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ECG Interpretation
- 1. ECG INTERPRETATION Dr SalehAhmed MD Phase A, Cardiology NICVD, Dhaka
- 2. CONDUCTIVE SYSTEM There are5 specialized tissues called conductive system of the heart. These are: • SA node. • AV node. • Bundle of His. • Right bundle branch (RBB) and left bundle branch (LBB). • Purkinje fibers.
- 3. Bundle of his Purkinjefibers
- 4. ELECTROCARDIOGRAM • It isthe graphical representation of electrical potentials produced when the electric current passes through the heart. • Electrical activity is the basic characteristic of heart and is the stimulus for cardiac contraction
- 6. P wave Atrialdepolarization. PR interval The time taken for the cardiac impulse to spread over the atrium and through AV node and His- Purkinje system QRS Complex Ventricular depolarization. T wave Ventricular repolarization.
- 7. Waves of ECG Pwave Height ≤2.5mm Width ≤2.5mm Q wave Depth <2mm Width <1mm R wave aVL <13mm aVF <20mm V5,V6 <25mm QRS complex Width <3mm T wave Standard lead ≤5mm Chest lead ≤10mm
- 8. Intervals of ECG PRinterval 0.12 to 0.20 sec (3- 5mm) QT interval 0.35 to 0.43 seconds
- 9. In a normalECG recording, there are 12 leads: • 3 bipolar standard leads (LI, LII, LIII ) • 3 unipolar limb leads (aVR, aVL, aVF) • 6 chest leads (V1, V2, V3, V4, V5, V6)
- 10. VIEW OF THEHEART IN ALL LEADS V1 and V2 Right ventricle V3 and V4 Interventricular septum V5 and V6 Left ventricle V1 to V6 Anterior aspect of heart LI, aVL, V1 to V6 Extensive anterior aspect of heart or anterolateral LI, aVL, V5 and V6 Lateral LI and aVL High lateral LII, LIII and aVF Inferior aspect of heart
- 11. ECG Paper Paper Speed– 25mm/s
- 12. SYSTEMATIC APPROACH INECG INTERPRETATION •Rate—what is the rate ? • Rhythm—regular or irregular, regularly followed by occasional irregular. • Characters of individual waves (P, PR, Q, R, QRS, ST, T, U). • Specific pathological changes.
- 13. Heart Rate Whenthe cardiac rhythm is regular: • If large square is calculated • If small square is calculated:
- 14. When therhythm is irregular: 1. Count the number of R in 30 large squares 2. Then simply multiply this by 10
- 15. RHYTHM OF HEART •If the RR interval is equal, it is called regular rhythm. • If the RR interval is irregular, then it is called irregular rhythm
- 16. Causes of IrregularRhythm 1. Physiological: Sinus arrhythmia. 2. Pathological: • Atrial fibrillation. • Atrial flutter. • Ectopic beat. • SA block or sinus arrest. • Atrial tachycardia with block. • Second degree heart block. • Ventricular fibrillation.
- 17. CARDIAC AXIS • Normalaxis is between –30° to +90° Tall R in both LI andLII Axis is normal Tall R in LI and deep S in LII Left axis deviation Tall R in LII and deep S in LI Right axis deviation
- 18. LOW VOLTAGE ECG Normalstandardization 10 mm in height CRITERIA OF LOW VOLTAGE TRACING • In standard limb leads—QRS < 5 mm (mainly R wave). • In chest leads—QRS < 10 mm (mainly R wave)
- 19. CAUSES OF LOWVOLTAGE ECG TRACING • Incorrect standardization (i.e. if < 10 mm). • Obesity. • Emphysema • Pericardial effusion. • Chronic constrictive pericarditis. • Myxedema. • Hypothermia.
- 20. ECG Changes inDifferent Diseases
- 21. LEFT VENTRICULAR HYPERTROPHY •S in V1 + R in V6 or V5 > 35 mm • R in V5 or V6 > 26 mm • R in aVL > 11 mm • R in aVF > 20 mm • Left axis deviation S in V2 + R in V5 > 35 mm
- 22.
- 23. RIGHT VENTRICULAR HYPERTROPHY •Tall R wave in V1 > 7 mm • Right axis deviation
- 24.
- 25. LEFT ATRIAL HYPERTROPHY •P > 2.5 small squares • P may be notched or bifid (like M), called P mitrale • P in V1-Biphasic
- 26.
- 27. RIGHT ATRIAL HYPERTROPHY •P > 2.5 mm (P pulmonale) • P in V1 Biphasic
- 28.
- 29. ATRIAL FIBRILLATION • Pwave Absent • P may be replaced by fibrillary f wave • Rhythm: Irregularly irregular
- 30.
