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

2. 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

3. Review

4. Cardiac Anatomy

5. 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

6. Cardiac Circulation

7. Automaticity

8. 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

9. The EKG

10. 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

11. Telemetry Placement Red = Brake (right), Green = Gas (left)
Smoke (black) over Fire (red), Snow (white) on the Trees (green)
Stars and Stripes

12. 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

13. Lead II

14. Cardiac Waves

15. 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 sec
Determines atrial rate
Irregular P wave
Afib/flutter
PAC
SVT
AV Block

16. The QRS Complex Represents normal depolarization of the ventricles
Normal duration 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

17. 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

18. The U Wave
Final stage of repolarization, thought to be repolarization of Perkinje Fibers
Not usually seen
May indicate
Hypokalemia
Cardiomyopathy
LVH
Dig toxicity

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

20. 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

21. EKG Paper

22. 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

23. 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

24. Describe the Rate & Rhythm
Normal =
Tachycardia >100
Bradycardia <60
Regular
Irregular
Regularly-irregular

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

26. 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

27. Measuring the Waves

28. 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)

29. 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

30. 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)

31. 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

32. Irregular QRS Represents abnormal depolarization of ventricles
Irregular QRS present in
Bundle Branch Block
Ventricular preexcitation
Cardiac pacemaker

33. Single PVC

34. Apply the Eight Steps

35. Apply the Eight Steps

36. Apply the Eight Steps

37. 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)

38. Living Arrythmias
/watch?v=TJR2AfxVHsM

39. References http://lifeinthefastlane.com/ecg-library/
ekg.aspx?seq=11&courseid=315
ent-education

40. Questions???
Please me at with any questions
For a copy of the materials used in this presentation please visit