Page 1
Normal ECG: Rate and Rhythm
Read chapters 4 and 22
Page 2
ECG Interpretation*Standardization
Rate
1. RR interval
2. Heart rate
Rhythm
3. PP interval
4. P wave
width, height, shape, etc.
5. PR interval
6. QRS
width (and height)
axis
R wave progression
abnormal Q waves
ST segment
T waves
QT interval
U waves*See Chapter 22
Page 4
ECG Interpretation
Univ. of Wisconsin Medical School
• http://www.fammed.wisc.edu/pcc/ecg/
Page 5
The Normal ECG
Normal = normal sinus rhythm
Page 6
Rate
1.R-R interval
Is it regular?
2.What is the heart rate?
300, 150, 100, 75, 60, 50
300 / (# of large boxes)
1500 / (# of small boxes)
Count the number of cardiac cycles in 10 seconds and multiple by 6.
Page 8
Rate
Bradycardia
less than 60 bpm
Tachycardia
greater than 100 bpm
Page 9
Rate
3.P-P interval
Page 10
Rhythm
4.P wave
5.PR interval
6.QRS
Page 11
4. P Wave
Lead II and aVR
Positive in II
Negative in aVR
< 2.5 mm in amplitude
< 0.12 sec. in width
Page 12
Normal P Wave
aVR?
II?
Figures 4-2 and 4-3
Normal direction of atrial depolarization
Page 13
Abnormal P Wave
aVR?
II?
Direction of atrial depolarization with junction rhythm
This is an example of a retrograde conduction
Page 15
P wave
The same direction as QRS
Only one P wave in front of QRS
Do all the P waves look alike?
Page 16
5. PR interval
0.12 - 0.20 seconds
Page 17
6. QRS Complex
What is the width? (less than 0.10 seconds)
Do all the QRS waves in the same lead look alike?
R wave progressionAxisAbnormal Q waves (infarction)
Page 20
QRS Complex
Q waves
Page 21
Normal QRS
Two phases
brief phase; depolarization of ventricular septum
longer phase; depolarization of both ventricles but the left is larger
Page 22
First Phase
Depolarization of ventricular septum
Page 23
Second Phase
Depolarization of both ventricles but the left is larger
Page 24
Precordial Leads
V1
V6
Page 25
Normal QRS
V1? V1?
V6?V6?
Fig. 4-6
Page 27
Normal QRS
• Septal r wave
• Septal q wave
Page 28
6. QRS Complex
R wave progression
Page 29
Normal R Wave Progression
Transition Zone?
Page 30
R Wave Progression
Transition Zone?
Page 31
Transition Zone
Figure 4-7
Page 32
Early & Delayed Transition
• Figure 4-7
V1 V2 V3 V4 V5 V6
Page 33
6. QRS Complex
What is the electrical axis?
normal
left axis deviation
right axis deviation
extreme axis deviation
Page 34
7. St Segment
ST segment elevation or depression
(see chapters 8 & 9)
Page 35
8. T Wave
Normally positive where QRS wave is positive
V3- V6 and II, but negative in aVR
Abnormally tall T waves
Page 36
Practice
ECG Library
http://www.ecglibrary.com/ecghome.html
ECG: The Art of Interpretation
http://www.12leadecg.com/full/
Page 38
Not normal PR interval - Mobitz Type II block
Page 39
Not normalLAD, R wave progression
RBB w/inferior MI
Page 40
Not normal -First degree block, left atrial enlargement, left
bundle branch block, & inferior MI
Page 41
Not normalAtrial fibrillation
Page 43
Not normalJunctional rhythm
Page 44
Not normalLAD, late R wave progression
Acute MI
Page 45
Not normalPremature ventricular contractions
Page 46
Not normal
Ventricular tachycardia: note fast rate and wide bizarre QRS.
Page 48
Not normal
Second degree AV block - type II
Page 49
Not normalRAD, R wave progression
Page 50
Not normal
Third degree AV block
Page 51
Not normal
Right bundle branch block. Note the wide QRS waves
Page 53
Not normal
Left bundle branch block. Note the wide QRS waves
Page 54
a. yesb. verticalc. V3d. yese. yesf. yes
Page 55
2. No. Although there are P waves, they are negative. negative P waves indicate a retrograde conduction likely coming from the AV junction.