basic concept about ECG interpretation and its gives you idea for differentiation what is normal and abnormal ECG looks

1. PRESENTER: REKHA MARBATE

2.  Electric wiring of heart
 Normal ECG
 PR interval
 QRS complex
 Cardiac axis
 Axial Deviation
 How to report ECG
 Example

4. What is an EKG/ECG?
• The electrocardiogram (ECG) is a representation of the electrical
events of the cardiac cycle.
• Each event has a distinctive waveform
• the study of waveform can lead to greater insight into a patient’s
cardiac patho-physiology.

5. With ECGs we can identify
 Arrhythmias
 Myocardial ischemia and infarction
 Pericarditis
 Chamber hypertrophy
 Electrolyte disturbances (i.e. hyperkalemia, hypokalemia)
 Drug toxicity (i.e. digoxin and drugs which prolong the QT interval)

6. Depolarization
• Contraction of any muscle is associated with electrical changes
called depolarization
• These changes can be detected by electrodes attached to the surface
of the body

7. Pacemakers of the Heart
• SA Node - Dominant pacemaker with an intrinsic rate of 60 - 100
beats/minute.
• AV Node - Back-up pacemaker with an intrinsic rate of 40 - 60
beats/minute.
• Ventricular cells - Back-up pacemaker with an intrinsic rate of 20 -
45 bpm.

8. Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers

9. The “PQRST”
• P wave – Atrial depolarization
• T wave – Ventricular repolarization
• QRS – Ventricular depolarization

11. The ECG Paper
• Horizontally • Vertically
– One small box - 0.04 s – One large box - 0.5 cm
– One large box - 0.20 s 1mv signal moves stylus by 1cm

14.  If PR interval is short ,suggest excitation takes place through AV
conduction or spread/ conduction is abnormally fast from atrium to
ventricle

15. •Duration of QRS
complex suggest the
time taken for impulse
to excite through
ventricle.
• Normally= 0.12 or
less, if it is more QRS
complex get widen

16.  The standard EKG has 12 leads:
 3 Standard Limb Leads
 3 Augmented Limb Leads
 6 Precordial Leads

17. 3 Standard Limb Leads + 3 Augmented leads

19. Lat
sur
RT
atrium

20. Limited amount of information is also provided by height of P wave, QRS
complex and T wave ,if machine is properly calibrated.
Small complex- pericardial effusion and tall R wave indicate left
ventricular hypertrophy

22.  Average direction of spread of depolarization wave through the ventricle
as seen from front is called cardiac axis.

24.  Rt axial deviation:- rt ventricular hypertrophy, associated with pulmonary
condition put strain on rt side of heart and with congenital heart disease.
(pulmonary embolus)
 Lt axial deviation: lt ventricular hypertrophy, mostly problem is conduction
defect rather than increase in left ventriclar muscle bulk.

25.  Transition point:
point where R and S
are equal indicate
position of interventricular
septum
 If right ventricle enlarges to
Occupies more of pericardium
than normal , transition point
move from V3-V4 to V4-V5
or sometime V5-V6, this
clockwise rotation suggestive
Of chronic lung disease.

26.  Rhythm
 Conduction interval
 Cardiac axis
 Descripsion of QRS complex
 Description of ST segment and T wave