1. Trayan Das
Biomedical Engineering
3rdYear
Univ. Roll No.-
12303111011
JIS COLLEGE OF ENGINEERING

2.  Introduction (what’s ECG)
 Different parts of an ECG graph
 ECG recording
 ECG leads
 Determining heart rate
 Uses of ECG
 Conclusion

4.  Early ECG machines  Modern ECG machines
ECG is invented by William Einthoven (1895).

5. Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers
Fig: Impulse conduction through heart

6.  P wave : Atrial
depolarization
 QRS complex :
Ventricular depolarization
 T wave : Ventricular
repolarization.
 atrial repolarization
merges with the
ventricular complex.
 U wave: repolarization
of papillary muscles.
 In most cases,U wave is
absent.

7. These are two isoelectric segments.

8. PR interval QT interval

9. Horizontally
1 small box 0.04 sec. or
(1x1) sqmm.
1 large box 0.2 sec. or (5x5)
sqmm.
Vertically
1 small box 0.1 mv
1 large box 0.5 mv

10.  Lead: difference in electrical potentials b/w two
points.
 There are two types of leads-
1)Bipolar leads: Two different points on the
body,
2)Unipolar leads: One point on the body & a
virtual reference point (with zero electrical
potential),located in the centre of heart.

11. Name of the leads No. of leads
Standard limb leads 3
Augmented limb leads 3
Chest leads 6

12. Fig. Standard limb leads
Lead I :VL-VR
LEAD II :VF-VR
LEAD III :VF-VL

13. Fig. Augmented limb leads
ECG representation

14. Fig. Chest leads

15.  Rule of 300/1500
 10 second rule

16.  Count the no. of “big boxes” between two QRS
complexes
 usually, distance between two successive tips of R
wave is taken.
 divide 300 by the resultant(1500 for smaller boxes).
 For regular rhythms.
 Heart rate is (300/6)=50 bpm

17.  ECGs record 10 secs. Of rhythm per page
 Count the no. of the beats present on the graph
 multiply it by 6.
 For irregular rhythms.
 Heart rate is (33x6)=198 bpm

18. With ECG,we can identify
 Arrhythmias
 Myocardial Ischemia & Infarction
 Pericarditis
 Chamber hypertrophy
 Electrolyte disturbances
(hyperkalemia,hypokalemia)
 Drug toxicity (digoxin & drugs)

19.  It’s a problem with the
rhythm of the
heartbeat.
 It has 2 types-
a)bradycardia:A
heartbeat that is too
slow,
b)tachycardia:A
heartbeat that is too
fast.
Tachycardia

20.  M. Ischemia: when
blood flow to heart
muscle is decreased by a
blockage of coronary
arteries.
 M. Infarction: when
blood stops flowing
properly to heart & heart
muscle is injured due to
not receiving enough
oxygen.
 Infarction is commonly
known as heart attack. Myocardial Infarction

21.  It’s an inflammation of pericardium (the
fibrous sac surrounding the heart).
 It often causes a chest pain.

22.  In this case, heart muscle
becomes thicker.
 It has 2 types-
Fig. Chamber hypertrophy
1)LeftVentricular
Hypertrophy
2)Right ventricular
hypertrophy

23.  Hyperkalemia: increase of
potassium (K+) in
blood(hyper=high, kalium
=potassium).
 Hypokalemia: when the
blood K+ amount is
decreased(hypo=low).
Hypokalemia

24.  An estimated 17 million people/year die of
CVDs, & the no. is gradually increasing.
 We can diagnose these diseases by ECG
monitoring.
 We need to take some precautions in ECG
monitoring, as it can cause some harm too (i.e.
exercise ECG).
 After all, for modern civilization, ECG is the best
option to diagnose the diseases & thus we can
further cure them.