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Electrocardiography for Students

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ECG Simplified for Students

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Electrocardiography for Students

  1. 1. Electrocardiography<br />Dr. S. Aswini Kumar. MD<br />Professor of Medicine<br />Medical College Hospital<br />Thiruvananthapuram<br />1<br />
  2. 2. Definition:<br />ECG is the graphical recording of electrical activity of human heart recorded from the body surface using multiple electrodes placed over the body<br />2<br />
  3. 3. Advantages<br />ECG is immediately available and it is non-invasive as well as inexpensive<br />Not only that, it is a highly versatile tool<br />3<br />
  4. 4. Importance<br />Interpretation of the hearts electrical messages is a valuable and easily attained skill<br />It is useful in the diagnosis and treatment<br />4<br />
  5. 5. Not a “Bali kera mala”<br />It is easy, provided you learn it systematically and thoroughly and practice it daily<br />ECG reading is not a Bali Kera Mala.<br />5<br />
  6. 6. Uses of ECG:<br />Heart Rate<br />Normal / Tachycardia / Bradycardia<br />Arrhythmias<br />Ventricular / Supraventricular<br />Heart Blocks<br />AV Nodal / RBBB / LBBB<br />Coronary Circulation<br />Ischemia / Injury / Infarct<br />Chamber Enlargement<br />LAE / RAE / LVH / RVH<br />Electrical Axis<br />Normal / Right axis / Left axis<br />Electrolyte Imbalance <br />Hypokalemia/ Hyperkalemia<br />Carditis<br />Myocarditis/ Pericarditis<br />Drug Effect<br />Digoxin / Quinidine / Adriamycin<br />There are multiple uses of ECG in the general practice and consultant practice as well as in internal medicine<br />6<br />
  7. 7. Willem Einthoven<br />It was Einthoven who discovered the ECG machine<br />It was in 1890 and for this epoch making invention he was awarded Nobel Prize in the year 1924<br />7<br />
  8. 8. ECG Machine<br />The ancient ECG machine occupied a whole room<br />The patient dipping both hands and the left leg in buckets containing salted solution <br />8<br />
  9. 9. Modern ECG Machine<br />The present day ECG machines are very compact, portable as well as computerized<br />Some capable of producing multi channel recordings<br />9<br />
  10. 10. The Principle<br />ECG Machine is a modified galvanometer in which the recordings are made by electrodes placed on the body surface, sensing the electrical impulses of heart <br />Positive deflection<br /><ul><li>Current moving towards +ve electrode</li></ul>+<br />Negative deflection<br /><ul><li>Current moving away from +ve electrode</li></ul>+<br />10<br />
  11. 11. ECG Paper<br />The ECG paper is actually a black paper on which a heat sensitive, white or rose substance is coated<br />This coating is erased by the heated stylus <br />Black paper<br />No ink<br />Heat sensitive<br />Cheap<br />11<br />
  12. 12. The Graphical Recording<br />12<br />
  13. 13. The Duration<br />The duration is measured in the horizontal direction. <br />The calculation is, one small division is equal to 1mm and it is equivalent to 0.04 seconds<br />13<br />
  14. 14. Conversion<br />When one small division horizontally (SD) = 0.04sec<br />Then 2 SD = 0.08 sec and 3SD =0.12 sec , 4SD = 0.16sec, 5SD = 0.20sec so on and so forth<br />14<br />
  15. 15. Amplitude<br />15<br />Lead V6<br />The amplitude is measured in the vertical direction.<br />The calculation is one mille volt of current produces a deflection of 10 small divisions (sd)<br />
  16. 16. Amplitude simplified<br />However amplitude of waves in are expressed only in mm of height of or depth of the waves. <br />Here the ‘R’ wave is 16mm and ‘S’ wave is 6 mm<br />16mm<br />6mm<br />16<br />
  17. 17. Leads in ECG<br />The ECG discovered by Einthoven had only one set consisting of three leads I, II & III<br />Later three more sets were added to this<br />17<br />
