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
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
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
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
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.
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