The document provides an overview of electrocardiography (ECG), including its definition, components such as waves, intervals, and segments, and the methodology for conducting an ECG using various leads. It covers the normal ECG tracing, how deflections are recorded, and introduces basic ECG interpretations related to heart conditions. Key topics include the historical context of ECG development and the Einstein's triangle concept explaining the relations between different leads.

1. ELECTROCARDIOGRAPHY
PHYSIOLOGY
TASK 2
ONLINE INTERNSHIP –WEEK 2 (30 DAYS)
INSTRUCTOR: MAM Dr. AQSA RABBANI
CANDIDATE: RIDA BATOOL
ECG

2. DEFINITION
• Electrocardiography is the technique of recording the
electrical activity of the heart. The recording itself is
called an electrocardiogram. The1st ECG machine
was designed by Einthoven, at the Dutch Medical
Meeting of 1893.

3. ECG PARTS
• A normal ECG is composed of a:
 Waves
 Intervals
 Segments

4. ECG WAVES
• A normal ECG waves composed of a:
 P wave
 QRS complex
 T wave
• The QRS complex is
often 3 separate waves
 Q wave
 R wave
 S wave

5. ECG SEGMENTS
• With segments, you talk about morphology:
elevation or depression or progression of
segments.
• PR segment
• ST segment

6. ECG INTERVALS
• An interval in an ECG is a duration of
time that includes one segment and
one or more waves.
• PR – interval During this interval, the cardiac impulses
travel from the SA node to the ventricles. Its duration is 0.12- 0.20
sec.
• QT-interval This occurs during ventricular depolarization
and ventricular repolarization. Its duration is 0. 40 - 0. 43 sec.
• ST- interval It occurs during ventricular repolarization
and its duration is 0. 32 sec.
• RR – interval This occurs between two R waves.

7. ELECTROCARDIOGRAM

8. ECG DEFLECTIONS
 The normal ECG tracing shows deflections or
waves and isoelectric segments.
 The waves (deflections) may be positive or
negative (above or below the zero line,
respectively).
 When depolarization moves towards positive
electrode, an upward deflection is produced.
 When it moves towards the negative electrode,
downward deflections recorded.
 The record shows depolarization followed by
repolarization of different regions of the heart.

9. ECG-How to do
• ECG leads: 12
• » V1 - Fourth intercostal space on the right
sternum
» V2 - Fourth intercostal space at the left
sternum
» V3 - Midway between placement of V2 and
V4
» V4 - Fifth intercostal space at the mid
clavicular line
» V5 - Anterior axillary line on the same
horizontal level as V4
» V6 - Mid-axillary line on the same
horizontal level as V4 and V5

10. ECG-How to do
• ECG leads: 12
• » RA (Right Arm) - Anywhere
between the right shoulder and right
elbow
» RL (Right Leg) - Anywhere below
the right torso and above the right
ankle
» LA(Left Arm) - Anywhere between
the left shoulder and the left elbow
» LL (Left Leg) - Anywhere below the
left torso and above the left ankle

11. ECG-How to do
• Frontal Leads
• By using 4 limb electrodes, you get 6 frontal leads that
provide information about the heart's vertical plane:
• Lead I
• Lead II
• Lead III
• Augmented Vector Right (aVR)
• Augmented Vector Left (aVL)
• Augmented vector foot (aVF)
• Leads I, II, and III require a negative and positive
electrode (bipolarity) for monitoring. On the other hand,
the augmented leads-aVR, aVL, and aVF-are unipolar
and requires only a positive electrode for monitoring.

12. ECG-How to do
• Transverse Leads
• By using 6 chest electrodes, you get
6 transverse leads that provide
information about the heart's
horizontal plane: V1, V2, V3, V4, V5,
and V6.
• Like the augmented leads, the
transverse leads are unipolar and
requires only a positive electrode.
The negative pole of all 6 leads is
found at the center of the heart.

13. ECG-How to do
• Einthoven's Triangle
• The Einthoven's triangle explains why there
are 6 frontal leads when there are just 4
limb electrodes.
• The principle behind Einthoven's triangle
describes how electrodes RA, LA and LL do
not only record the electrical activity of the
heart in relation to themselves through the
aVR, aVL and aVF leads. They also
correspond with each other to form leads I
(RA to LA), II (RA to LL) and III (LL to LA).

14. ECG interpretation
• Sinus tachycardia
• Sinus bradycardia
• Flutters
• Fibrillations
• Arrhythmias
• CVS diseases – MI
• Heart blocks etc

15. THANK YOU FOR
LISTENING