ECG 1

Leads 1,2,3,aVR,aVL,aVF 2

Limb leads & colours ? 3

Euro & Iran Rt Lt 4

5

6

Americ Rt Lt 7

Limb leads  "Christmas trees below the knees" (the green and red leads are placed on the lower extremities);  "white on right and green to go" (the white lead is placed on the right arm and the green lead is placed on the leg that controls the gas pedal, while the red lead is correspondingly placed on the leg that is closer to the brake); and  "smoke over fire" (the black left arm lead is placed over the red left leg lead, as with telemetric monitoring pads). 8

نامه سفید دست راست نامه سیاه دست چپ پای راست در بهشت پای چپ در جهنم 9

10

Precordial Leads= V1-V6 11

ECG Chest Leads 12

Precordial Leads  Measure potentials close to the heart, V 1 - V 6  Unipolar leads

ECG Chest Leads Precardial (chest) Lead Position  V1 = 4th ICS, right sternal border  V2 = 4th ICS, left sternal border  V3 = between V2 and V4  V4 = 5th ICS, left Mid clavicular Line  V5 = 5th ICS Left anterior axillary line  V6 = 5th ICS Left mid axillary line 14

Calibration, or standardization  refers to the amplitude of the waveforms on the tracing. It is usually set at a default value of 10 mm/mV Increasing the calibration to 20 mm/mV is helpful when trying to decipher P wave morphology.  Decreasing the calibration to 5 mm/mV is helpful in cases wherein the amplitude of the QRS complex (usually in the precordial leads) is so large 15

Paper speed  usually is set at a default of 25 mm/sec. It may be manipulated for purposes of deciphering a dysrhythmia,  It is important that the clinician examine all ECG tracings for standardization and speed parameters before attempting clinical interpretation. 16

ADDITIONAL lEADS  15 lead ECG  Posterior leads  Right leads  Invasive procedural leads 17

15 leads: V7-V8-V9 V7: post. Axillary line v8: tip of Lt scapula v9: near the border of paraspinal m. 18

Posterior leads  V8-V9 19

Right side leads; V4R (Rt 5th intercostal space mid-clavicular line) is the most useful lead for detecting STE in RV MI 20

Lewis leads RA &LL Vertical sternal (Barker) leads RA &LL Modified bipolar chest leads (MCL) MCL1: RA & LA MCL6: RA & LL 21 Alternative leads

WHY?  Rhythm assessment often requires ECGmonitoring over continuous periods of time,  making the standard 12-lead ECG (requiring 10 electrodes), and  even unipolar precordial V1 monitoring (requiring 5 electrodes), not feasible.  A number of alternative lead systems requiring fewer electrodes have been described. 22

&  vertical sternal leads produce a larger P wave than other systems 23

Einthoven’s triangle 24

Lewis: RA to LA >>> Lead2 25 RA LL

Barker: RA to LA >>> Lead2 26 LL RA

MCL1:RA to LA >>> Lead1 27 RA LA

MCL6:RA to LL >>> Lead2 28 LL RA

29 RA LL LA

 Lewis: lead 2  Barker: lead 2  MCL1: lead 1  MCL6: lead 2 30

Lead misplacement 34

Einthoven’s triangle 35

Normal ECG Signal  P – atrial depolarization  QRS complex – ventricular depolarization  T – ventricular repolarization

Reading 12-Lead ECGs The best way to read 12-lead ECGs is : 6-step approach: 1. Calculate RATE 2. Determine RHYTHM 3. Determine QRS AXIS 4. Calculate INTERVALS 5. Assess for HYPERTROPHY 6. Look for evidence of INFARCTION 37

Rate Determination 300/RR(large square) 38 Next QRS QRS

Rhythm  Sinus?  Each P followed by QRS, R-R constant 39

Rate Rhythm Axis Intervals Hypertrophy Infarct We can quickly determine whether the QRS axis is normal by looking at leads I and II. If the QRS complex is overall positive (R > Q+S) in leads I and II, the QRS axis is normal. QRS negative (R < Q+S) QRS equivocal (R = Q+S)