  18. 18. Standard Limb Leads<br />Standard limb leads I, II and III are obtained using a +ve and -ve electrode placed on the wrists of upper limbs and ankle of the left lower limb<br /><br /><br />I<br /><br /><br />III<br />II<br /><br /><br />18<br />
  19. 19. Limb leads I, II and III<br />Originally discovered by Einthoven, when Limb leads I, II and III form a triangle named after him <br />The heart is considered to be situated in the center<br />19<br />
  20. 20. Augmented Unipolar Lead aVR<br />Exploring Electrode<br />Neutral Electrode<br />Here a neutral electrode is made by joining the left upper limb and left lower limb. <br />An exploring electrode is placed in the right upper limb<br />20<br />
  21. 21. Augmented Unipolar Lead aVL<br />Exploring Electrode<br />Neutral Electrode<br />Here a neutral electrode is made by joining the right upper limb and left lower limb<br />An exploring electrode is placed in the left upper limb<br />21<br />
  22. 22. Augmented Unipolar Lead aVF<br />Here a neutral electrode is made by joining the left upper limb and right upper limb<br />The exploring electrode is placed in the left lower limb<br />Neutral Electrode<br />Exploring Electrode<br />22<br />
  23. 23. Chest Leads V1 to V6<br /> Neutral electrode is made by connecting all 3 limbs<br />Exploring Electrodes are then placed over various points on left side of the chest to record the chest leads <br />23<br />
  24. 24. Right Chest Leads<br />Right sided leads V3R and V4R can recorded by placing electrodes on the right chest <br />They correspond to leads V3 and V4 on the left sides<br />24<br />
  25. 25. Higher Chest Leads<br />Higher Chest leads HC1 and HC2 may be recorded by placing electrodes one space above the chest leads. <br />This is to map the higher level of cardiac activity<br />25<br />
  26. 26. The Cardiac Cycle<br />The P, Q, R, S, T & U waves were named so by Einthoven. <br />Together they represent the sequence of events of the human cardiac cycle<br />26<br />
  27. 27. The waves and intervals<br />The waves are regrouped as P wave, QRS complex, ST segment, T wave and U wave. <br />The intervals of importance are PR, QRS, QT & RR <br />27<br />
  28. 28. Electrical Correlation<br />P wave represents atrial depolarization, QRS complex - ventricular depolarization, T - ventricular repolarization; <br />Atrial repolarization is hidden within PR or QRS<br />28<br />
  29. 29. Measurements<br />The measurements required are the duration of P wave, PR interval, ST segment, T wave height, <br />The RR interval, QRS duration and QT interval <br />29<br />
  30. 30. Long leads<br />Short leads<br />Long leads<br />Normally, one complex with all components p, q, r, s, t and u waves is good enough for interpretation of ECG<br />But for assessment of arrhythmias one needs long lead <br />30<br />
  31. 31. Step 1. Standardization<br />It is the first lead of the electrocardiogram, the standard against which other leads are to be read<br />It is the square waves seen at the beginning of the ECG<br />31<br />
  32. 32. What is Standardization?<br /> 10 small divisions<br /> 1 mV current<br />When 1 milli volt of current is given by the machine it produces a square wave deflection of 10 small divisions<br />When ECG is recorded this amplitude is applied<br />32<br />
  33. 33. What is half standardization?<br /> 5 small divisions<br /> 1 mV current<br />Here even when 1 milli volt of current is applied there is a deflection of only five small divisions<br />This is made so, if the deflections are very tall<br />33<br />
  34. 34. Look for standardization in every ECG<br />So the first step in reading an ECG is to look for the presence and correctness of the standardization<br />Only if it is so, the rest of the ECG is read<br />34<br />
