Session 5 Electrocardiogram ECG Guyton 2011 Chapter 11

Session 5 Electrocardiogram (ECG) Guyton 2011 Chapter 11 1

Electrocardiogram Objects � 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? 2

Electrocardiogram 3

Electrocardiogram Atrial contraction Begins Complete Ventricular contraction Begins Ventricular Relaxation Complete 4

Electrocardiogram Recording of the ECG 5

Electrocardiogram Recording of the ECG Begins Depolarization Complete Begins Repolarization Complete 6

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

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

Electrocardiogram 9

Electrocardiogram 10

Electrocardiogram Wave or complex and interval Voltage (mv) P 0. 1 - 0. 3 QRS 1 - 1. 5 T 0. 2 -0. 3 Time (s) PQ (PR) 0. 16 QT 0. 35 11

Electrocardiogram Heart Rate Determination from ECG 12

Electrocardiogram Electrocardiographic Leads Bipolar Limb Leads I II III a. VR Unipolar Limb Leads a. VL a. VF Chest Leads (Precordia. I Leads) V 1 V 4 V 2 V 5 V 3 V 6 13

Electrocardiographic Leads a. VF 14

Electrocardiogram Electrocardiographic Leads Standard Bipolar Limb Leads 15

Electrocardiogram Standard Bipolar Limb Leads 16

Electrocardiogram Einthoven's Law I + III = II 17

Electrocardiogram 18

Electrocardiogram Vectorial Analysis of Electrocardiograms 19

Electrocardiogram Unipolar Limb Leads 20

Electrocardiogram Vectorial Analysis of Electrocardiograms 21

Electrocardiogram Electrocardiographic Leads (Horizontal plane) 22

Electrocardiogram Findings from ECG � 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). 23

The End 24