rhythm strips[1]

7/31/2019 Rhythm Strips[1]

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Webinar Wednesday June 13, 2012 11 AM EST

Presented by:

David W. Woodruff,

MSN, RN-BC, CNS, CMSRN, CEN

President, Ed4Nurses, Inc.

[email protected]

www.Ed4Nurses.com2012 Ed4Nurses, Inc. All rights reserved

5 Steps to Rhythm

Strip Interpretation

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5 Steps to Rhythm Strip Interpretation

2011 David W. Woodruff

www.ed4nurses.com

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Program description:

Upon completion of this program, the learner will be able to rapidly identify

common cardiac rhythms and be able to relate the appropriate treatment priorities forthose rhythms.

Objectives:

1. Describe the characteristics of a normal EKG complex.2. Identify the physiological characteristics of normal conduction.3. Use 5-steps to identify normal sinus rhythm.4. Compare and contrast EKG rhythms using a 5-step approach.5. Plan care for patients with abnormal EKG rhythms.

All material in 5 Steps to Rhythm Strip Analysis is copyrighted 2003-2011 by

Ed4Nurses, Inc. Duplicating, reproducing and distributing are prohibited without writtenconsent from Ed4Nurses, Inc.


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Normal conduction

Depolarization:Impulses begin at the Sinoatrial (SA) node, generating a P-wave. The impulse travels

through the electrical pathways to the Atrio-Ventricular (AV) node. The AV node delaysthe impulse, so that the atria and ventricles dont fire at the same time. The delay is seen

on the EKG as the P-R interval. As the impulse travels down the perkinge fibers in theventricles, it generates the QRS complex.

Repolarization:

In order for the heart to fire again, it needs to re-load. Electrical re-loading of the heart iscalled repolarization and is represented by the T-wave on the EKG.

Figure 1


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The EKG Complex:Keep in mind that the EKG complex represents electrical activity of the heart and

does not assure mechanical activity (contraction). Loss of contraction associated withcontinued electrical activity is called pulseless electrical activity (PEA).

How an EKG is obtainedAn EKG machine is a voltmeter. In other words, it reads electrical energy from

the body. The heart uses electrical energy to cause muscle cells to contract. By reading

the electrical energy of the heart, the nurse can tell if it is generated and conductedcorrectly.

An EKG is obtained by placing electrical sensors (leads) on the patients chest.Usually 12 leads are used to look at the heart from many angles. The EKG machine

doesnt look at all 12 leads at once; instead it chooses one at a time to view, and eachview we call a lead on the resulting tracing.

What do all the different leads mean?

The EKG machine looks at only one sensor (lead) at a time, but will use anotheras a ground. This gives the machine perspective for its view. To understand thisconcept, think of the process of taking a picture with a camera. Where you stand to take

the picture is equally as important as what direction you face when taking it. The EKGmachine takes pictures of the heart. By using different leads, the machine can change

its view or perspective on the heart. The EKGmachine looks from the positive (+) lead to

the negative (-) lead. In figure 2, the EKGmachine will be looking in the direction of the

arrow.

Why do we need all those differentleads?

Each lead looks from a different

perspective, and gives a different view of theheart. Using different leads allows the nurse to

watch electrical activity in many different partsof the heart.

What lead does my monitor at workuse?

To identify which lead your monitor is reading, look at the lead selection dial oron an EKG tracing. The lead will be identified by its abbreviation. For example, II

indicates lead II, V1 indicates the first chest lead.

The EKG and the patient

If a washing machine is not working, then an appliance repairman might be called

to attempt to repair it. He would hook up a voltmeter to determine if its got power.Even if its powered up, it may not work. The motor or a relay may be broken.

Figure 2


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An EKG is helpful in the same way. The EKG tracing indicates electrical activityof the heart. Usually normal EKG activity will correlate with normal mechanical activity

(cardiac output). However, it is possible that the patient can have normal EKG activityand be hemodynamically unstable.

Keep in mind that the EKG only represents the electrical activity of the heart and

does not measure mechanical activity. The blood pressure can be measured to assessmechanical activity (cardiac output). There is no direct correlation between the type ofEKG rhythm and the blood pressure. A heart rate of 50 may be perfectly normal for one

patient, and another would be in shock with the same heart rate. Blood pressuredetermines whether a rhythm is stable.