  35. 35. Step 1: Standardization<br />Step 01. Standardization: 1mv = 10sd<br />35<br />I looked into the ECG<br />I found that there is a standardization lead<br />It was looking like a rectangle<br />The height was 10mm<br />There were no half standardization leads<br />
  36. 36. Step 2: Calculation of Heart rate<br />If the rhythm is regular, count the number of big divisions between two adjacent R waves<br /> Then divide the 300 with that value to get the heart rate<br />36<br />
  37. 37. Rest of it is calculated mentally<br />If RR = 1 BD, HR will be = 300/min. <br />If RR = 2 BD, HR will be = 150/min. <br />If RR = 3 BD, HR will be = 100/min. <br />If RR = 4 BD, HR will be = 75/min. <br />If RR = 5 BD, HR will be = 60/min. <br />If RR = 6 BD, HR will be = 50/min. <br />Only this amount of accuracy in calculating the heart rate is required in most instances<br />Otherwise divide 1500 by the number of small divisions<br />37<br />
  38. 38. Heart Rate in Irregular Rhythm<br />If there is Atrial Fibrillation, count the number of QRS complexes within 6 seconds of ECG paper <br />Then multiply by 10 to get heart rate in 60 seconds<br />38<br />
  39. 39. Step : Rhythm of the Heart<br />Rhythm of heart is the regularity or irregularity of the heart action<br />It has to be studied using a long lead II or V1<br />39<br />
  40. 40. Normal Sinus Rhythm<br />Normal sinus rhythm is said to be present 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<br />40<br />
  41. 41. Step 3: The Rhythm <br />The rhythm appeared to be regular<br />The heart rate calculated was 75 per minute<br />Each P was followed by a QRS and T<br />PR interval and QRS durations were normal<br />The shape of QRS was normal<br />Step 02 - Heart Rate: 75/min<br />41<br />
  42. 42. Step 4 – Electrical Axis<br />It is the net or ultimate direction of conduction of the cardiac impulse from SA node to the ventricular apex which can be represented as a straight line vector<br />42<br />
  43. 43. Determining Axis<br />Axis is determined by studying leads I and III alone. If the net deflection is upright in these two leads, the axis is considered as normal<br />I II<br />43<br />
  44. 44. Normal Electrical Axis<br />In the above ECG the lead I shows an upright wave with net positive deflection and lead III shows a net positive wave with upward deflection. Hence axis is normal<br />44<br />
  45. 45. Right Axis Deviation<br />In the above ECG the lead I shows a downward wave with net negative deflection and lead III shows a net positive wave with +ve deflection. Hence axis is RIGHT<br />45<br />
  46. 46. Left Axis Deviation<br />The lead I shows a positive wave with net positive deflection and lead III shows a net negative wave with negative deflection. Hence axis is LEFT<br />46<br />
  47. 47. Step 4: Electrical Axis of Heart<br />I looked into leads ! And III<br />In lead I there was a positive and negative<br />But positive wave was more<br />In lead I the net deflection was positive<br />In lead III also the net deflection was positive<br />Step 04 - Electrical Axis: Normal<br />47<br />
  48. 48. Step 5: P wave<br />The normal P wave is upward convex in shape and prominently seen in leads II and V1<br />So look into leads II and V1 for the details<br />48<br />
  49. 49. Normal P wave<br />The normal P wave is not more than 2.5 mm height and not more than 2.5 mm in width<br />If it more than this it is abnormal<br />49<br />
  50. 50. P Mitrale<br />When P wave is broad and notched it indicates Left Atrial Enlargement and it is most often seen in patients with Rheumatic Mitral Stenosis<br />50<br />
  51. 51. P Pulmonale<br />When P wave is tall and peaked it indicates Right atrial enlargement<br />It is most often seen in Chronic Corpulmonale<br />51<br />
