Usually, the first word of a rhythmOften refers to a discernible pattern in time or distance between QRS complexes and/or P waves. is the location of the initiating impulse. This is followed by a descriptor of the 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. – bradycardiaA heart rate slower than a pacemaker’s regular intrinsic rate – commonly thought as less than 60/minute for sinus rhythms; less than 40/minute for junctional rhythms. The term ‘bradycardia’ describes a heart rate less than the normal rate expected of..., tachycardiaA cardiac rhythm with a rate above 100/minute; for example, if the impulse originates from the atria with a rate of 160/minute, the rhythm is called an atrial tachycardia. A cardiac rhythm is usually named first by the location of... or just label it a rhythm. Next, include any abnormal findings i.e. premature complexes or other abnormal ECG componentsAn ECG is composed of a series of waves and lines usually ordered into some repeatable pattern. The waves and lines are displayed on either a two dimensional screen or on ECG paper. The height of the tracing represents millivolts.... A rhythm might be called a sinus tachycardia with a premature ventricular complexA wide QRS complex that arrives early is called a premature ventricular complex (PVC). A PVC has a width of 0.12 seconds or longer. The elongated period of ventricular depolarization is caused by an abnormal, less efficient pathway of ventricular... (PVC). Sounds impressive, but the naming method is simple.
A few naming conventions require mentioning before examining the 3-step method in detail. A cardiac rhythm is usually named first by the location of the originating impulse. For example, rhythms that begin in the SA nodeThe SA node, usually the dominant pacemaker, is located in the right atrium at the opening of the superior vena cava. The SA (sinoatrial) node is a clump of hundreds of specialized cardiac cells that have the ability to self-initiate... are called sinus rhythms.
Rhythms that originate from the AV junctionConducts the impulse through the fibrous plate that separates the atria and the ventricles; consists of the AV node and the bundle of His; functions also to slow the conduction speed to allow for atrial conduction prior to ventricular conduction... are called junctional rhythmsA cardiac rhythm that occurs as a backup pacemaker when the sinus node fails to initiate an impulse; the junction typically fires at 40-60/minute; the P wave is either absent or inverted. A cardiac rhythm is usually named first by.... As the sample rhythm in Figure 5.1 on the previous page indicates, ventricular rhythms originate in the ventricle.
After first identifying the location of the generated impulse, then classify it according to rate. A rate faster than 100/minute (101/minute or faster) is a tachycardia. The term bradycardia applies to rhythms that are slower than the expected pacemakerAn electronic pulse generator that stimulates depolarization of the atria and/or the ventricles. 1. Six Second ECG Guidebook (2012), T Barill, p. 201 rate range (see Table 5.1). Rates that are neither fast nor slow are often labelled rhythms i.e. sinus rhythmAlso known as regular sinus rhythm or sinus rhythm, this cardiac rhythm is not a dysrhythmia; sinus rhythm originates in the sinoatrial (SA) node with a rate of 60-100/minute; P waves are upright in most leads and the QRS is....
For example, a rhythm originating from the SA node with a 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.... less than 60/minute, is labelled a sinus bradycardia. A rhythm that originates from the SA node at a rate above 100/minute is called a sinus tachycardia. A rhythm that originates from the SA node at a rate of 60-100/minute is just called a sinus rhythm. Similarly, a rhythm originating from the AV junctionConnects the atria to the ventricle and slows the impulse conduction speed sufficiently to allow for atrial kick; the junction consists of the AV node and the bundle of His; the junction is a supraventricular structure. 1. Six Second ECG... with a rate of 46/minute is a junctional rhythm – not a junctional bradycardiaA cardiac rhythm that occurs as a backup pacemaker when the sinus node fails to initiate an impulse; the junction typically fires at 40-60/minute; the P wave is either absent or inverted. When the heart rate drops below 40/minute then... – because a junctional rate is expected within this rate range.
Lastly, follow up with descriptors of any other noteworthy characteristics of the rhythm. Begin with any abnormalities of the underlying main rhythm. Is there ST deviationWhile ST deviations may be a normal occurrence for a subset of the population, most often ST deviation is a sign of either myocardial ischemia, myocardial infarction and/or cardiac disease. It makes sense, then, to report any finding of ST...? T wave inversionAn inverted T wave can point to cardiac ischemia among other causes. Ischemia to the epicardium prolongs ventricular repolarization to this area. This extended repolarization of the epicardium removes the delay between the repolarization of the endocardium and the repolarization...? Prominent Q waves? Complete labelling the rhythm by addressing any extra beats. Are there any premature beats?
Take an 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 with a heart rate of 52/minute, narrow QRS complexes, inverted P wavesA wave generated from the depolarization of the atria; the P wave is upright when originating from the SA node. The P wave represents the depolarization of the right and left atria. The P wave begins with the first deviation..., ST elevationThe upward placement of the ST segment greater than 1 mm from the isoelectric line; suggestive of cardiac infarction or ischemia. Between the QRS complex and the T wave, lies the ST segment. The ST segment usually follows the isoelectric... and an extra premature beat that has a wide 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.... How would this rhythm be labelled? First, narrow QRS complexes with accompanying inverted P waves point to a supraventricular rhythmIf the QRS is narrow, the rhythm originates from a supraventricular site. Otherwise, if the QRS is wide, chances are, the rhythm is a ventricular rhythm. Remember that the ECG is a two dimensional plotting of voltage (height or amplitude)... originating from the AV junction. The premature beat with a wide QRS complexA collection of waveforms (i.e. QRS complex and the ECG complex). 1. Six Second ECG Guidebook (2012), T Barill, p. 194 suggests a premature ventricular complex (PVC). The rhythm is then labelled a junctional rhythm with ST elevation and one PVC.
When all is said, this rhythm sounds complicated and the person labelling the rhythm sounds quite brilliant. The steps, though, are simple.
Various sites within the heart serve as pacemakers. While the sinus node is usually the dominant pacemaker, other pacemaker sites become active when faster pacemakers fail. Table 5.1 provides a range of expected rates of impulse formation for each of the pacemaker sites within the heart.
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. 103-105