Validating EKGs

Sometimes a wire is cracked, or the lead is dried up and a poor connection ismade. In these situations the EKG machine may not be able to read accurately.

Whenever possible, the EKG should be validated by checking it in more than one lead.This is usually a simple procedure of turning the lead selector dial to another lead. Most

monitoring floors have policies about which lead is suppose to be monitored, soremember to turn the lead selector back to its original position.

Measuring intervals

The duration of the waveforms on the EKG should be short. To assess for

changes, the intervals can be measured. There are two measurements that we will usewith the 5-steps: the PR-interval, and the QRS duration. These are the most helpful in

analyzing rhythm strips.Intervals can be measured by comparing the distance on the tracing to the

markings on the EKG paper. The EKG paper is marked in time. Each small boxrepresents 0.04 seconds, and each large box represents 0.20 seconds. A large box

contains five small boxes, see figure 3.

Figure 3

There are 30 large boxes in each six-second strip. Fortunately, the tracing will bemarked with hash-marks at the top to designate each six-second increment. Using a six-

second strip is helpful in determining heart rate. Count the number of complexes in sixseconds and multiply it by ten for the heart rate per minute.


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The PR-interval is the distance between the beginning of the P-wave and thebeginning of the QRS complex. The purpose of measuring the PR-interval is to

determine if the impulse from the SA node is conducted to the ventricles through thenormal conduction pathways. Figure 4 shows where to measure the PR-interval.

Figure 4

The normal PR-interval is 0.12 to 0.20 seconds. Longer intervals indicateslowing of the impulse in the AV-node.

The QRS duration indicates how long it takes for the impulse to travel through theventricles. The QRS duration is measured at the beginning of the QRS complex until the

end of the complex (figure 5). A normal QRS duration is 0.04-0.08 seconds.

Figure 5

QRS duration determines whether we have a narrow complex or not. Widecomplexes are associated with aberrant conduction, or ventricular rhythms.


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Identifying normal rhythms

Sinus Rhythm

A heart rhythm that originates in the sinoatrial node and is normally conducted is

called a Normal Sinus Rhythm (NSR). The characteristics of a normal sinus rhythm are aregular rate between 60-100 beats per minute, a narrow complex, preceded by a P-wavewhere all the complexes look the same.

Normal conduction indicates that the myocardium is not irritable or injured. The realtest to determine whether a patient is hemodynamically stable is to check his blood

pressure. So, vital signs should be taken.Use the 5-Step approach to identify the rhythm:

Step 1. Rate: 60-100Step 2. RegularStep 3. P-wave precedes QRS (PR interval 0.16 sec)Step 4. Narrow complex (QRS duration 0.06 seconds)Step 5. All complexes look the same

All five questions were answered with a yes; therefore this is a normal sinus

rhythm. A normal sinus rhythm is usually associated with normal hemodynamics, but theblood pressure should be taken to validate stability. There is no treatment necessary ifthe patients blood pressure is normal.


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Sinus Tachycardia

A rhythm that originates in the SA node and is conducted normally, but thatexceeded 100 beats-per-minute is called Sinus Tachycardia (ST). Use the 5-Steps to

identify the rhythm below:

Step 1.Rate: >100Step 2.RegularStep 3.P-wave precedes QRS (PR interval 0.12)Step 4.Narrow complex (QRS duration 0.04 seconds)Step 5.All complexes look the same

Four of the five questions were answered affirmatively. The only negativeanswer was for the rate. This is a sinus rhythm (has a P-wave), it is just too fast. The rate

in the above strip is approximately 120. You will see the rate displayed on your monitor,or you can estimate it by counting the number of QRS complexes on a six-second strip.

The above strip is cut off prematurely, so the rate from the monitor will be used.Sinus tachycardia is caused by fever, anxiety, pain, dehydration, or hypoxemia.

Treatment would be for the underlying condition.


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Sinus Bradycardia

A rhythm that originates in the SA node (P-wave) but is less than 60 beats perminute is called Sinus Bradycardia (SB). To summarize the findings from the 5-step

analysis:

Step 1.Rate:


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Identifying abnormal rhythms

Atrial Flutter

The rhythm strip below has a regular ventricular rhythm, but has a saw-tooth wave

preceding the QRS instead of a P-wave. Note the difference in morphology between arounded P-wave and the sharp, saw-tooth flutter waves (F-waves). This pattern isconsistent with atrial flutter. Using the 5-step analysis, our findings would be:

Step 1.Rate: 60-150Step 2.RegularStep 3.Several F-waves precede QRSStep 4.Narrow complex (QRS duration 0.12)Step 5.All complexes look the same

In step 3 the flutter wave was discovered so that atrial flutter could be diagnosed.

