ECG Interpretation Made Easy

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1 ECG Interpretation Made Easy Dr. A Tageldien Abdellah, MSc MD EBSC Lecturer of Cardiology- Hull University Hull York Medical School

2 ECG Interpretation Made Easy Synopsis Benefits Objectives Process Disclaimer

3 Electrocardiogram (ECG)

4 Conductive System of the Heart

5 ECG and Conductive System

6 Electrical Conduction in the Heart Pacemaker Intrinsic Rate SAN bpm AVN bpm His Bundle bpm Purkinje Fibers bpm

7 ECG Waves and Segments

8 ECG Waves and Segments

9 ECG Waves and Segments Bazett's formula: QT corrected = QT measured SQRT (RR interval)

10 12-lead ECG

11 12-lead ECG

12 Normal ECG

13 Where ECG leads look at? Lateral Anterior/ Septal Anterior Inferior Lateral Anterior/ Septal Lateral Inferior Inferior Anterior Lateral

14 ECG Analysis Step 1: Is the Rhythm Regular or Irregular? Step 2: Are All QRS Complexes Similar and Narrow, and is ST segment is isoelectric? Step 3: Are All P Waves Similar and Are PR Intervals Normal? Step 4: Is the Rate Normal? Step 5: Do Waves and Complexes Proceed in Normal Sequence?

15 Systematic ECG Analysis 1. Check the patient details - is the ECG correctly labelled? 2. What is the rate? 3. Is this sinus rhythm? If not, what is going on? 4. What is the mean frontal plane QRS axis? 5. Are the P waves normal (Good places to look are II and V1)? 6. What is the PR interval? 7. Are the QRS complexes normal? 8. Are the ST segments normal, depressed or elevated? 9. Are the T waves normal? 10. What is the QT interval? 11. Are there abnormal U waves?

16 Systematic ECG Analysis: Heart Rate Estimation

17 Systematic ECG Analysis: Cardiac Axis

18 Systematic ECG Analysis: Cardiac Axis Three Easy steps 1- Estimate the overall deflection (positive or negative, and how much) of the QRS in standard lead I. 2- Do the same for avf. 3- Plot the vector on a system of axes, and estimate the angle. Normal QRS axis Normal axis = -30 to +120 degrees Left axis deviation is left of -30 degrees Right axis deviation is right of +120 degrees Axis is abnormal Lead II is more negative than positive. Lead III is more positive than lead II.

19 Systematic ECG Analysis: Cardiac Axis RAD LAD Intermediate Axis RAD LAD Intermediate Axis RAD LAD Intermediate Axis

20 Common ECG Abnormalities I- Abnormalities involving ECG waves and segments. II- Pacemaker Abnormalities. III- Conduction Abnormalities. IV- Ischemic Abnormalities. V- Miscellaneous Abnormalities.

21 I- Abnormalities of ECG Waves and Segments P Wave Abnormalities: left Atrial Enlargement Prolonged P wave duration of 0.12 seconds or more Notched upright P wave duration in leads I, II, V4 to V6 Deep, broad terminal negative deflection in V1 No significant shift in P wave axis Common in Mitral Stenosis and HTN

22 I- Abnormalities of ECG Waves and Segments P Wave Abnormalities: Right Atrial Enlargement Normal P wave duration Tall, peaked P waves with an amplitude greater than 2.5 mm in leads II, III, avf Positive deflection of the P wave in lead V1 or V2 is greater than 1.5 mm Common in Pulmonary Hypertension and COPD

23 I- Abnormalities of ECG Waves and Segments P Wave Abnormalities: Biatrial Enlargement Large biphasic P wave in V1 with initial positive portion of the P wave greater than 1.5 mm and terminal negative component up to 1 mm in depth and 0.04 seconds in duration Tall, peaked P wave greater than 1.5 mm in the right precordial leads (V1, V2) and a wide, notched P wave in the limb leads or leads (V5 and V6). Increase in both amplitude (2.5 mm or more) and duration (0.12 seconds or more) of the P wave in the limb leads.

