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1

CVS ECG II

Department of Physiology

Mahatma Gandhi Medical College & Hospitals, Jaipur

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2

Spread of cardiac impulse

Relation of A.P. and ECG Spread of depolarization

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3

Normal ECG

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4

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Lead axis

• Tri axial reference system

• Hex axial reference system

• Einthovan’s triangle /Einthovan’s law

• Electrical axis of limb leads

• Electrical axis of chest leads

• Concept of cardiac vectors

EINTHOVAN TRIANGLE• LEAD AXIS --Frontal plane

I 0

II + 60

aVF +90

III +120

aVL-30a VR -150

- 90

• Lead Axis-- Horizontal plane

Sternum

Vertebra

V1 V2

V3

V4

V5

V6

• Mean Vectors

ATRIAL Ventricular

Frontal plane vectors

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6

• Ventricular Vectors

Interventricular septum, Apex, right & left Ventr. Base, upper

part of septum, area around pulmonary conus

• Vector

Horizontal plane, Mean vector of ventricular depolarization

• Relationship of cardiac vectors to electrical axis of leads

• Basis of height of waves recorded

• Angle between lead axis and vector

• Cos θ

• Cos 90= zero, Cos zero= 1

12 LEAD ECG

To be continued

•Thank You!!