its for Biomedical Engineering Aspirants

1. Electro Cardiography:
Systole – Contraction of Heart Muscle when Ventricle Muscle Pumps Blood into Pulmonary Artery & Aorta.
Diastole – Period of Dilation of Heart cavities while they fill with blood.
Arteries – Carries Oxygenated Blood from heart to all body parts.
Veins – Carries Deoxygenated Blood to Heart from all Body parts for purification.
Pulmonary Artery – Carries Deoxygenated Blood from right Chambers of Heart to Left Chambers of Heart
through Lungs for purification.
Pulmonary Veins – Carries Oxygenated Blood after purification through Lungs to Left Chambers of Heart.

2. PQRS Characteristics:
P – Depolarization
QRS – Combined result of Repolarization of Artery &
Depolarization of Ventricle.
T – Repolarization of Ventricle.
U – Result of after Potentials in Ventricle Muscle.
Values for Amplitude & Duration of ECG Parameters:
Amplitude: P Wave – 0.26mv
R Wave – 1.50mv
Q Wave – 25% of R Wave
T Wave – 0.1mv to 0.5mv
Duration: P-R interval – 0.10sec to 0.20sec
Q-T interval – 0.34sec 0.45sec
S-T interval – 0.05sec to 0.15sec
P Wave interval – 0.10sec
QRS interval – 0.08sec

3. ECG Amplifiers:
 2 Amplifiers are used to form Differential Amplifiers.
 One is inverting another is non-inverting amplifiers.
 Separately 2 inputs with 1 common output i.e., sum
of 2 output voltages.
 Inverting amplifier has 180⁰ out of phase w.r.t input.
 Measurement of bioelectric signals occur as a
potential difference b/n 2 electrodes is an i/p to
Differential amplifier.
 Bioelectric signals are b/n inverting and non-
inverting inputs of Amplifiers.

4. a)Electrodes
b)Leads:
Lead I: Left Arm(LA) & Right Arm(RA)
Lead II: Left Leg(LL) & Right Arm(RA)
Lead III: Left Leg(LL) & Left Arm(LA)
Right Leg(RL) is taken as Ground Reference

6.  Lead II Produces Greatest R Wave
Potential.
 When Amplitudes of 3 Limb Leads
are measured.
 R Wave Amplitude of Lead II is
equal to Sum of the R Wave
Amplitudes of Lead I & III.

8. Precordial Unipolar Leads:
V1 to V6 Leads.
V1-
V2-
V3-
V4-
V5-
V6-

9. Types of ECG Recorders:
1. Single Channel ECG Recorder
2. Three Channel ECG Recorder
3. Vector Electrocardiographs(Vector Cardiograph)
4. Electrocardiographs systems for Stress Testing
5. Continuous ECG Recording
6. ECG Clinical Applications
a) Vector Cardiograph(VCG)
b) Phonocardiograph(PCG)

10. Single Channel ECG Recorder:

12. Three Channel ECG Recorder:

14. ECG Systems for Stress Testing:
A Treadmill with automatic capability to change the speed and inclination in order to apply a specific physiological
stress.
An ECG radiometry system to allow recording of the ECBLG without artifacts while the patient is on treadmill.
An ECG monitor with a cathode ray display and heart rate meter.
An ECG Recorder.
An automatic or semiautomatic sphygmomanometer for the indirect measurement of blood pressure.
A defibrillator is usually kept available while test is being performed.
Stress Test system based on exercises consists of following points:

30. Blood Pressure Measurement:
1) Indirect Method
2) Automated Indirect Method
3) Direct Method