24 I- Abnormalities of ECG Waves and Segments QRS Abnormalities: Q Wave in Myocardial Infarction Septal Localizing Old Myocardial Infarction by Presence of Q-Wave V1, V2 Inferior MI Anterior Lateral Inferior V1, V2, V3, V4 I, avl, V5, V6 II, III, avf Antero-spetal MI

25 I- Abnormalities of ECG Waves and Segments QRS Changes in Ventricular Hypertrophy

26 I- Abnormalities of ECG Waves and Segments QRS Changes in Ventricular Hypertrophy RVH LVH

27 I- Abnormalities of ECG Waves and Segments T Wave abnormalities T wave abnormalities are common and often rather nonspecific. Ischaemia: T wave is inverted and symmetrical. It is very important to know the features of hypo/hyperkalaemia. Hyperkalaemia Hypokalaemia

28 I- Abnormalities of ECG Waves and Segments T Wave abnormalities in Hyperkaleamia Flattened P wave with 1 st * HB

29 II- Pacemaker Abnormalities

30 II- Pacemaker Abnormalities Supraventricular Abnormalities

31 II- Pacemaker Abnormalities Supraventricular Abnormalities

32 II- Pacemaker Abnormalities Supraventricular Abnormalities

33 II- Pacemaker Abnormalities Supraventricular Abnormalities

34 II- Pacemaker Abnormalities Supraventricular Abnormalities

35 II- Pacemaker Abnormalities Supraventricular Abnormalities

36 II- Pacemaker Abnormalities Supraventricular Tachycardia with Irregular Heart Rate Atrial Fibrillation Atrial Flutter with variable Atrio-Ventricular Block Multifocal (Chaotic) Atrial Tachycardia Multiple Premature Atrial Complexes

37 II- Pacemaker Abnormalities Supraventricular Tachycardia with Irregular Heart Rate *Atrial Fibrillation

38 II- Pacemaker Abnormalities Supraventricular Tachycardia with Irregular Heart Rate *Atrial Fibrillation (slow ventricular response)

39 II- Pacemaker Abnormalities Supraventricular Tachycardia with Irregular Heart Rate *Atrial Fibrillation (fast ventricular response)

40 II- Pacemaker Abnormalities Supraventricular Tachycardia with Irregular Heart Rate *Multifocal (Chaotic) Atrial Tachycardia in one lead

41 II- Pacemaker Abnormalities Supraventricular Tachycardia with Irregular Heart Rate *Multiple Premature Atrial Complexes

42 II- Pacemaker Abnormalities Supraventricular Tachycardia with Irregular Heart Rate Atrial Flutter with variable AtrioVentricular Conduction

43 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate Atrial Flutter with fixed (i.e. 2:1) AtrioVentricular Conduction Atrioventricular-Nodal Reenterant Tachycardia (AVNRT) Atrioventricular Reenterant Tachycardia (AVRT) Atrial Tachycardia (AT)

44 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate *Atrial Flutter with 2:1 AtrioVentricular Conduction

45 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate: *Atrioventricular-Nodal Reenterant Tachycardia (AVNRT) No Clearly Visible P Waves

46 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate: *Atrioventricular Reenterant Tachycardia (AVRT)

47 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate: *Atrial Tachycardia (AT)

48 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate Atrioventricular-Nodal Reenterant Tachycardia (AVNRT) Atrioventricular Reenterant Tachycardia (AVRT) Atrial Tachycardia (AT) P is not seen (and probably lost within the QRS) P is after the QRS, consider accessory pathway P is inscribed before the QRS with abnormal morphology A re-entrant circuit between slow and fast pathways of the AVN A re-entrant circuit via an accessory pathway P wave coming from ectopic atrial focus

49 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate Atrioventricular-Nodal Reenterant Tachycardia (AVNRT) Atrioventricular Reenterant Tachycardia (AVRT) Atrial Tachycardia (AT)

50 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate Atrioventricular-Nodal Reenterant Tachycardia (AVNRT) Atrioventricular Reenterant Tachycardia (AVRT) Atrial Tachycardia (AT)

51 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate Atrioventricular-Nodal Reenterant Tachycardia (AVNRT)

52 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate Atrioventricular-Nodal Reenterant Tachycardia (AVNRT) No Clearly Visible P Waves

53 II- Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate AtrioVentricular Reenterant Tachycardia (AVRT)

54 Pacemaker/Conduction Abnormalities Accessory Pathway or Wolf Parkinson White (WPW) Syndrome Abnormal, congenital extra pathways between the atria and ventricles or/and conduction tissue, and can perforate the electrically insulating fibrous ring that normally separates the atrial and the ventricular chambers. Atrio-Ventricular conduction could be achieved bypassing the AV node. This means that fast Atrial rates (i.e. AF) could be conducted to ventricles at high rates causing serious tachycardia.

