EKG’sKelly Marchant RNJuly 28, 2015Adapted from NURO 438Cardiac Dysrhythmias

Learning ObjectivesAt the completion of this presentation, the learner will be able to successfully…

Review Cardiac Anatomy & Physiology, including function, circulation & automaticity

Describe & Define waves on an EKG

Define & Identify Normal SR

Analyze EKG rhythm strips

Review

Cardiac Anatomy

Cardiac Anatomy4 Chambers, 2 Atria, 2 Ventricles

4 Valves

Acts as a PUMP

Receives deoxygenated blood from body, umps to lungs

Receives oxygenated blood from lungs, pumps to body

Cardiac Circulation

Automaticity

Impulse GenerationUnder Usual circumstances

Impulse generated from pacemaker cells in SA node

Impulse then travels to AV node

Impulse then travels to Bundle of His

Impulse then travels to Right and Left Bundle Branches

Impulse travels to Perkinje Cells that innervate ventricles

The EKG

EKG Graph

X Axis = time Y Axis = amplitude

Displays electrical activity of heart

Electrical impulse precedes contraction

Depolarization and repolarization are depicted as waves Atrial Depolarization = P wave Atrial repolarization occurs during ventricular

depolarization Ventricular depolarization = QRS complex Ventricular repolarization = T wave

Telemetry Placement

Red = Brake (right), Green = Gas (left)

Smoke (black) over Fire (red), Snow (white) on the Trees (green)

Stars and Stripes

EKG BasicsMeasures electrical potential between the

electrodes

AKA ‘Standard Limb Leads’

Leads I,II,III

Used to monitor only for dysrhythmias

Lead II most commonly used

Lead II

Cardiac Waves

The P Wave SA node is pacemaker,

Impulse begins in SA node moves R-> L, and down

Rate 60 – 100

Precedes atrial depolarization

PR interval 0.12-0.2 sec

Determines atrial rate

Irregular P wave Afib/flutter PAC SVT AV Block

The QRS Complex Represents normal

depolarization of the ventricles

Normal duration 0.06- 0.12 sec

Measured from Q wave (first deviation from isoelectric line) to S wave (the return to isoelectric line)

Abnormal QRS is abnormal depolarization PVC (wide bizarre QRS) BBB (prolonged QRS) Ventricular pre-excitation Cardiac pacemaker

The T wave

Represents Ventricular repolarization

Occurs during end of ventricular systole

Typically in same direction as QRS complex

Lasts 0.10 – 0.25 sec

Irregularities most often caused by pharmacology

The U WaveFinal stage of

repolarization, thought to be repolarization of Perkinje Fibers

Not usually seen

May indicate HypokalemiaCardiomyopathyLVHDig toxicity

Wave Matching1. Ventricular

Depolarization

2. Irregular Ventricular Beat

3. Atrial Depolarization

4. 0.12-0.20

5. Ventricular Repolarization

6. Wide, bizarre QRS complex

7. Early atrial beat

8. Pacemaker site

9. 0.06-0.12

10. Sets Normal Heart Rate

A. AV Node

B. T wave

C. PAC

D. SA Node

E. PVC

F. P wave

G. QRS Complex

EKG Paper

At the 25 mm speed, Each mark at top is 3 secondsThere are three large boxes between each markEach large box is 1 second or 25 mmEach large box has 5 medium boxes in itEach medium box is 0.2 seconds or 5 mmEach medium box is made up of 5 small boxes (or dots)Each small box (dot) = 0.04 seconds or 1 mm

EKG Paper

Steps to Interpreting Cardiac RhythmsDetermine the Heart Rate

Determine the Regularity

Identify and analyze P waves

Determine PR interval and AV conduction

Identify and analyze QRS complex

Determine site of origin of dysrhythmia

Identify dysrhythmia

Evaluate significance of dysrhythmia

Determine the Heart Rate The Six-second Method

Most common/least accurate Simplest, quickest

Heart Rate Calculator

The Rule of 300 Must be regular

R-R Interval Method Rhythm must be regular Distance between peaks of 2

R waves and /60

Describe the Rate & RhythmNormal = 60-100

Tachycardia >100

Bradycardia <60

Regular

Irregular

Regularly-irregular

Sinus ArrhythmiasSB = HR < 60

ST = HR >100

Steps to Interpreting Cardiac RhythmsDetermine the Heart Rate

Determine the Regularity

Identify and analyze P waves compare to QRS

Determine PR interval and AV conduction

Identify and analyze QRS complex

Determine site of origin of dysrhythmia

Identify dysrhythmia

Evaluate significance of dysrhythmia

Measuring the Waves

PR Interval Represents progression of electrical

impulse from the SA node or an ectopic pacemaker (in atria or AV junction) through entire conduction system of the heart to the ventricular myocardium

Normal duration 0.12 – 0.20

Irregular P waves demonstrate changes in atrial function (Afib/flutter, SVT, PAC)

PR >0.20 represents delayed conduction of impulse (AVB)

PAC’s Premature Atrial Contraction

P wave followed by normal QRS

Generally followed by noncompensatory pause

P waves vary, PR intervals normal

AV Ratio 1:1 Conduction

QRS ComplexRepresents normal

depolarization of the ventricles

Onset is point where first wave (Q) deviates from isoelectric line

End is where last wave (S) returns to isoelectric line

Duration 0.06 – 0.12

Irregular QRS complex correlate with changes in ventricular function (PVC, Vtach, Vfib)

QT IntervalRepresents time it takes for

ventricles to depolarize and repolarize

Prolonged QT associated with pericarditis, myocarditis, MI, LVH, hypothermia, CVA, increased IC trauma or hemorrhage, medication SE, electrolyte imbalances (K, Ca), or liquid protein diets

Irregular QRSRepresents

abnormal depolarization of ventricles

Irregular QRS present in Bundle Branch Block Ventricular

preexcitation Cardiac pacemaker

Single PVC

Apply the Eight Steps

Apply the Eight Steps

Apply the Eight Steps

Take Home PointsEKG is measurement of ELECTRICAL activity

Electrical activity precedes mechanical activity

Use the 8 Step Method

Identifying Normal Rhythms will enable you to identify Irregular Rhythms

Changes in atrial function displayed as irregular P wave (Afib/flutter, PAC, AVB)

Changes in ventricular function displayed as changes in QRS complex (PVC, BBB)

Living Arrythmias

https://www.youtube.com/watch?v=TJR2AfxVHsM

References

http://lifeinthefastlane.com/ecg-library/

http://ekg.academy/learn-ekg.aspx?seq=11&courseid=315

http://my.clevelandclinic.org/services/heart/patient-education

Questions???Please email me at Marchank@simmons.edu

with any questions

For a copy of the materials used in this presentation please visit

http://kellymarchant.weebly.com