chap 8 reading ekgs

Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 8Advanced Cardiovascular

Monitoring Skills

Chapter 8Advanced Cardiovascular

Monitoring Skills


EKG Records:EKG Records:

• 1. amount of voltage generated by ht – vertical scale

• 2. time required for voltage to travel thru ht – horizontal scale


EKG Interpretation: 5 criteriaEKG Interpretation: 5 criteria

• 1. What is the rate?

– Quick estimate:

• Count # R waves in a 6 second strip x 10

• 6 second strip = 3 “tic” marks


• 2. Is rhythm regular or irregular?

– Measure distance between RR interval

– Measure throughout full 6 second strip


• 3. Are P waves present?

– Should be 1:1


Abnormal rhythms with P wavesAbnormal rhythms with P waves


4. What is the PR Interval? PRI4. What is the PR Interval? PRI

• Normal .12 - .20

• Beginning of P wave to beginning of QRS complex


5. What is the width of QRS complex?5. What is the width of QRS complex?

• Normal .12 or < (less)


Interpretation of Rhythm:Interpretation of Rhythm:

• What is the rhythm?

– Use information from 5 previous slides– 1. rate =

– 2. P waves =

– 3. PRI =

– 4. QRS =

– 5. Interpretation =


cheat sheet- Sinus Rhythmscheat sheet- Sinus RhythmsInterpretation Sinus Rhythm

(SR)Sinus Brady (SB)

Sinus Tach (ST)

Sinus (SA) Arrhythmia

Regularity

Rate

P waves

PRI

QRS


Sinus Rhythms: Impulse originates in SA node – normal pacemaker site

Sinus Rhythms: Impulse originates in SA node – normal pacemaker site

• Normal Sinus Rhythm - NSR:– Regularity – regular

– Rate - 60 – 100 / minute

– P waves = 1:1

– PRI = .12 - .20

– QRS = .12 or <


QuestionQuestion

What is a dysrhythmia?

A. Irregular rate only

B. Irregular rhythm only

C. Irregular rate and rhythm

D. Can be either or both irregular rate or rhythm


AnswerAnswer

D. Can be either or both irregular rate or rhythm

A dysrhythmia is an irregular heart rate, rhythm, or both. Remember that for the heart to be an effective pump, it must contract in two coordinated phases (atrial systole/ventricular diastole, followed by ventricular systole/atrial diastole). Rhythms that are irregular or rates that are too fast can affect the ventricles’ ability to fill with an adequate amount of blood or pump strongly enough to send the blood out of the heart.


Sinoatrial Node (Sinus) Dysrhythmias Sinoatrial Node (Sinus) Dysrhythmias

• Sinus bradycardia: the SA node fires electrical impulses at a rate that is slower than normal (< 60 impulses/ minute)

• Sinus tachycardia: the SA node fires electrical impulses at a rate that is faster than normal (>100 impulses/ minute)


Sinus Bradycardia - SBSinus Bradycardia - SB

• Regularity – regular

• Rate – less than 60 / min

• P waves – 1:1

• PRI - .12 - .20

• QRS - .12 or less


Sinus Tachycardia - STSinus Tachycardia - ST

• Regularity – regular

• Rate - > 100 / min

• P waves = 1:1

• PRI = .12 - .20

• QRS = .12 or <


Sinus Arrhythmia - SASinus Arrhythmia - SA

• Caused by a variety of factors: anxiety, stimulants, fever, exercise, medical conditions

• Regularity – irregular

• Rate – anything; freq. in normal rate of 60 – 100 / min

• P waves – 1:1

• PRI - .12 - .20

• QRS - .12 or <


Sinus Rhythms: Sinus Rhythms:Interpretation SR SB ST SA

Regularity Regular Regular Regular Irregular

Rate 60 – 100/ min < 60 min > 100 min Could be any rate, usually between 60 - 100

P waves 1:1 1:1 1:1 1:1

PRI .12 - .20 .12 - .20 .12 - .20 .12 - .20

QRS .12 or < .12 or < .12 or < .12 or <


Atrial Rhythms: Atrial Rhythms:Interpretation A-fib A-flutter AV Junction

Regularity

Rate

P waves

PRI

QRS


Atrial Dysrhythmias Atrial Dysrhythmias

• Atrial flutter: in atrial flutter, atrial contraction (represented by the P waves on the ECG) is regular but faster than normal (250 to 400 times per minute)

• Atrial fibrillation: caused by rapid, uncoordinated twitching of the myocardium of the atria; in atrial fibrillation, the P waves are irregular & small, & they occur at a rapid rate all along the ECG


Atrial Fibrillation : A FibAtrial Fibrillation : A Fib


Atrial Flutter : A FlutterAtrial Flutter : A Flutter


Question:Question:

The person with atrial fibrillation may feel which of the following?