  52. 52. Step 5: P wave<br />I studied the P wave dimensions<br />It was 2 mm wide<br />It was 2.5 mm high<br />P wave shape was normal in lead II<br />P was biphasic in V1 and terminal negative<br />Step 05 – P wave: Normal<br />52<br />
  53. 53. Step 6: PR Interval<br />The physiological necessity, for the AV Nodal delay, which causes the normal PR interval is that, the same SA Nodal impulse has to activate, both atria & ventricles<br />53<br />
  54. 54. Normal PR Interval<br />The Normal PR Interval is 3-5 small divisions, when measured from the beginning of P to beginning of QRS <br />In other words it is 0.12 to 0.20 seconds<br />54<br />
  55. 55. Prolonged PR Interval<br />Prolonged PR interval is said to be present if the PR interval is equal to or more than 0.21 sec<br />It is seen in Acute Rheumatic Fever and I degree HB<br />55<br />
  56. 56. Short PR Interval<br />PR interval is said to be short when it is less than 0.12 seconds in duration<br />It is seen in WPW Syndrome and Junctional Rhythm<br />56<br />
  57. 57. ECG showing short PR interval<br />It is a sinus rhythm with short PR interval and ventricular pre-excitation syndrome possibly due to WPW<br />There is in addition a Delta wave<br />57<br />
  58. 58. Step 6: PR Interval<br />I looked at the PR segment<br />I measured the PR interval<br />It was found to be 4 small divisions<br />It meant that it is 0.16 seconds in duration<br />It is with in the normal ranges<br />Step 06 – PR interval: Normal<br />58<br />
  59. 59. Step 7: Q Wave<br />Q wave is defined as the first negative deflection of the QRS Complex and it is normally present only in a few leads viz. Lead III, II, V5 & V6 and they are very small<br />59<br />
  60. 60. There can be ‘no Q’ situation<br />But q waves are not always present in all the leads of all persons, unlike the other waves<br />A small q may be present in some leads <br />No Q<br />Q<br />T<br />P<br />P<br />QRS<br />P<br />T<br />P<br />QRS<br />60<br />
  61. 61. Significance of Q waves<br />The presence of a significant Q wave is highly suggestive of a transmural myocardial infarction<br />It also means that the coronary artery is totally occluded<br />61<br />
  62. 62. What is an insignificant ‘Q wave’?<br />When the ‘q wave’ is very small in size (less than 0.04mm in width) it is called an insignificant q wave<br />Then it is an isolated finding in one lead. <br />Small q<br />62<br />
  63. 63. Small or insignificant q waves are seen usually in leads III, II, V5 and V6, in normal persons. Rest of the leads in a normal person does not show any significant q wave<br />In which leads small ‘q’ waves are seen?<br />Lead III<br />Lead II<br />Lead V5<br />Lead V6<br />63<br />
  64. 64. Pathological Q wave<br />A ‘significant Q’ or ‘pathological Q’ 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<br />&gt;0.04mm<br />P<br />Q<br />P<br />Q<br />64<br />
  65. 65. Why is Q very important?<br />Presence of significant Q wave indicates the diagnosis of Myocardial infarction either acute or old<br />It is usually preceded by the classical chest pain<br />.<br />65<br />
  66. 66. Whether Acute MI or Old MI?<br />If it is, accompanied by other evidence of acute Myocardial Infarction, like ST elevation or T wave inversion it is acute; otherwise it is old<br />.<br />66<br />
  67. 67. Anterior wall Infarction<br />In Anterior wall Myocardial Infarction the changes of MI are seen in V2-V4<br />If V1 also shows changes the septum is involved<br />67<br />
  68. 68. Inferior wall Infarction<br />In Inferior Wall Myocardial Infarction the changes of MI are seen in II, III and aVF<br />If V1 also shows changes the septum is involved<br />.<br />68<br />
  69. 69. Step 7: Q wave<br />I looked for any q waves<br />Small q were present in V5 and V6<br />Rest of the leads were not showing any q<br />He q present were not wide<br />None of them &gt; 0.04 second<br />Step 07 – Q wave: Nil pathological<br />69<br />
