Electrocardiogram (ECG) Guyton 2011 Chapter 11 Session 5 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

ElectrocardiogramElectrocardiogram 3

ElectrocardiogramElectrocardiogram Atrial contraction BeginsComplete Ventricular contraction BeginsComplete Ventricular Relaxation 4

ElectrocardiogramElectrocardiogram Recording of the ECG 5

ElectrocardiogramElectrocardiogram Depolarization Begins Complete Repolarization Begins Complete 6

Flow of Current Around the Heart During the Cardiac Cycle ElectrocardiogramElectrocardiogram 7

Flow of Electrical Currents in the Chest Around the Heart ElectrocardiogramElectrocardiogram 8

ElectrocardiogramElectrocardiogram 9

ElectrocardiogramElectrocardiogram 10

Time (s)Voltage (mv) Wave or complex and interval P QRS T 0.16PQ (PR) 0.35QT ElectrocardiogramElectrocardiogram 11

Heart Rate Determination from ECG ElectrocardiogramElectrocardiogram 12

Electrocardiographic Leads ElectrocardiogramElectrocardiogram Bipolar Limb Leads Unipolar Limb Leads Chest Leads (PrecordiaI Leads) I II III aVR aVL aVF V1 V2 V3 V4 V5 V6 13

Electrocardiographic Leads aVF 14

Electrocardiographic Leads Standard Bipolar Limb Leads ElectrocardiogramElectrocardiogram 15

Standard Bipolar Limb Leads ElectrocardiogramElectrocardiogram 16

Einthoven's Law I + III = II Einthoven's Law I + III = II ElectrocardiogramElectrocardiogram 17

ElectrocardiogramElectrocardiogram 18

Vectorial Analysis of Electrocardiograms ElectrocardiogramElectrocardiogram 19

Unipolar Limb Leads ElectrocardiogramElectrocardiogram 20

Vectorial Analysis of Electrocardiograms ElectrocardiogramElectrocardiogram 21

Electrocardiographic Leads (Horizontal plane) ElectrocardiogramElectrocardiogram 22

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). 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). ElectrocardiogramElectrocardiogram Findings from ECG 23

The End 24