The document provides an overview of electrocardiogram (ECG) interpretation including basics of normal ECG features, measurements of intervals, axis determination, identification of chamber enlargement, types of heart blocks, signs of ischemic heart disease, ectopic beats, tachyarrhythmias, bradyarrhythmias, and other common ECG abnormalities. It describes the typical appearance of P, QRS, and T waves as well as the durations of normal intervals and how to assess cardiac axis. It also outlines characteristics of atrial and ventricular enlargement, various grades of atrioventricular block, bundle branch blocks, ischemic changes, premature beats, tachycardias, bradycardic rhythms, and effects of electroly

1. BASICS OF E C G INTERPRETATION

2. NORMAL E C G RATE: 60 – 100/ mts MECHANISM: SINUS (P wave precedes QRS) RHYTHM: REGULAR HEART RATE: 300/ NO OF LARGE BOXES BETWEEN TWO SUCCESSIVE QRS COMPLEXES OR 1500/ NO OF SMALL SQUARES BETWEEN TWO SUCCESSIVE QRS COMPLEXES

3. E C G: NORMAL WAVES AND INTERVALS P WAVE: ATRIAL DEP QRS COMPLEX: VENTRICULAR DEP T WAVE: VENTRICULAR REP U WAVE PR INTERVAL QT INTERVAL

4. E C G: DURATION OF NORMAL WAVES AND INTERVALS P WAVE: < 0.12s WIDTH / HEIGHT PR INTERVAL: 0.12s TO 0.2s QRS COMPLEX:<0.12s QT INTERVAL:0.35-0.43s VAT :<0.04s

5. E C G: DURATION OF NORMAL WAVES AND INTERVALS Q-T INTERVAL Measured In A Lead With Initial q Wave. Measured From Beginning Of q Wave To End Of T Wave. Shortens With Tachycardia And Lengthens With Bradycardia. Q-T Interval Is Corrected For Rate Of 60, Using Bazett ’s Formula.

6. E C G: AXIS DEF : DIRECTION OF MAXIMUM DEP FRONT NORMAL AXIS: -30 to +110 LEFT AXIS: -30 to -90 RIGHT AXIS: +110 to -1 NORTH WEST AXIS: -90 to -180

7. HOW TO LOOK FOR AXIS? METHOD 1: SELECT A LEAD WITH MAXIMUM QRS , AXIS WILL BE TOWARDS THIS LEAD. METHOD 2: SELECT A LEAD WITH EQUIPHASIC QRS, AXIS WILL BE AT 90 º TO THIS LEAD. METHOD 3: IF TWO LEADS HAVE QRS OF SAME HEIGHT, AXIS WILL BE BETWEEN TWO SUCH LEADS.

8. E C G : CHAMBER ENLARGEMENT

9. E C G: CHAMBER ENLARGEMENT RT ATRIAL ENLARGEMENT : `P`pulmonale –P wave height>2.5mm LT ATRIAL ENLARGEMENT : `P`mitrale -P wave width >2.5mm Notched P wave BIATRIAL ENLARGEMENT : Biphasic P wave in V 1 Morris index : P wave depth >2 mm and duration >0.04 s of terminal deflection, suggests LT atrial enlargement

10. E C G: CHAMBER ENLARGEMENT ATRIAL ENLARGEMENT

11. E C G: CHAMBER ENLARGEMENT ATRIAL ENLARGEMENT

12. E C G: CHAMBER ENLARGEMENT RT VENTRICULAR ENLARGEMENT: R wave >7mm in V 1 , R/S ratio in V 1 >1 R in V 1 + S in V 6 >11mm LT VENTRICULAR ENLARGEMENT: R in V 6 = R in V 5 ; R in V 6 >20mm S in V 1 >30mm ; R in V 6 + S in V 1 >35mm Romhilt -Estes Score >5

13. E C G: CHAMBER ENLARGEMENT VENTRICULAR ENLARGEMENT

14. E C G: CHAMBER ENLARGEMENT RT & LT VENTRICULAR ENLARGEMENT

15. E C G : HEART BLOCKS

16. E C G:HEART BLOCKS TYPES: S A BLOCK A V BLOCK:1 º A V BLOCK 2 º A V BLOCK (Wenckebach,Mobitz ,2:1 block ) 3 º A V BLOCK( complete block) BUNDLE BRANCH BLOCK ( Rt and Lt ) FASCICULAR BLOCK (Rt and Lt )

