Vectorial Analysis of Electrocardiograms Guyton 2011 Chapter 12, 13 Session 6 1

ElectrocardiogramElectrocardiogram What is the ECG? How the ECG was recorded? What are the characteristics of ECG paper? What are the waves, intervals and segments of ECG? What is lead? How many lead are usually recorded? What is the Einthoven law? What is vector? What can we earn from ECG? Objects 2

Mean Electrical Axis of the Ventricular QRS Normal Range –30 to +110 degrees Normal Range –30 to +110 degrees Vectorial Analysis of Electrocardiograms

Vectorial Analysis of the Normal Electrocardiogram Vectorial Analysis of Electrocardiograms

0.01 s 0.02 s s 0.05 s 0.06 s Vectorial Analysis of the Normal Electrocardiogram 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

At the end of deep expiration At the end of deep inspiration To the Right To the Left Normal Ventricular Conditions That Cause Axis Deviation Vectorial Analysis of Electrocardiograms When a person lies down In stocky, fat people When a person stands up In tall, lanky people

To the Right To the Left Abnormal Ventricular Conditions That Cause Axis Deviation Hypertrophic left ventricle Hypertrophic right ventricle Vectorial Analysis of Electrocardiograms Also they cause a prolonged QRS complex

To the Right To the Left Abnormal Ventricular Conditions That Cause Axis Deviation Left Bundle Branch Block Right Bundle Branch Block Vectorial Analysis of Electrocardiograms Also they cause a prolonged QRS complex

Decreased Voltage Increased Voltage Conditions That Cause Abnormal Voltages of the QRS Complex Hypertrophic left ventricle Hypertrophic right ventricle Vectorial Analysis of Electrocardiograms Old infarction Fluid in the pericardium Pleural effusion Pulmonary emphysema

Vectorial Analysis of Electrocardiograms 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) Old infarction

ArrhythmiaArrhythmia

ArrhythmiaArrhythmia Tachycardia (> 100) Increased body temperature (up to 41 o C, 1 o C → 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)

ArrhythmiaArrhythmia Deep respiration Quiet respiration Sinus Arrhythmia

ArrhythmiaArrhythmia Block of Heart Signals Within the Intracardiac Conduction Pathways Atrioventricular Block First Degree Block Second Degree Block Third Degree Block

ArrhythmiaArrhythmia Premature Ventricular Contractions (PVC) Prolonged QRS High voltage QRS T wave has opposite direction than QRS Prolonged QRS High voltage QRS T wave has opposite direction than QRS

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