EKG’s Kelly Marchant RN July 28, 2015 Adapted from NURO 438 Cardiac Dysrhythmias

Learning Objectives At 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 Anatomy 4 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 Generation Under 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 Displays electrical activity of heart 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 Basics Measures 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 Wave Final stage of repolarization, thought to be repolarization of Perkinje Fibers Not usually seen May indicate Hypokalemia Cardiomyopathy LVH Dig toxicity

Wave Matching Ventricular Depolarization Sets Normal Heart Rate Irregular Ventricular Beat A. AV Node Atrial Depolarization B. T wave 0.12-0.20 C. PAC Ventricular Repolarization D. SA Node Wide, bizarre QRS complex E. PVC F. P wave Early atrial beat G. QRS Complex Pacemaker site 0.06-0.12

EKG Paper At the 25 mm speed, Each mark at top is 3 seconds There are three large boxes between each mark Each large box is 1 second or 25 mm Each large box has 5 medium boxes in it Each medium box is 0.2 seconds or 5 mm Each 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 Rhythms Determine 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 & Rhythm Normal = 60-100 Tachycardia >100 Bradycardia <60 Regular Irregular Regularly-irregular

Sinus Arrhythmias SB = HR < 60 ST = HR >100

Steps to Interpreting Cardiac Rhythms Determine 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 Complex Represents 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 Interval Represents 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 QRS Represents 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 Points EKG 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/pati ent-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