Rate Rhythm Axis Intervals Hypertrophy Infarct Now using what you just learned fill in the following table. For example, if the QRS is positive in lead I and negative in lead II what is the QRS axis? (normal, left, right or right superior axis deviation) 41 0o0o 30 o -30 o 60 o -60 o -90 o -120 o 90 o 120 o 150 o 180 o -150 o 0o0o 30 o -30 o 60 o -60 o -90 o -120 o 90 o 120 o 150 o 180 o -150 o QRS Complexes I Axis I II normal left axis deviation II

Rate Rhythm Axis Intervals Hypertrophy Infarct … if the QRS is negative in lead I and positive in lead II what is the QRS axis? (normal, left, right or right superior axis deviation) 42 0o0o 30 o -30 o 60 o -60 o -90 o -120 o 90 o 120 o 150 o 180 o -150 o 0o0o 30 o -30 o 60 o -60 o -90 o -120 o 90 o 120 o 150 o 180 o -150 o QRS Complexes I Axis I II normal left axis deviation right axis deviation II

0o0o 30 o -30 o 60 o -60 o -90 o -120 o 90 o 120 o 150 o 180 o -150 o Rate Rhythm Axis Intervals Hypertrophy Infarct … if the QRS is negative in lead I and negative in lead II what is the QRS axis? (normal, left, right or right superior axis deviation) 43 QRS Complexes I Axis I II normal left axis deviation right axis deviation right superior axis deviation 0o0o 30 o -30 o 60 o -60 o -90 o -120 o 90 o 120 o 150 o 180 o -150 o II

Rate Rhythm Axis Intervals Hypertrophy Infarct Is the QRS axis normal in this ECG? No, there is left axis deviation. The QRS is positive in I and negative in II.

Axis Determination 45 NORMAL RIGHT LEFT ALL UPRIGHT

Intervals 46

Hyperthrophy / Enlargement 48

Right Atrial Enlargement  Always examine Lead 2 for RAE  Tall Peaked P Waves, Arrow head P waves  Amplitude is 4 mm ( 0.4 mV) - abnormal  Pulmonary Hypertension, Mitral Stenosis  Tricuspid Stenosis, Regurgitation  Pulmonary Valvular Stenosis  Pulmonary Embolism  Atrial Septal Defect with L to R shunt 49

Right Atrial Enlargement 50 P wave voltage is 4 boxes or 4 mm

Left Atrial Enlargement  Always examine V 1 and Lead 1 for LAE  Biphasic P Waves, Prolonged P waves  P wave 0.16 sec, ↑ Downward component  Systemic Hypertension, MS and or MR  Aortic Stenosis and Regurgitation  Left ventricular hypertrophy with dysfunction  Atrial Septal Defect with R to L shunt 51

Left Atrial Enlargement 52 P wave duration is 4 boxes-0.04 x 4 = 0.16

Atrial Hypertrophy: Enlarged Atria RIGHT ATRIAL HYPERTROPHY Tall, peaked P wave in leads I and II LEFT ATRIAL HYPERTROPHY Wide, notched P wave in lead II Diphasic P wave in V 1

Ventricular Hypertrophy  Ventricular Muscle Hypertrophy  QRS voltages in V1 and V6, L1 and aVL  We may have to record to ½ standardization  T wave changes opposite to QRS direction  Associated Axis shifts  Associated Atrial hypertrophy 54

Normal Variations in ECG  May have slight left axis due to rotation of heart  May have high voltage QRS – simulating LVH  Mild slurring of QRS but duration < 0.09  J point depression, early repolarization  T inversions in V2, V3 and V4 – Juvenile T ↓  Similarly in women also T ↓  Low voltages in obese women and men  Non cardiac causes of ECG changes may occur 55

S.A.H. ECG changes 56

? 57

Pediatric ECG  This is the ECG of a 6 year old child  -Heart rate is 100 – Normal for the age  -See )V1 + V5( R >> 35 – Not LVH – Normal  -T ↓ in V1, V2, V3 – Normal in child  -Base line disturbances in V5, V6 due to movement by child 58

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