  70. 70. QRS Duration Measurement<br />QRS duration is measured from the beginning of QRS to the end of QRS<br />Irrespective of the type and waves in the QRS<br />70<br />
  71. 71. QRS Patterns<br />QRS patterns vary from individuall to individual and from lead to lead<br />They don’t have much significance<br />71<br />
  72. 72. Step 8: QRS duration<br />I looked at the QRS complexes<br />They were looking normal<br />The duration, I measured<br />It was 0.10 seconds<br />The pattern were numerous <br />Step 08 – QRS Duration: Normal<br />72<br />
  73. 73. Step 8: ST segment<br />ST segment is that portion of the base line from the S wave to the beginning of T wave, Normally, it is iso-electric ie. at the same level as that of the baseline<br />ST segment<br />73<br />
  74. 74. ST segment elevation<br />ST segment elevation is the elevation of the beginning of ST segment from the baseline, when compared to the isoelectric line or the PR segment<br />ST segment elevation<br />ST segment<br />74<br />
  75. 75. What is J point?<br />J point is the point at which the S wave ends and the ST segment begins<br />It is usually seen as a definite point of turn<br />J point elevation<br />J Point<br />75<br />
  76. 76. Significance of ST elevation<br />Elevation of the ST segment is considered to be due to myocardial injury in coronary artery disease and it is the single most important criterion of thrombolytic therapy<br />76<br />
  77. 77. Pathophysiological Co-relation<br />The degree of ST elevation in the ECG directly correlates with the pathophysiology of CAD<br />Hence it the indication for thrombolysis<br />77<br />
  78. 78. Differential diagnosis of ST elevation<br />Pericarditis is characterized by the presence of ST elevation with upward concavity, present almost in all the leads and associated with PR segment depression<br />78<br />
  79. 79. Early Repolarization<br />It is a normal variant seen mostly in young males characterized by J point elevation<br />To be differentiated from Acute MI and Pericarditis<br />79<br />
  80. 80. Comparison of ECG changes<br />ST/T Ratio in V6 of &lt;0.25 against Pericarditis and less ST(equal to or less than 0.05mV) against Acute Myocardial Infarction<br />80<br />
  81. 81. Whether there is ST depression?<br />The ST segment is normally at the same level as that of the iso-electric line/PR segment. When it is depressed by1mm from the baseline, it is called ST depression<br />Normal ST segment<br />ST segment Depression<br />81<br />
  82. 82. What is ST depression due to?<br />ST depression in ECG is due to the presence of Ischemia to the myocardium<br />It occurs in Angina<br />82<br />
  83. 83. What is myocardial Ischemia?<br />Myocardial ischemia may result in temporary or permanent damage to the myocardium<br />But usually not<br />83<br />
  84. 84. Causes of ST depression<br />Down sloping ST elevation is usually due to ventricular strain associated with a relative ischemia, whereas, horizontal ST depression is due to absolute ischemia<br />Horizontal ST segment depression<br />Down sloping ST segment depression<br />84<br />
  85. 85. Step 9: ST segment<br />I looked at the ST segment after each QRS<br />They were flat and isoelectric<br />I compared them with the P segments<br />They were at the same level<br />There was no point elevation or depression<br />Step 09 – ST segment is isoelectric<br />85<br />
  86. 86. Step 10. T wave<br />T wave is the upward convex wave following the QRS complex and it represents ventricular repolarization<br />Normal T wave<br />86<br />
  87. 87. Normal T wave<br />The normal pattern of T wave is upward and convex in all the leads of the ECG except aVR and V1 ; it is inverted in these leads<br />87<br />
