ULF - Electrocardiography For Students

Electrocardiography : 

Electrocardiography Dr. S. Aswini Kumar. MD Professor of Medicine Medical College Hospital Thiruvananthapuram 1

Definition: : 

Definition: ECG is the graphical recording of electrical activity of human heart recorded from the body surface 2

Advantages : 

Advantages ECG is immediately available, non-invasive, inexpensive and a highly versatile tool 3

Importance : 

Importance Interpretation of the hearts electrical messages is a valuable and easily attained skill useful in diagnosis and treatment 4

Not a “Bali kera mala” : 

Not a “Bali kera mala” It is easy, provided you learn it systematically, thoroughly and practice it daily 5

Uses of ECG: : 

Uses of ECG: There are several uses of ECG in the general practice and consultant practice Heart Rate Normal / Tachycardia / Bradycardia Arrhythmias Ventricular / Supraventricular Heart Blocks AV Nodal / RBBB / LBBB Electrolyte Imbalance Hypokalemia / Hyperkalemia Carditis Myocarditis / Pericarditis Drug Effect Digoxin / Quinidine / Adriamycin Coronary Circulation Ischemia / Injury / Infarct Electrical Axis Normal / Right axis / Left axis Chamber Enlargement LAE / RAE / LVH / RVH 6

Willem Einthoven : 

Willem Einthoven It was Einthoven who discovered the ECG machine in 1890 and he was awarded Nobel Prize in the year 1924 7

ECG Machine : 

ECG Machine The ancient ECG machine - the patient dipping both hands and the left leg in buckets containing salted solution 8

Modern ECG Machine : 

Modern ECG Machine The present day ECG machines are compact, portable as well as computerized; some with multi channel recordings 9

The Principle : 

The Principle ECG Machine is a modified galvanometer in which the recordings are made by electrodes placed on the body Current moving towards +ve electrode Current moving away from +ve electrode + + Positive deflection Negative deflection 10

ECG Paper : 

ECG Paper The ECG paper is actually a black paper on which a heat sensitive, white or rose substance is coated Black paper Cheap Heat sensitive substance coated No ink 11

The Graphical Recording : 

The Graphical Recording 12

The Duration : 

The Duration The duration is measured in the horizontal direction. One small division = 1mm and eq. to 0.04 seconds 13

Conversion : 

Conversion Then 2 SD = 0.08 sec and 3SD = 0.12 sec , 4SD = 0.16sec, 5SD = 0.20sec, so on and so forth 14

Amplitude : 

Amplitude The calculation is one mille volt of current produces a deflection of 10 small divisions (sd) 15 Lead V6 16mm 6mm

Leads in ECG : 

Leads in ECG The ECG discovered by Einthoven had only one set consisting of three leads I, II & III 16

Standard Limb Leads : 

Standard Limb Leads Standard limb leads I, II and III are obtained using a +ve and -ve electrode placed on the wrists and ankles       I II III 17

Augmented Unipolar Lead aVR : 

Augmented Unipolar Lead aVR A neutral electrode is made by joining 2 limbs and an exploring electrode is placed in the 3rd limb Exploring Electrode Neutral Electrode 18

Chest Leads V1 to V6 : 

Chest Leads V1 to V6 A neutral electrode is made by connecting all 3 limbs and exploring Electrodes are then placed over chest 19

Right Chest Leads : 

Right Chest Leads Right sided leads V3R and V4R are recorded by placing electrodes on the right side of chest 20

Orientation of the leads : 

Orientation of the leads The limb leads are oriented to the frontal plane and the chest leads are oriented to the horrizontal plane 21

The Cardiac Cycle : 

The Cardiac Cycle The P, Q, R, S, T & U waves were named so by Einthoven, together they represent the events of the human cardiac cycle 22 P Q T P R S

The waves and intervals : 

The waves and intervals The waves are regrouped as P wave, QRS complex, ST segment, T wave and U wave and the intervals PR, QRS, QT 23

Electrical Correlation : 

Electrical Correlation P wave represents atrial depolarization, QRS complex - ventricular depolarization, T - ventricular repolarization 24

Now read ECG in 12 steps : 

Now read ECG in 12 steps Normally, one complex with all components p, q, r, s, t and u waves is good enough for interpretation of ECG Long leads Short leads 25

Step 1. Standardization : 

Step 1. Standardization It is the first lead of the electrocardiogram, the standard against which other leads are to be read 26

What is Standardization? : 

What is Standardization? When 1 milli volt of current is given by the machine it produces a square wave deflection of 10 small divisions 1 mV 10 sd 27 1 mV 5 sd

