This document provides an introduction to biomedical engineering and electrocardiography (ECG). It outlines the instructor's contact information and teaching methods. It then discusses bio signals, electrodes used to detect bio signals, and the basic anatomy and functioning of the heart. Finally, it provides detailed explanations of ECG, including its definition, the different leads used to record the heart's electrical activity from multiple angles, and an overview of the typical components of an ECG signal (P wave, QRS complex, ST segment).

1. Lecture 1
Introduction to Biomedical Engineering

2. Basic Information
Instructor
 Kadry Ali Ezzat, Ph.D, Biomedical Engineering and Systems, Cairo University.
e-mail: kadry_ezat@hotmail.com
Mob.NO: 01064664762
Teaching and Learning Methods
Lectures
Tutorial sessions

3. Study Material
Course Notes
Power Point Presentations of lectures
Tutorials .

4. Bio signal “Biomedical Signal”

5. Bio Signal

6. Bio Signal

7. Bio Signal

8. Bio Electrodes

9. ELECTRODES

10. The center of the circulatory system is the heart, which is the main
pumping mechanism.
 The heart Is made of muscle.
The heart pumps oxygenated blood to the body and deoxygenated blood to
the lungs.
In the human heart there is one atrium and one ventricle for each
circulation, and with both a systemic and a pulmonary circulation there are
four chambers in total: left atrium, left ventricle, right atrium and right
ventricle.
Heart

11.  The right atrium is the upper chamber of the right side of the heart.
 The blood that is returned to the right atrium is deoxygenated (poor in
oxygen) and passed into the right ventricle to be pumped through the
pulmonary artery to the lungs for re-oxygenation and removal of carbon
dioxide.

12.  At rest the normal heart beats approximately
 60 - 80 times per minute, i.e. approximately 100,000 times a
day! Your heartbeat increases when you exercise. There are two
phases to your heart's pumping cycle:
 Systole: this is when your heart contracts, pushing blood out
of the chambers
 Diastole: the period between contractions when the muscle of
your heart (myocardium) relaxes and the chambers fill with
blood

14. ECG

15. ECG Definition
 Electrocardiography (ECG or EKG ) is a transthoracic (across the thorax or chest)
interpretation of the electrical activity of the heart over a period of time, as detected
by electrodes attached to the outer surface of the skin and recorded by a device
external to the body.

16.  Usually more than 2 electrodes are used and they can be combined into a number of
pairs (For example: Left arm (LA), right arm (RA) and left leg (LL) electrodes form
the three pairs LA+RA, LA+LL, and RA+LL).
 The output from each pair is known as a lead. Each lead is said to look at the heart
from a different angle. Different types of EKGs can be referred to by the number of
leads that are recorded

17.  A 12-lead ECG is one in which 12 different electrical signals are recorded at
approximately the same time and will often be used as a one-off recording of an
ECG, traditionally printed out as a paper copy
 A 12-lead ECG will show a short segment of the recording of each of the 12-leads.
 This is often arranged in a grid of 4 columns by three rows, the first columns being
the limb leads (I,II and III), the second column the augmented limb leads (aVR,
aVL and aVF) and the last two columns being the chest lead

18. Limb leads
Lead I: Iis the voltage between the (positive) left
arm (LA) electrode and right arm (RA) electrode:
Lead I = LA − RA.
Lead II: Is the voltage between the (positive) left leg
(LL) electrode and the right arm (RA) electrode the signal
shown in figure 2:
Lead II = LL − RA.
Lead III: Is the voltage between the (positive) left leg
(LL) electrode and the left arm (LA) electrode:
Lead III = LL − LA.

19. Limb leads
 In both the 5- and 12-lead configuration, leads I, II and III are called limb leads.
 The electrodes that form these signals are located on the limbs—one on each arm and one on the
left leg.
 The limb leads form the points of what is known as Einthoven's triangle.

22. Augmented limb leads:
Are Leads augmented vector right (aVR), augmented
vector left (aVL), and augmented vector foot (aVF)
• Avr= Exploring electrode located at the right
shoulder
• Avl= Exploring electrode located at the left
shoulder.
• Avf= Exploring electrode located at the left foot.

23. Augmented limb leads:

25. Chest or Precordial leads:
 The electrodes for the precordial leads
(V1, V2, V3, V4, V5 and V6) are placed directly on the
chest because of their close proximity to the heart, they
do not require augmentation.

27. ECG signal
• P-wave: ECG deflection representing atrial depolarization. Atrial
repolarization occurs during ventricular depolarization and is obscured.
• QRS complex: ECG deflection representing ventricular depolarization
• ST Segment: ECG defection representing ventricular repolarization.