electrocardiographs ecg n.
Skip this Video
Loading SlideShow in 5 Seconds..
Electrocardiographs ECG PowerPoint Presentation
Download Presentation
Electrocardiographs ECG

Loading in 2 Seconds...

play fullscreen
1 / 21

Electrocardiographs ECG - PowerPoint PPT Presentation

  • Uploaded on

Electrocardiographs ECG. OUTLINES :. Introducing what is meant by Biopotential signals. what is Electrocardiograph (ECG). The conduction system. The standard Lead system. The ECG machine Construction. . Introduction to Biopotential Signals. I. Electrocardiograph (ECG). I.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Electrocardiographs ECG' - katima

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
  • Introducing what is meant by Biopotential signals.
  • what is Electrocardiograph (ECG).
  • The conduction system.
  • The standard Lead system.
  • The ECG machine Construction.

The ECG is a graph showing the electrical activity due to the systole and diastole of the heart muscle

  • Which Records :

1-Amount of electrical activity of the heart.

2-The time required for the electrical activity to travel through the heart .

3-The rate and rhythm of the heart.


The heart acts as a blood pump.

  • Heart contracts generating action potential.
  • This potential creates electrical currents that spread from the heart throughout the body.
  • The spreading electrical currents create potentials differences which can be detected through surface electrodes
  • The waveform produced is called the electrocardiogram (ECG)
electrocardiogram ecg
Electrocardiogram (ECG)
  • Is a recording of electrical activity of heart conducted through ions in body to surface



ECG Graph Paper

  • Runs at a paper speed of 25 mm/sec
  • Each small block of ECG paper is 1 mm2
  • At a paper speed of 25 mm/s, one small block equals 0.04 s
  • Five small blocks make up 1 large block which translates into 0.20 s (200 msec)
  • Hence, there are 5 large blocks per second
  • Voltage: 1 mm = 0.1 mV between each individual block vertically

(SA node)

(AV node)


Normal conduction pathway:

SA node -> atrial muscle -> AV node -> bundle of His -> Left and Right Bundle Branches -> Ventricular muscle


Recording of the ECG:

  • Leads used:
  • Limb leads are I, II, II.
  • Each of the leads are bipolar; i.e., it requires two sensors on the skin to make a lead.
  • If one connects a line between two sensors, one has a vector.
  • There will be a positive end at one electrode and negative at the other.
  • The positioning for leads I, II, and
  • III were first given by Einthoven.
  • Form the basis of Einthoven’s triangle.
types of ecg recordings
Types of ECG Recordings
  • Bipolar leads record voltage between electrodes placed on wrists & legs (right leg is ground)
  • Lead I records between right arm & left arm
  • Lead II: right arm & left leg
  • Lead III: left arm & left leg




  • 3 distinct waves are produced during cardiac cycle
  • P wave caused by atrial depolarization
  • QRS complex caused by ventricular depolarization
  • T wave results from ventricular repolarization


ecg readout devices
ECG Readout devices

1- Medical Oscilloscope: vertical output is severely limited.

  • CRT persistence is very long .
  • ECG use a horizontal sweep speed 25 mm/s.

2- strip chart recorder (speed 25 mm/s) and has a grid pattern that is 50 mm wide.

The small grid are 1 mm apart.

The vertical scale is calibrated at 0.1 mV/mm