Look for standardization in every ECG : 

Look for standardization in every ECG The first step in reading an ECG is to look for the presence and correctness of the standardization 28

Step 1: Standardization : 

Step 1: Standardization Step 01. Std: 1mv = 10sd 29 There is a standardization lead looking like a rectangle the height was 10mm there were no half standardization leads

Step 2: Calculation of Heart rate : 

Step 2: Calculation of Heart rate If the rhythm is regular, count the number of BDs between two adjacent R waves, then divide 300 with that value 30 If RR = 1 BD, HR will be = 300/min. If RR = 2 BD, HR will be = 150/min. If RR = 3 BD, HR will be = 100/min. If RR = 4 BD, HR will be = 75/min. If RR = 5 BD, HR will be = 60/min. If RR = 6 BD, HR will be = 50/min.

Heart Rate in Irregular Rhythm : 

Heart Rate in Irregular Rhythm Count the number of QRS complexes within 6 seconds of ECG paper, then multiply by 10 to get heart rate in 60 seconds 31

Step 2: The Heart Rate : 

Step 2: The Heart Rate The rhythm is regular Counted the big divisions between two R waves Divided the number 300 with the no of big divisions The vallue is 75/mt Step 02 – Heart Rate : 75/mt 32

Step : Rhythm of the Heart : 

Step : Rhythm of the Heart Rhythm of heart is the regularity or irregularity of the heart action, studied using a long lead II or V1 33

Normal Sinus Rhythm : 

Normal Sinus Rhythm if the heart rate is between 60 and 100 and every P wave is followed by a QRS complex and a T wave and intervals normal 34

Step 3: The Rhythm : 

Step 3: The Rhythm The rhythm appeared to be regular The heart rate calculated was 75 per minute Each P was followed by a QRS and T PR interval and QRS durations were normal Step 03 – Rhythm of Heart : NSR 35

Step 4 – Electrical Axis : 

Step 4 – Electrical Axis It is the net or ultimate direction of conduction of the cardiac impulse from SA node to the ventricular apex 36

Determining Axis : 

Determining Axis By studying leads I and III alone. If the net deflection is upright in these two leads, the axis is considered as normal 37 III

Normal Electrical Axis : 

Normal Electrical Axis Lead I shows an upright wave with net positive deflection and lead III shows a net positive wave with upward deflection 38

Right Axis Deviation : 

Right Axis Deviation Lead I shows a downward wave with net negative deflection and lead III shows a net positive wave with +ve deflection 39

Left Axis Deviation : 

Left Axis Deviation Lead I shows a positive wave with net positive deflection and lead III shows a net negative wave with negative deflection 40

Step 4: Electrical Axis of Heart : 

Step 4: Electrical Axis of Heart In lead I there was a positive and negative But positive wave was more In lead I the net deflection was positive In lead III also the net deflection was positive Step 04 - Electrical Axis: Normal 41

Step 5: P wave : 

Step 5: P wave The normal P wave is upward convex in shape and prominently seen in leads II and V1 42

Normal P wave : 

Normal P wave The normal P wave is not more than 2.5 mm height and not more than 2.5 mm in width 43

P Mitrale : 

P Mitrale When P wave is broad and notched it indicates Left Atrial Enlargement and it is most often seen in RHD MS 44

P Pulmonale : 

P Pulmonale When P wave is tall and peaked it indicates Right atrial enlargement, it is most often seen in Chronic Corpulmonale 45

Step 5: P wave : 

Step 5: P wave P wave was 2 mm wide It was 2.5 mm high the shape was normal in lead II it was biphasic in V1 and terminal negative Step 05 – P wave: Normal 46

Step 6: PR Interval : 

Step 6: PR Interval The physiological neccessity, the same SA Nodal impulse has to activate, both atria & ventricles 47 PR Interval

Normal PR Interval : 

Normal PR Interval The Normal PR Interval is 3-5 small divisions; in other words it is 0.12 to 0.20 seconds 48

Prolonged PR Interval : 

Prolonged PR Interval If the PR interval is equal to or more than 0.21 sec, it is seen in Acute Rheumatic Fever and I degree HB 49

ECG showing short PR interval : 

ECG showing short PR interval It is a sinus rhythm with short PR interval and ventricular pre-excitation syndrome possibly due to WPW 50

Step 6: PR Interval : 

Step 6: PR Interval I measured the PR interval It was found to be 4 small divisions It meant that it is 0.16 seconds in duration It is with in the normal ranges Step 06 – PR interval: Normal 51