A. Light-headed with palpitations

B. Unconscious

C. Nothing because there are no symptoms

D. Muscle movements may be uncoordinated


AnswerAnswer

A. Light-headed with palpitations

The ventricular rhythm is usually very irregular, and the rate of ventricular contraction is high (usually between 120 and 200 times per minute). When the ventricular rate is so rapid, the ventricles are not able to fill adequately with blood between beats. As a result, the maximum amount of blood is not sent out to the body with each beat. The person may feel light-headed and complain of chest palpitations (awareness that the heart is beating).


Atrioventricular Junction DysrhythmiasAtrioventricular Junction Dysrhythmias

• Junctional rhythm: occurs if the SA node fails to fire and send an electrical impulse through to the AV node or if the SA node fires the impulse too slowly


Junctional rhythms-begin in AV node & Bundle of HISSA node fails to fire or is too slow

Junctional rhythms-begin in AV node & Bundle of HISSA node fails to fire or is too slow

• Ventricular rhythm normal

• Rate is slower

• P waves absent or inverted

• May appear after QRS


P wave after QRS - junctionalP wave after QRS - junctional


Atrial Rhythms: Atrial Rhythms:Interpretation A-fib A-flutter AV Junction

Regularity Irregular-chaoticAtria quivers

RegularAtria flutters

Regular

Rate Ventricular: variesAtrial: chaotic, hard to read

Atrial: 250-400Ventricular: 75-100, may vary

40-60

P waves Irregular, small, rapid, hard to see

Flutter, sawtooth

None or inverted

PRI None Difficult to evaluate

Difficult to measure<.12

QRS <.12 <.12, hard to evaluate

Normal


Ventricular DysrhythmiasVentricular Dysrhythmias

• Premature ventricular contraction

• Ventricular tachycardia

• Ventricular fibrillation


Cheat Sheet-Ventricular DysrhythmiasCheat Sheet-Ventricular DysrhythmiasInterpretation PVC –

premature ventricular contraction

VT – Ventricular Tachycardia

VF – Ventricular Fibrillation

Asystole

Regularity

Rate

P waves

PRI

QRS


Premature Ventricular Contraction: PVCPremature Ventricular Contraction: PVC

• Ectopic beat – dangerous if occurs often

• Regularity – may interrupt the regularity of underlying rhythm

• Rate – depends on underlying rhythm

• P wave – will not be one before ectopic beat

• PRI – none in ectopic beat – measure underlying rhythm

• QRS – ectopic beat – wide and bizarre, also look at underlying rhythm


BigeminyBigeminy


couplets triplets


Ventricular Tachycardia - VTVentricular Tachycardia - VT

• Medical Emergency – most pts will be unconscious & can’t feel pulse

• Regularity – usually regular, can be slightly irregular

• Rate – 150 – 250 / min

• P waves – none

• PRI – none

• QRS - >.12


Ventricular Fibrillation - VFVentricular Fibrillation - VF

• Start CPR!!- check leads if pt. conscious, need defibrillated

• Regularity – baseline totally chaotic

• Rate – can’t determine

• P waves - ?

• PRI - ?

• QRS - ?


AsystoleAsystole

• No electrical activity

• Check leads if pt. conscious

• Start CPR


Cheat Sheet – Ventricular DysrhythmiasCheat Sheet – Ventricular Dysrhythmias

Interpretation PVC – premature ventricular contraction

VT – Ventricular Tachycardia

VF – Ventricular Fibrillation

Asystole

Regularity The underlying rhythm can be regular or irregular

Usually regular, can be irregular

Baseline totally chaotic

No electrical activity, only a flat line

Rate Determined by underlying rhythm

150 – 250Per min.