  88. 88. What is tall peaked T wave?<br />T wave is said to be tall and peaked 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<br />Tall peaked T wave<br />Normal T wave<br />88<br />
  89. 89. Significance of peaked T<br />Tall and peaked T waves along with ST elevation in a set of ECG leads are the earliest evidence of acute coronary syndrome called Hyperacute Myocardial Infarction<br />89<br />
  90. 90. Other important cause of tall peaked T<br />Peaked T, along with decreased p wave amplitude and widening of QRS complex suggest hyperkalemia<br />It is also a potentially fatal disorder<br />90<br />
  91. 91. Types of T wave inversion<br />In Acute MI the terminal portion of the peaked T wave is inverted resulting in a biphasic T wave; In other forms of ischemia the T wave is usually symmetrically inverted <br />Symmetrical T Inversion<br />Biphasic T wave<br />91<br />
  92. 92. ECG with T inversions<br />ST depression along with T wave inversions are seen in leads II, III and aVF and the chest leads V4, V5 and V6 suggesting ischemia of the inferior and lateral walls<br />92<br />
  93. 93. Step 10: T wave<br />I looked at the T wave in all leads<br />They were upright in all leads<br />With the exception of leads aVR and V1<br />T shape was now inspected<br />There were no peaked or inverted T waves<br />Step 10 – T wave: Normal<br />93<br />
  94. 94. Changes occurring in Acute MI<br />In normal persons ECG the q wave is absent or insignificant, ST isoelectric and T upright in all leads<br />There is no evidence of MI<br />94<br />
  95. 95. ECG changes after Acute MI<br />After Acute Myocardial Infarction, q wave appears, ST is elevated and the T wave is inverted in the leads affected<br />The evidence of MI<br />95<br />
  96. 96. Progressive changes during MI<br />Seen is the normal ECG followed by the progressive changes in acute myocardial infarction<br />Peaked T, ST elevation, loss of R and T inversion<br />96<br />
  97. 97. Progressive changes after MI<br />ECG changes in the post MI periodThe ST elevation gets resolved, T inversion gradually disappears and the Q waves if any persist<br />97<br />
  98. 98. Anterior Wall MI<br />Changes of Acute MI , when seen in the anterior chest leads, from V1 to V4 it is diagnostic of Anterior Wall MI; if lead V1 is involved it is termed anteroseptal MI<br />98<br />
  99. 99. Coronary Occlusion<br />Anterior wall myocardial infarction means that the left anterior descending branch of the left coronary artery is occluded by a thrombus<br />99<br />
  100. 100. Acute Anteroseptal MI<br />ST elevation and tall peaked T waves are seen in the anterior precordial leads<br />No q waves have appeared<br />100<br />
  101. 101. Antero-septal MI evolved phase<br />Here the ST is still elevated the T wave is upright in the chest leads V1 to V4<br />Q waves have appeared in the same leads<br />101<br />
  102. 102. Lateral Wall Infarction<br />Changes of Acute MI , when seen in the lateral chest leads, from 1, aVL, V5 V6, it is diagnostic of Lateral Wall Myocardial Infarction<br />102<br />
  103. 103. Deep Circumflex occlusion<br />It is also inferred from this, that it is the deep circumflex branch of the left coronary artery, is occluded, either by a plaque or thrombus<br />103<br />
  104. 104. Acute Myocardial Infarction<br />Diffuse ST elevation with reciprocal changes<br />Anterior lateral and inferior walls are involved and there is atrial fibrillation also <br />104<br />
  105. 105. Inferior Wall Infarction<br />Changes of Acute Myocardial Infarction, when seen in the inferior chest leads, namely II, III and aVF is diagnostic of Inferior Wall MI<br />105<br />
  106. 106. Right coronary artery occlusion<br />It is also inferred from this, that it is the right coronary artery, which supplies the inferior or diaphragmatic surface, is occluded, either by a plaque or thrombus<br />106<br />
