Electrocardiogram

Vectorial Analysis of the Normal Electrocardiogram

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Electrocardiogram

Vectorcardiogram

Electrocardiogram

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.

Electrocardiogram

Vectorial Analysis of the Normal Electrocardiogram

Electrocardiogram

Mean Electrical Axis of the Ventricular QRS

Electrocardiogram

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

To the rightTo the left

Normal Ventricular Conditions That Cause Axis Deviation

Electrocardiogram

To the rightTo the left

Abnormal Ventricular Conditions That Cause Axis Deviation

Hypertrophic left ventricle Hypertrophic left ventricle

Also they cause a prolonged QRS complex

Electrocardiogram

To the rightTo the left

Abnormal Ventricular Conditions That Cause Axis Deviation

Left Bundle Branch Block

Right Bundle Branch Block

Also they cause a prolonged QRS complex

Electrocardiogram

Hypertrophy of the muscle

Old infarctionConditions

Surrounding the Heart:◦ Fluid in the

pericardium◦ Pleural effusion◦ Pulmonary

emphysema

Decreased Voltage

Increased Voltage

Conditions That Cause Abnormal Voltages of the QRS Complex

Arrhythmia

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

Arrhythmia

Arrhythmia Abnormal Sinus Rhythms

1. 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

2. Bradycardia (<60):◦In athletes (physiologic)oVagal Stimulation (carotid sinus

Syndrome)

Arrhythmia Abnormal Sinus Rhythms

Deep respiration

Quiet respiration

Sinus Arrhythmia

Block of Heart Signals Within the Intracardiac Conduction Pathways

Sinoatrial Block

ArrhythmiaBlock of Heart Signals Within the Intracardiac Conduction

PathwaysAtrioventricular Block

1 .First Degree Block

2 .Second Degree Block

3 .Third Degree Block

Stokes-Adams Syndrome-Ventricular Escape

ArrhythmiaPremature Ventricular Contractions (PVC)

•Prolonged QRS

• High voltage QRS

•T wave has opposite

direction than QRS

Natural Excitation of the Heart

Purkinje fibers and Reentry Mechanisms

Wolff-Parkinson-White syndrome.

Normal PR

WWS

Short PR

Arrhythmia

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