Can’t be determined

P waves Ectopic not preceded by a P wave

none No discernible P waves

PRI Ectopic comes from lower focus, no PRI

none none

QRS Wide and bizarre >.12

Wide and bizarre >.12

No discernible QRS complex


Cheat Sheet – BlocksCheat Sheet – Blocks

Interpretation

1st degree 2nd degree type 1

2nd degree type 2

3rd degree Bundle block

Regularity

Rate

P waves

PRI

QRS


Atrioventricular Blocks- AV node prevents electrical impulses from SA to go to ventricles

Atrioventricular Blocks- AV node prevents electrical impulses from SA to go to ventricles

• First-degree atrioventricular block

• Second-degree atrioventricular block

* Type I - Wenckebach rhythm

* Type II - Mobitz type I rhythm

• Third-degree atrioventricular block (Mobitz type II rhythm)


AV block 1st degreeAV block 1st degree

• All is normal except PR-I is abnormal


2nd degree, type I/ Wenckebach rhythm-

time b/t atrial depolarization and beginning ventricular depolarization becomes longer until blocked

PR-I longer with each impulse until there is a P wave without a QRS. Then is starts over


2nd degree –type II/Mobitz2nd degree –type II/Mobitz

• Time b/t atrial depolarization & ventricular depolarization is constant but not impulses are sent through AV node to ventricles.

• Normal constant PR-I until an impulse is blocked , then a P wave appears without a QRS


3rd degree/ Mobitz type II3rd degree/ Mobitz type II

• No electrical impulses are sent through the AV node. Atrial contraction occurs b/c SA node.

• Ventricular contraction occurs b/c perkinje fibers which causes slow rate

• A medical emergency!

• Need a pacemaker

• PR-I vary in length QRS wide & abnormal


Bundle branch blockBundle branch block

• Left or right branch unable to conduct the impulse to the perkinje fibers so only one side depolarizes

Wider than normal QRS, R wave may be small

• The QRS will be split & have a rabbit ear appearance.


Cheat Sheet – BlocksCheat Sheet – Blocks

Interpretation

1st degree 2nd degree type Wenckebach

2nd degree type 2

3rd degree Bundle block

Regularity Yes Regular until block occurs

Regular until block occurs

P & QRS are independent

Regular except at block

Rate Normal Atrial: WNLVentricular < 60

Atrial: WNLVentricular <60

Slow Varies according to block

P waves Present Present Present Present not related to QRS

Present

PRI >.12 Becomes longer with each complex

Normal &constant until block

None Varies

QRS Normal <.12 Eventually dropped <.12

Absent when blocked <.12

Wide & abnormalMedical emergency!

Split, wide & abnormal >.12Rabbit ears


Observations to Report to the Nurse ImmediatelyObservations to Report to the Nurse Immediately

• The PR interval is longer than earlier

• The QRS complex changed shape or widened

• The ECG shows a new dysrhythmia that was not there before

• C/O chest pain or discomfort

• C/O shortness of breath

• C/O dizziness

• Person unconscious


Artifacts Can Be Caused by:Artifacts Can Be Caused by:

• Electrical interference from other electrical equipment (such as an electric razor) or monitoring devices in the area

• Loose electrodes, especially if the person is diaphoretic (sweating) or recently repositioned

• Electrodes dried out

• Electrodes placed over an excessively hairy area

• Defective monitor or lead wires

• Patient movement (for example, from shivering or brushing the teeth)


Artifact:Artifact:


QuestionQuestion

What are abnormal ECG tracings that do not represent the heart’s electrical activity?

A. AV block

B. Dysrhythmia

C. Artifact

D. Bundle of His


AnswerAnswer

C. Artifact

Artifact can be caused by electrical interference from other electrical equipment (such as an electric razor) or loose electrodes, especially if the person is diaphoretic (sweating) or has recently been repositioned.


Question:Question:

In a 12-lead ECG, how many electrodes are placed on the body?

A. 12

B. 4

C. 10

D. 3


AnswerAnswer

C. 10

A 12-lead ECG is used to diagnose a heart condition. A 12-lead ECG uses 10 electrodes.


Scenario: Scenario:

• Mrs. Spencer is an elderly patient who has been admitted to your unit, 2A, after having abdominal surgery. She has been placed on telemetry to monitor her heart. Since her surgery, Mrs. Spencer has become a bit confused and has pulled off her telemetry leads three times already today. As you pass the station where the telemetry monitoring screens are, you notice that Mrs. Spencer’s rhythm is again looking irregular. You are really busy, and she has already pulled her leads off so many times today. What should you do?


Scenario: Scenario:

• Mrs. Jacobs is an elderly patient who has just been admitted to your unit with pneumonia. Her doctor has written an order for telemetry monitoring. What will some of your responsibilities be regarding Mrs. Jacobs’ telemetry?

chap 8 reading ekgs

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