  107. 107. Acute Inferior Wall MI – Early stage<br />Changes are seen in the leads II, III and aVF; hence it is Inferior wall MI<br />There is ST elevation and reciprocal changes also<br />107<br />
  108. 108. Acute Inferior Wall MI in ECG<br />There is ST elevation, Upright and peaked waves in II, II and aVF<br />It is acute Inferior wall MI<br />108<br />
  109. 109. Antero-lateral Infarction<br />Changes of Acute MI are seen in all the anterior chest leads, from V1 through V6<br />It is diagnostic of Antero-lateral Wall MI<br />109<br />
  110. 110. Left Coronary Stem Occlusion<br />The left coronary artery, which supplies the whole of the anterior wall of heart is occluded at the stem, involving the area supplied by both the branches<br />110<br />
  111. 111. True Posterior MI<br />Changes are in the V1 lead of ECG as mirror image. These are Tall R instead of Q, ST depression instead of ST elevation and upright T instead of T inversion<br />111<br />
  112. 112. Right Ventricular Infarction<br />The changes of myocardial infarction are visible in the right ventricular leads, V3R & V4R<br />It is a right ventricular Infarction<br />112<br />
  113. 113. ECG of RVMI<br />Right sided leads shown separately on the right side of the panel shows ST elevation<br />The diagnosis is Inferior Wall MI + RV MI<br />113<br />
  114. 114. Transmural and subendocardial<br />Previously, abnormal Q waves were considered to be markers of trans-mural MI, while sub-endocardial infarcts were thought not to produce Q waves<br />114<br />
  115. 115. Q waves are more important<br />Now we know that Trans-mural Infarcts may occur without presence of Q waves and subendocardial infarcts may produce Q waves<br />115<br />
  116. 116. ECG in ACS<br />When a patient presents with acute onset of chest pain, ECG is the first line of investigation<br />Depending upon ECG findings further assessment made<br />116<br />
  117. 117. Acute Coronary Syndrome<br />The algorithmic management of a patient with Acute Coronary Syndrome is also now based on the ECG<br />Cardiac markers assist the diagnosis<br />117<br />
  118. 118. Step 11: Right Ventricular Hyprtrophy<br />Normally the R wave in lead V1 is less than S wave in the same lead. If R wave height is found to be more than S wave depth in lead V1 it is the voltage criteria for RVH<br />Lead V1<br />Lead V1<br />118<br />
  119. 119. Right Ventricular Hypertrophy<br />The height of the R wave in V1 and depth of the S wave in V1 is measured and these are compared<br />The R wave in V1 is taller than the S wave in V1<br />119<br />
  120. 120. Step 11: RVH by voltage criteria<br />I looked at lead V1<br />Measured the height of r wave – 4 mm<br />I looked at lead V1 again<br />Measured the depth of S wave – 16 mm<br />The r wave height is less than S wave depth<br />Step 11 – No RVH by voltage criteria<br />120<br />
  121. 121. Step 12: S in V1 + R in V6<br />If the depth of S wave in lead V1 + R wave height in V6 is more than 35mm, it satisfies the voltage criteria for Left Ventricular Hypertrophy<br />Lead V1<br />Lead V6<br />121<br />
  122. 122. Left ventricular hypertrophy<br />The depth of the S wave in V1 is measured and added to the height of the R wave in V6<br />The total is more than 35 mm It is LVH<br />122<br />
  123. 123. Step 12: LVH by voltage criteria<br />I looked at lead V1<br />Measured the depth of S wave – 12 mm<br />I looked at lead V6<br />Measured the height of R wave – 16 mm<br />Added these two. The result was 28 mm<br />Step 12 – No LVH by voltage criteria<br />123<br />
  124. 124. Thus ECG is read simply<br />1. Std<br />2. Rate<br />3. Rhythm<br />4. Axis<br />5. P <br />6. PR<br />7. Q<br />8. QRS<br />9. ST<br />10. T<br />11. R/S in V1<br />12. SV1+RV6<br />124<br />
  125. 125. 125<br />Thank You for the Patient Listening<br />

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