5. Electrocardiogram Action potentials
through myocardium
during cardiac cycle
produces electric
currents than can be
measured
Pattern
P wave
Atria depolarization
QRS complex
Ventricle depolarization
Atria repolarization
T wave:
Ventricle repolarization
11. The Six Step Approach
What is the Rate?
Is the Rhythm Regular?
Are there P-Waves?
Is the P-R Interval Normal?
Is the QRS Complex Normal?
Is There a P-Wave for Every QRS?
12. Normal Sinus Rhythm
Rate: 60 - 100
Regularity: Very
P-Waves: Present and Normal
P-R I: 0.12-0.20 sec
QRS: 0.04-0.12 sec and Normal
1 P: 1 QRS, no extras or shortages
13. Sinus Tachycardia
Rate: Over 100
Regularity: Regular
P-Waves: Present and Normal
P-R I: 0.12-0.20 sec
QRS: 0.04-0.12 sec and Normal
1 P: 1 QRS, no extras or shortages
14. Sinus Bradycardia
Rate: Less than 60
Regularity: Regular
P-Waves: Present and Normal
P-R I: 0.12-0.20 sec
QRS: 0.04-0.12 sec and Normal
1 P: 1 QRS, no extras or shortages
16. Atrial Flutter
Rate: Usually tachy
Regularity: Atria Regular
• Ventricles May be Irregular
P-Waves: Saw tooth Pattern 2:1, 3:1, 4:1...
P-R I: 0.12-0.20 sec on conducting beat
QRS: 0.04-0.12 sec
P-waves outnumber QRS
17. (Paroxysmal) Supra Ventricular Tach
Rate: 140-220
Regularity: Regular
P-Waves: Usually falls within the QRS-T complex (
sometimes not visible)
P-R I: Shorter than 0.12, or absent
QRS: 0.04-0.12 sec and Normal
P-QRS :Undeterminable
18. SVT
WPW
Usually based on Hx.
Delta wave on Q
Shortened PR-I
No Verapamil – Accessory Path use increase
19. 1st Degree Heart Block
Rate: 60 - 100
Regularity: Very
P-Waves: Present and Normal
P-R I: Longer than 0.20 sec
QRS: 0.04-0.12 sec and Normal
1 P: 1 QRS, no extras or shortages
20. 2nd Degree Heart Block (Type 1) Wenkebach
Rate: Can be Normal, or usually brady
Regularity: Irregular
P-Waves: Present and Normal
P-R I: Lengthens until beat is dropped
QRS: 0.04-0.12 sec and Normal
P-wave present on conducting beats, increased delay
causes missed QRS
21. 2nd Degree Heart Block (Type 2) Mobitz II
Rate: Less than 60
Regularity: Irregular
P-Waves: Present, 2:1, 3:1, 4:1
P-R I: 0.12-0.20 sec on conducting beat
QRS: 0.04-0.12 sec, may begin to widen
P-wave for every QRS and extras depending on conduction
ratio
22. 3rd Degree Heart Block (CHB)Complete Heart Block
Rate: Ventricular Rate 40-60
Regularity: Atria-Regular
• Vent-Regular
P-Waves: Present and Normal
P-R I: Atria independent of Ventricles
QRS: Usually greater than 0.12 sec
P-waves completely unrelated to QRS Complexes.
23. Junctional Rhythm
Rate: 40-60
Regularity: Regular
P-Waves: Inverted, Retrograde or Absent
P-R I: Shortened or absent
QRS: 0.04-0.12 sec
P-wave for every QRS, sometimes not visible
29. Premature Ventricular Contractions
Wide, Bizarre QRS Complex
Always identify the underlying rhythm first
Can appear in couplets, triplets, short runs of V-Tach,
bigeminy and trigeminy
Can be uni-focal or multi-focal
Caused by random firing within the ventricles
Not accompanied by a P-wave
30. PAC’s
P-QRS Complex appearing in an unexpected location
Caused by a stimulus from within the Atria, but not from
the SA Node
31. Bundle Branch Block
Any rhythm having a BBB will have a widened twin
peaked R-Wave
34. QT Prolongation
QT represents the ventricular refractory period
Normal
Men 450ms
Women 460ms
Corrected QT (QTc)
QTm/√(R-R)
Causes
Drugs (Na channel blockers)
Hypocalcemia, hypomagnesemia, hypokalemia
Hypothermia
AMI
Congenital
Increased ICP
35. Torsade de pointes
Torsades de pointes is a polymorphic ventricular
tachycardia . The phrase “torsades de pointes” means
“twisting on a point” which explains the action of the QRS
complex and how it varies from beat to beat. It is a
shockable rhythm.
36. Normal Variants
Always normal:
Sinus Arrhythmia
Supraventricular Extrasystoles
Partial RBBB
Often normal:
Sinus Bradycardia (and pauses in athletes)
First Degree Heart Block
Ventricular Extrasystoles
Left/Right Axis Deviation
RBBB
37. Special Situations
Dextrocardia – reverse precordial leads
Large breasts – don't place electrodes on top of breast
Bilateral breast implants you should apply V4, V5, and V6
close to the midaxillary line.
Note patient abnormalities on ECG
Do not place electrodes on open wounds, burns, or clear
dressings
Do not allow electrodes to touch one another
38. References
Pictures and info from:
Flip and See ECG, 2nd Edition
Cohn/Gilroy-Doohan
A great resource
Paramedic Paramedic Textbook, Revised 2nd Edition
Mick J. Sanders, Mosby
ECG’s Made Easy, 2nd Edition
Barbara Aehlert, RN, Mosby
Basic Dysrhythmias, Interpretation and Management,
3rd Edition
Robert J. Huszar, Mosby