55 Pacemaker/Conduction Abnormalities WPW Syndrome The WPW syndrome is a combination of the pre-excitation pattern, and tachycardia. The tachycardia may be due to impulse conduction down via the AV node and back up the accessory pathway (commonest, called orthodromic tachycardia) The other way around (down accessory pathway, up AV node, termed antidromic tachycardia) WPW Syndrome = short PR interval + Delta wave + Wide QRS complex + Tachycardia Pre-exited ECG = short PR interval + Delta wave + Wide QRS complex

56 Pacemaker Abnormalities Supraventricular Tachycardia with Regular Heart Rate AtrioVentricular Reenterant Tachycardia (AVRT)

57 Pacemaker/Conduction Abnormalities Pre Excited ECG

58 II- Pacemaker Abnormalities Ventricular Abnormalities Ventricular Extrasystoles

59 II- Pacemaker Abnormalities Ventricular Abnormalities Nonsustained Ventricular Tachycardia Runs of repetitive premature ventricular impulses (rate > 100/m) lasting < 30s are subgrouped into salvos of 3 to 5 consecutive impulses and nonsustained VT of six or more impulses in duration.

60 II- Pacemaker Abnormalities Ventricular Abnormalities Sustaiend Ventricular Tachycardia Monomorphic Polymorphic Ventricular Tachycardia (Torsaed des Pointes)

61 II- Pacemaker Abnormalities Ventricular Abnormalities Ventricular Fibrillation and Asystole

62 II- Pacemaker Abnormalities Ventricular Abnormalities Ventricular Flutter Ventricular 'flutter' is a bizarre sine-wave like rhythm, and usually degenerates into ventricular fibrillation.

63 II- Pacemaker Abnormalities Ventricular Abnormalities Ventricular Fibrillation and Asystole

64 III- Conduction Abnormalities 1) Sino-Atrial Block 2) Atrio-Ventricular Block 3) Bundle Branch Block 4) WPW Syndrome (mentioned before in Pacemaker Abnormalities) 5) The Long QT Syndrome

65 III- Conduction Abnormalities Sino-Atrial Block

66 III- Conduction Abnormalities Atrio-Ventricular Block

67 III- Conduction Abnormalities Atrio-Ventricular Block First Degree Heart Block

68 III- Conduction Abnormalities Atrio-Ventricular Block Second Degree Heart Block (Mobitz I) or (Wenckebach)

69 III- Conduction Abnormalities Atrio-Ventricular Block Second Degree Heart Block (Mobitz II)

70 III- Conduction Abnormalities Atrio-Ventricular Block Third Degree Heart Block

71 III- Conduction Abnormalities Bundle Branch Block

72 III- Conduction Abnormalities Left Bundle Branch Block

73 III- Conduction Abnormalities Left Bundle Branch Block

74 III- Conduction Abnormalities Right Bundle Branch Block

75 III- Conduction Abnormalities Right Bundle Branch Block

76 III- Conduction Abnormalities Left Anterior Fascicular Block

77 III- Conduction Abnormalities The Long QT Syndrome Normally, the QT-interval is less than 50% of the preceding RR-interval. The long QT-interval symbolises a long ventricular systole. The ST-interval is simultaneous with the phase 2 plateau of the ventricular membrane action potential. The slow Ca2+ -Na+ - channels remain open for more than 300 ms as normally. The net influx of Ca2+ and Na+ is almost balanced by a net outflux of K+. Hereby, a long phase 2 plateau or isoelectric segment is formed. Long QT syndrome one of the common causes of unexplained sudden cardiac death (especially in young people) due to occurrence of fatal arrhythmia called (Torsades de pointes, i.e. polymorphic VT).

78 III- Conduction Abnormalities The Long QT Syndrome

79 III- Conduction Abnormalities The Long QT Syndrome

80 IV- Ischemic Abnormalities

81 IV- Ischemic Abnormalities

82 IV- Ischemic Abnormalities

83 IV- Ischemic Abnormalities

84 IV- Ischemic Abnormalities

85 IV- Ischemic Abnormalities

86 IV- Ischemic Abnormalities

87 IV- Ischemic Abnormalities

88 IV- Ischemic Abnormalities

89 IV- Ischemic Abnormalities

90 IV- Ischemic Abnormalities

91 IV- Ischemic Abnormalities

92 IV- Ischemic Abnormalities

93 IV- Ischemic Abnormalities

94 IV- Ischemic Abnormalities

95 IV- Ischemic Abnormalities

96 IV- Ischemic Abnormalities