The number of QRS complexes per minute; note that 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.... may not equal perfused pulse rateHeart rate is not always the same as pulse. Heart rate is a measurement of electrical activity while pulse ensures the perfusion of the blood to the target tissues. Many have been caught depending on the cardiac monitor for vital....
With ECGElectrocardiogram; also called an EKG; a representation of electrical voltage measured across the chest over a period of time. 1. Six Second ECG Guidebook (2012), T Barill, p. 196 monitoring, changes in heart 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. (HR) bear careful attention. This is the first step of the Six Second ECG 3-step method.
A person’s HR is usually identical to a person’s pulse rate. Heart rate is electrically identified. A pulse rate is felt i.e. pulse check, pulse oximetry, arterial monitoring. Not all electrical activity is reflected in a pulse, so determining a pulse rate is key as well.
Heart rate (and pulse rate) are determined by a number of factors. For healthy people, a HR is typically a result of Vagus nerve effects (slows the heart rate at the SA and AV nodeIs located in the inferior aspect of the right atria; functions to slow the conduction speed to allow for atrial conduction prior to ventricular conduction (atrial kick); also serves as a pacemaker if the SA node fails to fire. The...) and the amount of catecholamine release (epinephrine increases HR via the beta one effect). As a HR increases, considering ‘why epi?’ helps us keep a clear picture of normal physiology (a person’s up walking, anxious) or signs of possible pathophysiology (fever, loss of blood volume, abnormal blood distribution – anaphylaxis, septic shockSigns and symptoms of shock include shortness of breath, chest pain, hypotension, and an altered level of consciousness (due to hemodynamic compromise). As a general rule, a patient with a heart rate that is too fast (>150/minute - not enough... – toxicity and many others).
Three methods to determine HR are available:
– Six Second Method: within 6 seconds, count the number of QRS complexes and multiply by 10 to get QRS complexes per minute (HR); this method is ideal for slower rates and when the rhythm patternAn ECG rhythm that is initiated by one of several intrinsic pacemaker sites of a heart will often generate a regular, even rhythm pattern. This can also be referred to as a regularly regular rhythm. For regular rhythms, sometimes the... is irregular.
– Rule of 300sThe Rule of 300s (also known as the triplicate method) is useful for measuring heart rate over shorter periods (less than 3 seconds) or for calculating heart rates of rapid tachycardias. This method is quick but not quite as accurate...: after identifying an R waveFollowing the depolarization of the interventricular septum, ventricular depolarization then progresses from the endocardium through to the epicardium across both ventricles producing an R wave and an S wave. An R wave is the first positive deflection of the QRS... resting on a thicker grid line, divide the number of thicker lines to the next QRS to determine an approximate HR. 1, 2, 3, 4, 5, 6 lines separating the QRS complexes equate to rates of 300, 150, 100, 75, 60, 50 respectively.
– Rule of 1500: if a rhythmOften refers to a discernible pattern in time or distance between QRS complexes and/or P waves. is regular, measure the number of small mm squares of an 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.... Divide this number into 1500. Round off the result. i.e 1500/19mm R-R = 78.95 – best said as a heart rate of 79 (80/min would be close enough as well for clinical purposes).
A special case of the disparity between heart rate and pulse can occur with ventricular bigeminyVentricular bigeminy is named after premature ventricular complexes (PVCs) that happen every second beat. This can happen with alternating sinus or junctional complexes so it is good practice to mention the underlying rhythm as well. The PVCs with ventricular bigeminy.... Ventricular bigeminy is a cardiac rhythm with PVCs every alternate QRS complexThe 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.... Because PVCs are often without a corresponding peripheral pulse, the pulse rate would be equal to 1/2 the heart rate displayed on most cardiac monitors. A seemingly adequate heart rate of 70/minute may have a pulse of only 35/minute!
The patient – not the monitor – is the gold standard.
This cannot be said enough. Most of us have been caught at one time or another relying on the cardiac monitor to the exclusion and great risk of the patient. Heart rate is virtually always provided on the screen of a cardiac monitor. This number may offer some value but taking a patient’s pulse is always good practice. Don’t get burned.
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. 30, 91, 106, 107, 197