- 31. ATRIAL FLUTTER • Pis saw toothed appearance (flutter or F wave) • RR regular or irregular when there is variable block
- 32. P saw toothedappearance R-R regular
- 33. • A Saw toothappearance 7:1 4:1 Atrial Flutter with variable block
- 34. SUPRAVENTRICULAR TACHYCARDIA • P—absent. •QRS—narrow. • Rhythm—regular. • Trachycardia
- 35. P absent Rhythmregular Trachycardia
- 36. VENTRICULAR ECTOPIC • P—absent. •QRS—wide > 0.12 second (3 small squares). • T—opposite to major deflection. P absent Wide QRS T opposite to major deflation
- 37. • Bigeminy —every other beat is a ventricular ectopic • Trigeminy — every third beat is a ventricular ectopic
- 38. VENTRICULAR TACHYCARDIA • Pwave—absent • QRS—broad , abnormal or bizarre pattern • Rate > 100 beats /minute
- 39. Broad bizzare QRScomplex Absent P wave Heart rate >100b/min
- 40. VENTRICULAR FIBRILLATION • Chaoticirregular deflections of varying amplitude • No identifiable P waves, QRS complexes, or T waves Irregular deflaction
- 41. FIRST DEGREE AVBLOCK • PR interval—prolonged > 0.22 second
- 42. SECOND DEGREE AVBLOCK • Second degree AV block may be of 2 types: • Mobitz type I (Wenckebach’s phenomenon). • Mobitz type II.
- 43. MOBITZ TYPE I •Progressive lengthening of PR interval followed by absent QRS complex Drop Beat PR interval lengthening
- 44. MOBITZ TYPE II •Some P waves are not followed by QRS complexes • PR interval is constant Drop beat PR constant
- 45. COMPLETE HEART BLOCK •PP interval—constant • RR interval- constant • No relationship between P wave and QRS complex P P P P P PR R R
- 46. RIGHT BUNDLE BRANCHBLOCK • RSR’—in V1 and V2 (M pattern). • QRS complex— wide (3 small squre) RSR’ QRS wide
- 47. LEFT BUNDLE BRANCHBLOCK • RSR’—in V5 and V6, also in LI and aVL (M pattern). • QRS—wide (3 small squares) RSR’ QRS wide
- 48. MYOCARDIAL INFARCTION Criteria foracute myocardial infarction: Rise of Troponin I with at least one of the following: 1. Symptoms of myocardial ischaemia 2. New ischaemic ECG changes 3. Development of pathological Q waves 4. Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality 5. Identification of a coronary thrombus by angiography or autopsy (Fourth universal definition of myocardial infarction (2018),ESC)
- 49. ECG Criteria ofAcute MI • ST elevation (with upward convexity). • Pathological Q wave. • T inversion
- 50. Masurement of STelevation All lead accept V2-V3 ≥1mm V2-V3 Men ≥40 years ≥2mm <40 years ≥2.5mm Women ≥1.5mm Fourth universal definition of myocardial infarction (2018),ESC
- 51. Sites of MyocardialInfarction is Detected in Different Leads Anteroseptal MI V1 to V3 or V4 Anterior MI V1 to V6. Extensive anterior MI L1, aVL, V1 to V6. Lateral MI L1, aVL, V5, V6 High lateral L1 and aVL Inferior MI L2, L3 and aVF Right ventricular infarction V3R to V6R Posterior (true) MI V1 and V2
- 52. Artery involve inMI Inferior MI Anterior MI Lateral MI RCA LCX LAD
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- 57. Right Ventricular Infarction Whensuspect • ST elevation in V1 • ST elevation in lead III > lead II ST elevation L3>L2
- 59.
- 60. Posterior Myocardial Infarction •Posterior MI is suggested by the following changes in V1-3: • Tall, broad R waves (>30ms) • Horizontal ST depression • Upright T waves
- 61. Horizontal ST depressionTallR Upright T
- 62.
- 63. • ST elevationin V7-V9 >0.5 mm diagnostic for Posterior MI
- 64. Old Myocardial Infarction •Pathological Q wave. • ST—in baseline. • T—normal or inverted
- 65.
- 66. Acute Pericarditis • WidespreadST elevation with upward concavity (chair shaped or saddle shaped) • PR depression ST PR
- 67.
- 68. PERICARDIAL EFFUSION • Lowvoltage ECG • Tachycardia • Electrical alternans • T inversion
- 69.
- 70. HYPOKALEMIA • Prolonged PRinterval • U—prominent in chest leads . • ST depression • T is small or inverted U T
- 71.
- 72. HYPERKALEMIA • T—tall, peakedand tented (in chest leads). • P—wide, small, ultimately absent. • PR interval—prolonged. • QRS—wide, slurred and bizarre.
- 73. Tall peaked T Broadbizzare QRS
- 74. DEXTROCARDIA • Right axisdeviation • Positive QRS complexes in aVR • Absent R-wave progression in the chest leads ,dominant S waves throughout
- 75. aVR-Positive QRS complex Absentof R wave progression
- 76. PULMONARY EMBOLISM • Sinustachycardia • RBBB • Right axis deviation • S in LI, Q and T inversion in LIII (SI, QIII, TIII pattern) • ST depression and T wave inversion in right precordial leads (V1 and V2)
- 77. S wave Q wave Tinversion RBBB
- 78. Pulmonary Hypertension • Ppulmonale • RV1>7mm • Right axis deviation • RBBB
- 79.