In the strip above, the ventricular rate (QRS) is relatively slow at 60 beats per minute.There are three flutter (F-waves) for every QRS complex, a 1:3 ratio. If every flutter

wave were conducted, the ventricular rate would increase to 180 and the patient wouldprobably develop hypotension. Always check the blood pressure to assess the patients

stability.Treatment with digoxin, verapamil, or diltiazem would help to slow the

ventricular rate. Amiodarone, sotalol, or flecainide would be used to chemically convertthe rhythm back to sinus rhythm.


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Atrial Fibrillation

In the following rhythm, a P-wave is lacking again. However, no F-waves arepresent. Instead, there is a wavy or noisy baseline. This is consistent with fibrillation

waves (f-waves). Using our 5-steps atrial fibrillation (A-fib) can be identified.

a. Rate: 70 (can be abnormal with a-fib)b. Irregularc. Several f-waves precede QRSd. Narrow complex (QRS duration 0.08 seconds)e. All complexes look the same

The hallmark of atrial fibrillation is an irregularly-irregular rhythm. There is no

pattern to the irregularity. This happens because of an irregular pattern of atrial impulsesconducting to the ventricles.

Treatment for atrial fibrillation would be to control the rate from becoming toofast with digoxin, verapamil, diltiazem, or to convert it back to sinus rhythm with

cardioversion, or chemically with amiodarone, sotalol, flecainide. If the patient haspersistent atrial fibrillation he should be anticoagulated to prevent blood clots from

developing in the atria.


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Supraventricular Tachycardia

A very fast, but regular rhythm with a narrow complex is called supraventriculartachycardia (SVT). It is referred to as supraventricular because it is too fast to see P-

waves, and may be coming from somewhere other than the SA-node.

The 5-steps will identify this rhythm as a very fast, regular rhythm with a narrowcomplex.

Step 1.Rate: 140-300Step 2.RegularStep 3.P-wave may precede QRSStep 4.Narrow complex (QRS duration 0.04 seconds)Step 5.All complexes look the same

The rate in this strip is about 260. Rates exceeding 150 are often accompanied byhypotension, due to inadequate diastolic time for ventricular filling.

Therefore, treatment is necessary and includes vagal maneuvers, adenosine, beta-

blockers, verapamil, or cardioversion.


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Junctional Rhythm

A rhythm originating in the AV-node is called a junctional rhythm. The characteristicsigns are a slow rhythm without a P-wave. The 5-steps would identify the following

characteristics:

Step 1.Rate: 40-60 (accelerated 60-100)Step 2.RegularStep 3.P-wave absent or invertedStep 4.Narrow complex (QRS duration 0.06 seconds)Step 5.All complexes look the same

In a junctional rhythm the P-wave may be inverted and very close to the QRS because

it is being generated by the AV node, or it may be absent entirely. The rate in this strip is50; the blood pressure should be assessed to determine stability. Symptomatic junctional

rhythms are treated with atropine or a pacemaker.


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First-degree AV-Block

The AV node can function as a pacemaker in junctional rhythms as well as act todelay the impulse from the SA-node, so that the atria and ventricles dont contract at the

same time. Sometimes the AV-node may delay the impulse too long and this is called a

first-degree AV-block. Our 5-step analysis will identify the following characteristics:Step 1.Rate: 60-100Step 2.RegularStep 3.P-wave precedes QRS: long PR-interval (0.38 seconds)Step 4.Narrow complex (QRS duration 0.06 seconds)Step 5.All complexes look the same

As long as the blood pressure is normal, treatment is not necessary. It is important to

observe the patient for development of a greater degree of AV blockage. A first-degreeblock can progress to a second-degree or third-degree block.