17. E C G: HEART BLOCKS A V BLOCK: 1 º HEART BLOCK

18. E C G: HEART BLOCKS A V BLOCK:2 º HEART BLOCK ( Wenckebach Type)

19. E C G: HEART BLOCKS A V BLOCK: 2 º HEART BLOCK (Mobitz Type)

20. E C G:HEART BLOCKS A V BLOCK:2 º HEART BLOCK (2:1Block)

21. E C G: HEART BLOCKS A V BLOCK: 3 º HEART BLOCK (Complete Heart Block)

22. E C G: HEART BLOCKS RT BUNDLE BRANCH BLOCK

23. E C G: HEART BLOCKS RT BUNDLE BRANCH BLOCK

24. E C G: HEART BLOCKS LT BUNDLE BRANCH BLOCK

25. E C G: HEART BLOCKS LT BUNDLE BRANCH BLOCK

26. E C G: HEART BLOCKS RT & LT BUNDLE BRANCH BLOCK

27. E C G : ISCHEMIC HEART DISEASE

28. E C G: ISCHEMIC HEART DISEASE TYPES OF CHANGES: ISCHEMIA INJURY NECROSIS

29. E C G: ISCHEMIC HEART DISEASE

30. E C G: ISCHEMIC HEART DISEASE LEAD GROUPS Anterior: V 1 - V 6 Septal: V 3 – V 4 Lateral: I, aVL, V 5 , V 6 High Lateral: I, aVL Inferior: II, III, aVF Posterior: Mirror Image In V 1 , V 2

31. I H D: ISCHEMIA ANGINA

32. I H D: MI(SUB ENDOCARDIAL)

33. I H D: MI( INFERIOR )

34. I H D:MI(ANTERIOR)

35. E C G : EXTRASYSTOLES

36. ECTOPICS : SUPRAVENTRICULAR

37. ECTOPICS:VENTRICULAR

38. E C G: TACHYARRHYTHMIAS

39. E C G:TACHY ARRHYTHMIAS TYPES BASED ON ORIGIN: Supra Ventricular Tachycardia, Ventricular Tachycardia BASED ON MORPHOLOGY: Narrow QRS Tachycardia, Broad QRS Tachycardia BASED ON RHYTHM: Regular Tachycardia , Irregular Tachycardia BASED ON MECHANISM: Reentry, Non Reentry, Pre excitation

40. E C G:TACHY ARRHYTHMIAS

41. E C G:TACHY ARRHYTHMIAS A : AV Nodal Reentry B : AV Reentry C : Atrial Tachycardia

42. E C G: TACHY ARRHYTHMIAS JUNCTIONAL TACHYCARDIA

43. E C G:TACHY ARRHYTHMIAS ATRIAL FIBRILLATION

44. E C G: TACHY ARRHYTHMIAS ATRIAL FLUTTER

45. E C G: TACHY ARRHYTHMIAS MULTIFOCAL ATRIAL TACHYCARDIA

46. E C G:TACHY ARRHYTHMIAS VENTRICULAR TACHYCARDIA NEGATIVE QRS IN V 1 -V 6 AV DISSOCIATION QR COMPLEXES IN V 4 -V 6 LT / NORTH WEST AXIS CAPTURE BEATS NARROW R WITH SLURRED DELAYED S QRS > 0.12s

47. E C G:TACHY ARRHYTHMIAS VENTRICULAR TACHYCARDIA

48. E C G:TACHY ARRHYTHMIAS TORSADES DE POINTES

49. E C G:TACHY ARRHYTHMIAS VENTRICULAR FIBRILLATION

50. E C G: BRADY ARRYHTHMIAS

51. E C G:BRADY ARRYHTHMIAS JUNCTIONAL(A V NODAL) RHYTHM

52. E C G:BRADY ARRHYTHMIAS IDIOVENTRICULAR RHYTHM

53. E C G : OTHER COMMON CHANGES

54. PERICARDITIS

55. PERICARDIAL EFFUSION

56. HYPERTENSIVE HEART DISEASE

57. PULMONARY EMBOLISM

58. E C G:K + ABNORMALITY HYPOKALEMIA HYPERKALEMIA