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Electrocardiogram (ECG)

Guyton

2011

Chapter 11

Session 5

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Electrocardiogram

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

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Electrocardiogram

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Electrocardiogram

Atrial contraction

BeginsComplet

e

Ventricular contraction

BeginsComplet

e

Ventricular Relaxation

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Electrocardiogram

Recording of the ECG

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Recording of the ECG

Electrocardiogram

Depolarization

Begins

Complete

Repolarization

Begins

Complete

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Flow of Current Around the Heart During the Cardiac Cycle

Electrocardiogram

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Flow of Electrical Currents in the Chest Around the Heart

Electrocardiogram

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Electrocardiogram

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Electrocardiogram

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Time (s) Voltage (mv) Wave or complex and

interval

0.1 - 0.3 P

1 - 1.5 QRS

0.2-0.3 T

0.16 PQ (PR)

0.35 QT

Electrocardiogram

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Heart Rate Determination from ECG

squares small ofnumber the

1500 RateHeart

squares large ofnumber the

300 RateHeart

60 inteval RR

1 RateHeart

Electrocardiogram

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Electrocardiographic Leads

Electrocardiogram

Bipolar Limb Leads

Unipolar Limb Leads

Chest Leads (PrecordiaI Leads)

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

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Electrocardiographic Leads

aVF

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Electrocardiographic Leads

Standard Bipolar

Limb Leads

Electrocardiogram

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Standard Bipolar Limb Leads

Electrocardiogram

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Einthoven's LawI + III = II

Electrocardiogram

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Electrocardiogram

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Vectorial Analysis of Electrocardiograms

Electrocardiogram

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Unipolar Limb Leads

Electrocardiogram

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Vectorial Analysis of Electrocardiograms

Electrocardiogram

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Electrocardiographic Leads (Horizontal plane)

Electrocardiogram

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The anatomical orientation of the heart

The relative sizes of its chambers

The various disturbances of rhythm

Conduction, the extent and location of ischemic

damage to the myocardium and its progress

The effects of altered electrolyte concentrations

The influence of certain drugs (notably digitalis,

antiarrhythmic agents, and Ca++channel antagonists).

Electrocardiogram

Findings from ECG

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The End