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Second-degree AV-Block

A greater degree of AV blockage is called a second-degree block. The cardinal signsare that the rhythm is irregular and that more than one P-wave precedes the QRS. Notice

in the strip below that there is a long space between the second and third complexes, with

one P-wave immediately after the T-wave and another preceding the third QRS complex.Using the 5-stap method, the following characteristics are identified:

Step 1.Rate: variesStep 2.IrregularStep 3.P-wave precedes QRS (PR interval varies)Step 4.Narrow complex, but some dropped (QRS duration 0.08 seconds)Step 5.All complexes look the same

Again, the blood pressure should be assessed to determine if the patient is stable.Digoxin can cause this rhythm and should be discontinued. A pacemaker may be

necessary if the rate is slow and the blood pressure drops.


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Mobitz Type I Block

Another type of second-degree block is called Mobitz Type I, or Wenckebach. In thistype of block the PR-interval becomes progressively longer, until a QRS complex is

dropped. In the strip below, notice how the PR-interval is long in the first complex (0.32

seconds) and longer yet in the second (0.42 seconds). A P-wave is in the T-wave of thesecond complex and a third complex is not conducted causing the delay between complextwo and complex three. The characteristics of a Mobitz Type I second-degree block can

be found in the 5-step analysis:Step 1.Rate: variesStep 2.IrregularStep 3.P-wave precedes QRS: PR-interval becomes progressively longer, until a

QRS is dropped.Step 4.Narrow complex (QRS duration 0.10 seconds)Step 5.All complexes look the same

Digoxin can slow conduction through the AV-node and cause this type of block.Therefore digoxin should be held. Atropine or a pacemaker will be necessary if the

patient is symptomatic, so check the blood pressure.


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Third-degree AV-Block

Loss of all communication between the atria and ventricles is called a third-degreeAV-block. P-waves will be regular and flow through the strip, but they are not conducted

to the ventricles and there is no relationship between the P-wave and the QRS complex.

The QRS complex is originating in the ventricle and typically has a very slow rate. The5-step analysis would identify the following characteristics:

Step 1.Rate:


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Ventricular Tachycardia

A rapid rate that comes from the ventricles is called ventricular tachycardia (V-tach). The rhythm will be fast (>100 beats per minute), regular, and have a wide QRS

complex. The 5-step analysis would identify:

Step 1.Rate: 100-220Step 2.RegularStep 3.No P-wavesStep 4.Wide complex (QRS duration 0.12 seconds)Step 5.All complexes look the same

Treatment depends on whether there is a pulse. If the patient has a pulse and a

stable blood pressure the rhythm will be converted using medications. Lidocaine,amiodarone, procainamide, and sotalol are used to convert v-tach. If the patient has a

pulse, but the blood pressure is unstable then cardioversion is performed and followed bylidocaine, or procainamide.

If the patient does not have a pulse, call a code! Treatment includes immediatedefibrillation, cardiopulmonary resuscitation, and administration of epinephrine.


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Ventricular Fibrillation

Loss of all coordinated activity of the heart results in ventricular fibrillation (V-fib).The rhythm strip will show a saw-tooth, or wavy pattern to the baseline without QRS

complexes. Characteristics from the 5-step analysis include:

Step 1.Rate: none detectableStep 2.IrregularStep 3.No P-wave or QRSStep 4.Wide, bizarre, chaotic complexesStep 5.Complexes look different

There is no coordinated activity of the heart during V-fib, and the patient will have no

pulse or blood pressure. Immediate treatment with cardiopulmonary resuscitation anddefibrillation is associated with improved outcomes. If defibrillation does not convert the

patient back to a stable rhythm, then epinephrine should be administered. Lidocaine,amiodarone, procainamide, or magnesium may be a helpful pharmacologic agent to

convert V-fib.


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Asystole

No electrical activity of the heart is called asystole. The EKG strip will show a flat-line, as illustrated in the strip below. A flat-line EKG strip can also be obtained if the

lead wires are not properly connected, therefore asystole should be confirmed in two

leads. Turn the dial on your monitor to a different lead to confirm asystole. Thecharacteristics of asystole are:

Step 1.Rate: noneStep 2.Flat lineStep 3.P-waves may be presentStep 4.QRS complexes absentStep 5.No electrical or mechanical activity

Loss of electrical activity corresponds to loss of mechanical activity. This patientwill have neither pulse nor blood pressure. Cardiopulmonary resuscitation should be

started at once, followed by epinephrine and atropine. A pacemaker may also be helpfulin stimulating contraction.


