R-R intervalA period measured on rhythm strip paper that measures a wave and a segment; the distance measured is equal to time taken as an ECG is voltage over time; a PR interval for example is measured from the beginning of... (in millimeters) to arrive at the number of QRSThe electrical representation of ventricular depolarization; the atrial repolarization is also a part of the QRS. ECG interpretation relies heavily on the QRS complex. The QRS complex represents the depolarization of the ventricles. The repolarization of the atria is also... complexes per minute.
Refer to the accompanying image to see the R-R interval is measured to be 19 mm.
1500 / 19 = 79 QRS complexes per minute
Heart RateThe number of QRS complexes per minute; note that HR may not equal perfused pulse rate. See also: - Step 1 Heart Rate - Rate - Rule of 300s (Triplicate Method) - Six Second Count - The Caliper Method 1.... = 79/minute
An earlier approximation using the triplicate method of 80/minute wasn’t far off the mark. Note that for regular rhythms (R-R interval is consistently the same), all three methods are effective in determining rate. For irregular rhythms with fluctuating R-R intervals, the six second countPerhaps the simplest and most common method to determine heart rates involves multiplying the number of QRS complexes found over six seconds by a factor of 10 to get the number of QRS complexes in a minute (60 seconds). Figure... is the only useful method for measuring heart rates.
1. Six Second ECG GuidebookA Practice Guide to Basic and 12 Lead ECG Interpretation, written by Tracy Barill, 2012 Introduction The ability to correctly interpret an electrocardiogram (ECG), be it a simple six second strip or a 12 lead ECG, is a vital skill... (2012), T Barill, p. 94