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

ElectrocardiogramElectrocardiogram Vectorcardiogram

ElectrocardiogramElectrocardiogram 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.

ElectrocardiogramElectrocardiogram Vectorial Analysis of the Normal Electrocardiogram

ElectrocardiogramElectrocardiogram Mean Electrical Axis of the Ventricular QRS

ElectrocardiogramElectrocardiogram At the end of deep expiration When a person lies down In stocky, fat people At the end of deep expiration When a person lies down In stocky, fat people At the end of deep inspiration When a person stands up In tall, lanky people At the end of deep inspiration When a person stands up In tall, lanky people To the right To the left Normal Ventricular Conditions That Cause Axis Deviation

ElectrocardiogramElectrocardiogram To the right To the left Abnormal Ventricular Conditions That Cause Axis Deviation Hypertrophic left ventricle Also they cause a prolonged QRS complex

ElectrocardiogramElectrocardiogram To the right To the left Abnormal Ventricular Conditions That Cause Axis Deviation Left Bundle Branch Block Right Bundle Branch Block Also they cause a prolonged QRS complex

ElectrocardiogramElectrocardiogram Hypertrophy of the muscle Old infarction Conditions Surrounding the Heart: ◦ Fluid in the pericardium ◦ Pleural effusion ◦ Pulmonary emphysema Old infarction Conditions Surrounding the Heart: ◦ Fluid in the pericardium ◦ Pleural effusion ◦ Pulmonary emphysema Decreased Voltage Increased Voltage Conditions That Cause Abnormal Voltages of the QRS Complex

ArrhythmiaArrhythmia A) Normal tracing B) Very early pattern (hours after infarction) C) Later pattern (many hours to a few days) D) Late established pattern (many days to weeks) E) Very late pattern ( many months to years) after the infarction

ArrhythmiaArrhythmia

ArrhythmiaArrhythmia Abnormal Sinus Rhythms 1. 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 2. Bradycardia (<60): ◦ In athletes (physiologic) o Vagal Stimulation ( carotid sinus Syndrome) 1. 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 2. Bradycardia (<60): ◦ In athletes (physiologic) o Vagal Stimulation ( carotid sinus Syndrome)

ArrhythmiaArrhythmia Abnormal Sinus Rhythms Deep respiration Quiet respiration Sinus Arrhythmia Block of Heart Signals Within the Intracardiac Conduction Pathways Sinoatrial Block

ArrhythmiaArrhythmia Block of Heart Signals Within the Intracardiac Conduction Pathways Atrioventricular Block 1. First Degree Block 2. Second Degree Block 3. Third Degree Block Stokes-Adams Syndrome-Ventricular Escape

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

Purkinje fibers and Reentry Mechanisms Wolff-Parkinson-White syndrome. Normal PR WWS Short PR

ArrhythmiaArrhythmia Hypokalemia is a serious condition, but it is not as rapidly fatal as hyperkalemia Hypercalcemia leads heart to stops in systole (calcium rigor). Hypocalcemia leads causes prolongation of the ST segment and consequently of the QT interval