Transcript Vectorial Analysis of the Normal Electrocardiogram

Session 6
Vectorial Analysis of
Electrocardiograms
Guyton 2011
Chapter 12, 13
1
Electrocardiogram
Objects
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What is the ECG?
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How the ECG was recorded?
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What are the characteristics of ECG paper?
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What are the waves, intervals and segments of ECG?
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What is lead?
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How many lead are usually recorded?
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What is the Einthoven law?
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What is vector?
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What can we earn from ECG?
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Vectorial Analysis of Electrocardiograms
Mean Electrical Axis of the Ventricular QRS
Normal Range
–30 to +110 degrees
Vectorial Analysis of Electrocardiograms
Vectorial Analysis of the Normal Electrocardiogram
Vectorial Analysis of Electrocardiograms
Vectorial Analysis of the Normal Electrocardiogram
0.01 s
0.035 s
0.02 s
0.05 s
0.06 s
Vectorial Analysis of Electrocardiograms
Vectorcardiogram
Vectorial Analysis of Electrocardiograms
Vectorial Analysis of the Normal Electrocardiogram
This sequence of repolarization is postulated to be caused by the high
blood pressure inside the ventricles during contraction, which greatly
reduces coronary blood flow to the endocardium, thereby slowing
repolarization in the endocardial areas.
Vectorial Analysis of Electrocardiograms
Vectorial Analysis of the Normal Electrocardiogram
Vectorial Analysis of Electrocardiograms
Mean Electrical Axis of the Ventricular QRS
Vectorial Analysis of Electrocardiograms
Normal Ventricular Conditions That Cause Axis Deviation
At the end of deep expiration
To the Left
When a person lies down
In stocky, fat people
At the end of deep inspiration
To the Right
When a person stands up
In tall, lanky people
Vectorial Analysis of Electrocardiograms
Abnormal Ventricular Conditions That Cause Axis Deviation
To the Left
Hypertrophic left ventricle
To the Right
Hypertrophic right ventricle
Also they cause a prolonged QRS complex
Vectorial Analysis of Electrocardiograms
Abnormal Ventricular Conditions That Cause Axis Deviation
To the Left
Left Bundle Branch Block
To the Right
Right Bundle Branch Block
Also they cause a prolonged QRS complex
Vectorial Analysis of Electrocardiograms
Conditions That Cause Abnormal Voltages of the QRS Complex
Increased Voltage
Hypertrophic left ventricle
Decreased Voltage
Hypertrophic right ventricle
Old infarction
Fluid in the pericardium
Pleural effusion
Pulmonary emphysema
Vectorial Analysis of Electrocardiograms
Old infarction
Normal tracing
Very early pattern
(hours after infarction)
Later pattern
(many hours to a few days)
Late established pattern
(many days to weeks)
Late established pattern
(many days to weeks)
Arrhythmia
Arrhythmia
Abnormal Sinus Rhythms
Tachycardia (> 100)
Increased body temperature
(up to 41 oC, 1 oC → 18 beat/min)
Stimulation of the heart by
the sympathetic nerves
(heart failure and shock)
Toxic conditions of the heart
Bradycardia (<60)
In athletes (physiologic)
Vagal Stimulation
(carotid sinus Syndrome)
Arrhythmia
Abnormal Sinus Rhythms
Sinus Arrhythmia
Quiet respiration
Deep respiration
Arrhythmia
Block of Heart Signals Within the Intracardiac Conduction Pathways
Atrioventricular Block
First Degree Block
Second Degree Block
Third Degree Block
Arrhythmia
Premature Ventricular Contractions (PVC)
• Prolonged QRS
•
High voltage QRS
• T wave has opposite
direction than QRS
The End
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