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Pulseless Electrical Activity

When there is electrical activity of the heart, but no mechanical activity, there will beno pulse or blood pressure. This phenomenon is called pulseless electrical activity

(PEA). Any type of EKG rhythm could be present. However, it is often a ventricular

rhythm. In PEA there is electrical activity of the heart but no mechanical activity. TheEKG will look OK, but there is no pulse. PEA can be caused by compression of the heartby fluid. This happens in cardiac tamponade, tension pneumothorax, and chest trauma.

The characteristics from our 5-step analysis will show:Step 1. Rate: variesStep 2. May be regular or irregularStep 3. P-waves may be presentStep 4. QRS complex presentStep 5. No detectable pulse or B/P with electrical activity

Treatment is necessary because there is no mechanical activity and therefore no

pulse or blood pressure. Immediate cardiopulmonary resuscitation, followed byadministration of epinephrine and atropine is the treatment of choice. It is also important

to correct the mechanical cause. If the patient has cardiac tamponade, CPR andmedications will not deliver a stable blood pressure until the tamponade is corrected.

Summary

The 5-steps to Rhythm Strip Interpretation is a simple and accurate system to help

you rapidly identify abnormal rhythm strips. Practice using the system on every strip youcan. That way the abnormal findings will really stand out when you see them.

Treatment of any abnormal rhythm depends on whether the patient issymptomatic. Monitor his blood pressure to find out. Even with an abnormal rhythm he

may still maintain his perfusion and no treatment will be immediately necessary. Be sureto notify the physician of any changes in cardiac rhythm, though.


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Post-test

1. EKG rhythms with a rate of greater than 100 or less than 60 may be associatedwith:

a. Hypertensionb. Hyperkalemiac. Hypotensiond. Hypokalemia

2. A wide QRS complex indicates:a. Normal conductionb. Rapid conductionc. Slowed conductiond. No conduction

3. Why is it important that all the QRS complexes look the same?a. Indicates conduction through normal pathwaysb. Indicates conduction through pacemakersc. Indicates that the monitor is workingd. Indicates abnormal conduction

4. A normal PR-interval is:a. 0.02 secondsb. 0.18 secondsc. 0.22 secondsd. 6 seconds

5. In sinus tachycardia which of the following variables is abnormal?a. Rhythmb. Shape of complexc. PR intervald. Rate

6. A first-degree heart block may result in:a. Long QRS durationb. Fast ratec. Missed beatsd. Long PR interval

7. The primary characteristic of supraventricular tachycardia (SVT) that makes itunstable is:

a. Rhythmb. Ratec. Shape of complexd. PR interval


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8. Initial emergent treatment for ventricular fibrillation is:a. Defibrillationb. Epinephrinec. CPRd. Lidocaine

9. A flat-line on the monitor may be asystole. What common complication canimitate asystole on the monitor?

a. Unplugged monitorb. Wrong lead selectedc. Disconnected leadd. Dead battery in monitor

10.The condition that will result in a EKG rhythm on the monitor, but no pulse orblood pressure is called:

a. Asystoleb.

Third-degree blockc. Ventricular fibrillation (VF)

d. Pulseless electrical activity (PEA)11.The PR-interval is measured:

a. From the beginning of the QRS to the end of the T-waveb. From the beginning to the end of the P-wavec. From the beginning of the P-wave to the beginning of the QRSd. From the end of the P-wave to the beginning of the QRS

12.The AV node has the following functions:a. Can act as the primary pacemakerb. Slows the impulse before the ventriclesc. Generates an impulse from 60-100 beats per minuted. Innervates the ventricles

13.A junctional rhythm originates where?a. The AV nodeb. The ventriclesc. The SA noded. In the atria

14.The hallmark of atrial fibrillation is:a. Regular rhythmb. Fast pulsec. Irregular rhythmd. Slow pulse


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15.Atrial flutter is identified by its:a. P-wavesb. QRS complexc. f-wavesd.

F-waves

Answers:

1. c2. c

3. a4. b

5. d6. d

7. b8. c

9. c.10. d

11. c12. b

13. a14. c

15. d


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Additional Resources

Book:

McPhee, A. T. (1997). ECG interpretation made incredibly easy. Springhouse:

Springhouse.

On-line:

The EKG Site: http://www.the-ekg-site.com. Accessed August 3, 2011

EKG presentation:http://physioweb.med.uvm.edu/cardiacep/CardiacEP2003_files/frame.htm. Accessed

August 3, 2011.

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