How to take ECG

Electrocardiography

1. Electrocardiography is a recording from the body surface of the electrical changes that occurs within the heart during the cardiac cycle.
2. Instrument-Electrocardiograph.
3. Tracing-Electrocardiogram.
4. Einthoven-In 1901 was able to measure the Electrical activity of the Heart and this resolted in the birth of ECG.
5. ECG normal does not mean that patient is Normal.
6. ECG Abnormal does not mean that patient is Abnormal.
7. Always treat patient and not the ECG or Monitor.

Electrical conducting system of Heart

Electrical conducting system of Heart

1. Normal heart has a pacemaker in SA node situated at a junction of SVC and RA.
2. All the impolse arise in SA node, stimolus then passes to the AV node along the Internodal tracts, Wich are 3 bands of tissues.
3. AV Node has 3 zones Central lattice like zone has a low conduction velocity.
4. After AV Node there is Bundle of HIS. Form here the major path to the right ventricle is right bundle branch ( RBB ) and to the left ventricle is left bundle branch ( LBB ) There are left antenor division and left post division (LPD) of the left bundle branch (LBB)
5. In the ventricles the RBB & LBB terminate in the purkinje network which conveys the impolses to the ventricolar muscle and depolarize apex first and then the base.

HOW TO TAKE ECG

1.  Manual-Take Standardisation.
2.  I, II, III , aVR , aV1 , avF.
3.  Change the chest lead Position.
4.  At least 3 Complexes.
5.  Riytlim strips - long lead II
6.  Deep Inspiration - lead II
7.  Place the leads RL, LL, RA, LA
8.  V1-V6 [ Precordial leads ]

ECG Paper

1. Vertical Axis represents voltage.
2. Horizontal axis represents time.
3. 1mm - 1 small square - 0.04 sec.
4. Thick lines - 5 mm - big squares - 0.20 sec.
5. In one minute EGG paper moves by 300 big squares or 1500 small squares.
6. 0.2 sec= 1 big square.
7. In 60 sec. ECG paper moves by 300 big squares.
8. Ecg moves at a speed of 25mm/sec.

12 Lead ECG

1. There are 12 leads in ECG lead I,II,III,aVR,aVL,aVF,V1,V2,V3,V4,V5,V6.
2. 3 Bipolar limb leads which detect a Variation in frontal plane I , I I , III.
3. 3 Augmented unipolar limb leads aVR,aVL, aVF.
4. 6 unipolar chest or precordial leads V1-V6.

LEADS & SURFACE OF THE HEART

1.  II,III,aVF record changes on the Inferior or diaphragmatic surface of the Heart.
2.  I,aVL record from the lateral surface of the Heart.
3.  V1, V2-septum.
4.  V3, V4-anterior wall.
5.  V5, V6-lateral surface.
6.  I,aVL,V1-V6-extensive anterior surface of heart.
7.  I,aVL,V5-V6-lateral surface.
8.  I,aVL,V3-V6-Antero Lateral.
9.  V1-V4-anteroseptal.
10.  II,III,aVF,V5,V6-Infero Lateral.

CVS

INTERPRETATION

1.  Position
2.  Standardization
3.  Mechanism
4.  Voltage
5.  Electrical Axis
6.  Atrial rate
7.  Ventricolar Rate
8.  Rhythm
9.  ’P’Wave
10.  ’QRS’Complex
11.  ’T’Wave
12.  ’PR’Interval
13.  ’ST’Segment
14.  ’QT’duration
15.  ’Q’Wave
16.  Additional Findings
17.  ECG diagnosis
18.  Conclusion - Corelate Clinically.

STANDARIDISATION CALIBERATION

1.  Smallest division horizontally is 0.04 sec
2.  1MV Vertical deflection in resting Position shoold be 10 mm
3.  When the voltage is high we take half standardization.

VOLTAGE

1. Vertical axis represents voltage low voltage is said to be present when the largest QRS deflection in standard and unipolar limb leads is less than 5 mm ( not Precordial leads)

Causes ( Low )

1. Thick chest wall
2.  Emphysema
3.  Pericardial Effusion
4.  Hypothyroidism
5.  Myxoedema
6.  Hypothermia
7.  Incorrect standardization

Causes ( High )

1.  Thin chest wall
2.  Ventricolar hypertrophy
3.  Hyperthyroidism