Step 7: Q Wave : 

Step 7: Q Wave Q wave is defined as the first negative deflection of the QRS Complex and it is normally present only in a few leads 52

‘No Q’ situation and “insignificant Q” : 

‘No Q’ situation and “insignificant Q” A small q may be present in some leads viz. III, II, V5 and V6; (<0.04mm in width) , then it is an isolated finding in one lead P QRS P No Q T 53 Small q

Pathological Q wave : 

Pathological Q wave It is one which is more than 0.04mm in width. It may also be more than 25% of the R wave height in the same lead P Q P Q >0.04sec 54

Why is Q very important? : 

Why is Q very important? Presence of significant Q wave indicates the diagnosis of Myocardial infarction either acute or old . 55

Step 7: Q wave : 

Step 7: Q wave Small q were present in V5 and V6 Rest of the leads were not showing any q He q present were not wide None of them > 0.04 second Step 07 – Q wave: Nil pathological 56

Step 8: QRS Duration Measurement : 

Step 8: QRS Duration Measurement From the beginning of QRS to the end of QRS, irrespective of the type and waves in the QRS 57

QRS Patterns : 

QRS Patterns QRS patterns vary from individual to individual and from lead to lead; they don’t have much significance 58

Step 8: QRS duration : 

Step 8: QRS duration QRS complexes were looking normal The duration, I measured It was 0.10 seconds The pattern were numerous Step 08 – QRS Duration: Normal 59

Step 9: ST segment : 

Step 9: ST segment ST segment is that portion of the base line from the S wave to the beginning of T wave; normally, it is iso-electric ST segment 60

ST segment elevation : 

ST segment elevation It is the elevation of its beginning from the baseline, when compared to the isoelectric line or the PR segment ST segment elevation ST segment 61

What is J point? : 

What is J point? J point is the point at which the S wave ends and the ST segment begins, usually seen as a definite point of turn J point elevation J Point 62

Significance of ST elevation : 

Significance of ST elevation It is due to myocardial injury in coronary artery disease and it is the single most important criterion of thrombolytic therapy . 63

Whether there is ST depression? : 

Whether there is ST depression? When the ST segment is depressed by1mm from the baseline, it is called ST depression Normal ST segment ST segment Depression 64

Causes of ST depression : 

Causes of ST depression Down sloping ST depression is due to ventricular strain and relative ischemia; horizontal due to absolute ischemia Down sloping ST segment depression Horizontal ST segment depression 65

Step 9: ST segment : 

Step 9: ST segment ST segments were flat and isoelectric I compared them with the P segments They were at the same level There was no point elevation or depression Step 09 – ST segment is isoelectric 66

Step 10. T wave : 

Step 10. T wave T wave is the upward convex wave following the QRS complex and it represents ventricular repolarization Normal T wave 67

What is tall peaked T wave? : 

What is tall peaked T wave? When it is very tall and equal to or more than the preceding R wave and along with an elevated ST suggestive of a acute MI Tall peaked T wave Normal T wave 68

Significance of peaked T : 

Significance of peaked T Along with ST elevation in a set of ECG leads are the earliest evidence of ACS called Hyperacute Myocardial Infarction . 69

Other cause of tall peaked T : 

Other cause of tall peaked T Peaked T, along with decreased p wave amplitude and widening of QRS complex suggest hyperkalemia . 70

Types of T wave inversion : 

Types of T wave inversion In AMI terminal portion of T is inverted ie. a biphasic T wave; In other forms of ischemia T is symmetrically inverted Symmetrical T Inversion Biphasic T wave 71

ECG with T inversions : 

ECG with T inversions ST depression and T inversions seen in leads II, III and aVF and V4, V5 and V6 suggest ischemia of inferior and lateral walls 72

Step 10: T wave : 

Step 10: T wave They were upright in all leads With the exception of leads aVR and V1 T shape was now inspected There were no peaked or inverted T waves Step 10 – T wave: Normal 73

Normal ECG : 

Normal ECG In normal persons ECG the q wave is absent or insignificant, ST isoelectric and T upright in all leads . 74

ECG changes after Acute MI : 

ECG changes after Acute MI After AMI, q wave appears, ST is elevated and the T wave is inverted in the leads affected . 75

Progressive changes during MI : 

Progressive changes during MI Seen is the normal ECG followed by changes in acute MI Peaked T, ST elevation, loss of R and T inversion 76

Progressive changes after MI : 

Progressive changes after MI The ST elevation gets resolved, T inversion gradually disappears and the Q waves if any persist 77

Anterior Wall MI : 

Anterior Wall MI Seen in the anterior chest leads, from V1 to V4 it is diagnostic; if lead V1 is involved it is termed antero-septal MI 78

Coronary Occlusion : 

Coronary Occlusion Anterior wall myocardial infarction means that the LAD branch of the left coronary artery is occluded by a thrombus 79 Thrombus

Acute Anteroseptal MI : 

Acute Anteroseptal MI ST elevation and tall peaked T waves are seen in the anterior precordial leads; no q waves have appeared 80

Antero-septal MI evolved phase : 

Antero-septal MI evolved phase ST is still elevated the T wave is upright in the chest leads V1 to V4; Q waves have appeared in the same leads 81

Lateral Wall Infarction : 

Lateral Wall Infarction Changes of Acute MI , when seen in the lateral chest leads, 1, aVL, V5 V6, is diagnostic of Lateral Wall Myocardial Infarction 82

Deep Circumflex occlusion : 

Deep Circumflex occlusion It is also inferred from this, that it is the deep circumflex branch of the left coronary artery, is occluded 83 Thrombus

Inferior Wall Infarction : 

Inferior Wall Infarction Changes of AMI, when seen in the inferior chest leads, namely II, III and aVF is diagnostic of Inferior Wall MI 84

Right coronary artery occlusion : 

Right coronary artery occlusion It is the right coronary artery, which supplies the inferior or diaphragmatic surface, is occluded 85 Thrombus

Acute Inferior Wall MI – Early stage : 

Acute Inferior Wall MI – Early stage Changes are seen in the leads II, III and aVF; hence it is Inferior wall MI; there are reciprocal changes also 86

Acute Inferior Wall MI in ECG : 

Acute Inferior Wall MI in ECG There is ST elevation, Upright and peaked waves in II, II and aVF. It is acute Inferior wall MI 87

Antero-lateral Infarction : 

Antero-lateral Infarction Changes of Acute MI are seen in all the anterior chest leads, from V1 through V6; diagnostic of Antero-lateral Wall MI 88 Thrombus Thrombus

Left Coronary Stem Occlusion : 

Left Coronary Stem Occlusion The LCA, which supplies the whole of the anterior wall of heart is occluded at the stem 89 Thrombus

True Posterior MI : 

True Posterior MI Changes are in V1 as mirror image. Tall R instead of Q, ST depression instead of ST elevation, upright T instead of T inv 90

Right Ventricular Infarction : 

Right Ventricular Infarction The changes of MI are visible in the right ventricular leads, V3R & V4R; it is a right ventricular Infarction 91

ECG of RVMI : 

ECG of RVMI Right sided leads shown separately on the right side of the panel shows ST elevation - IWMI + RV MI 92

Step 11: Right Ventricular Hypertrophy : 

Step 11: Right Ventricular Hypertrophy Normally R in V1 is <S in the same lead. If R height is found to be >S depth in lead V1 it is the voltage criteria for RVH Lead V1 Lead V1 93

Right Ventricular Hypertrophy : 

Right Ventricular Hypertrophy The height of the R wave in V1 and depth of the S wave in V1 is measured and these are compared .. 94

Step 11: RVH by voltage criteria : 

Step 11: RVH by voltage criteria Measured the height of r wave in V 1– 4 mm I looked at lead V1 again Measured the depth of S wave – 16 mm The r wave height is less than S wave depth Step 11 – No RVH by voltage criteria 95

Step 12: S in V1 + R in V6 : 

Step 12: S in V1 + R in V6 If the depth of S in V1 + R height in V6 is more than 35mm, it satisfies the voltage criteria for Left Ventricular Hypertrophy Lead V1 Lead V6 96

Left ventricular hypertrophy : 

Left ventricular hypertrophy The depth of the S in V1 is measured and added to the height of the R in V6; the total is >35 mm It is LVH 97 .

Step 12: LVH by voltage criteria : 

Step 12: LVH by voltage criteria measured the depth of S in V1 – 12 mm looked at lead V6 measured the height of R wave – 16 mm added these two. The result was 28 mm Step 12 – No LVH by voltage criteria 98

Summary : 

Summary 1. Std 2. Rate 3. Rhythm 4. Axis 5. P 6. PR 7. Q 8. QRS 9. ST 10. T 11. R/S in V1 12. SV1+RV6 99 1mv=10sd 75/mt NSR Normal 2.5X2.5 0.16sec Nil Path 0.08 Isoelectric Normal 6/16 5+20=25

Slide 100: 

100 Thank You for the Patient Listening