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04-10-2023-Y3-ClineachingCE-T CODE-BLUE-OSCE ECG interpretation Jasmine Spinks ®In Partnership with Enrolled activity under the International Federation of Medical Students’Association (IFMSA) T eaching Medical Skills programme. In Partnership with Comprehensive, accessible OSCE resources, notes, videos and OSCE stations for practice. Use CODEBLUE23 at checkout on GeekyMedics.com for 20% their paid resources **not an affiliate code** Disclaimer • Code Blue OSCE Crew is a platform created by Manchester medical students, independently of the University of Manchester and Manchester Students’ Union • This teaching should not replace any formal teaching provided by the university - Any changes to CCAs would be communicated by your university, follow their guidance • Content is generated by students with input from senior doctors Session Structure 4 2 1 3 How to Group interpret and practice ECG Physiology and Common ECG anatomy of Breakout rooms ECGs abnormalities for 1 hour of OSCE practiceLearning Objectives ✔ Understand the basic physiology behind an ECG ✔ Understand and apply the criteria to determine sinus rhythm ✔ Recall and apply the structure of ECG interpretation in an OSCE setting ✔ Identify common ECG abnormalitiesQuick Quiz! Question 1 A 72 year old male presents to the local emergency department following a fall with a long lie. As part of his initial assessment an ECG is performed on the patient. The ECG is shown below: What electrolyte abnormality is most likely responsible? A. Hyperkalaemia B. Hypokalaemia C. Hypercalcaemia D. Hypocalcaemia E. Hypernatremia Question 2 A 35 year old man presents with palpitations. He has been drinking heavily with friends over the weekend. This is his ECG. Present your findings and give a diagnosis A. Supraventricular tachycardia B. Atrial flutter C. Atrial fibrillation D. Ventricular fibrillation E. Sinus tachycardia Question 3 A fit and well 31 year old man presents for a routine insurance medical. This is his ECG. Present your findings and give the diagnosis. A. Anterior STEMI B. Atrial ectopic C. Sinus tachycardia D. Sinus bradycardia E. Normal sinus rhythmWhat is an ECG? ECG – Electrocardiogram – Electrical trace of the heart Indications: ❑ Chest pain ❑ Syncope ❑ Palpitations ❑ Unexplained fall ❑ Seizures ❑ Electrolyte disturbancesElectrical conduction What are the specialised conducting cells, and what is the pathway? Sinoatrial node (pacemaker) ↓ Internodal pathway ↓ Atrioventricular node ↓ Bundle of his ↓ Right and left bundle branches ↓ Purkinje fibresWhere are the leads?Where are the leads? ECG shows a POSITIVE deflection when the electrical impulse is traveling TOWARDS the positive electrode. It shows a NEGATIVE deflection when the impulse is travelling AWAY from the positive electrodeWhere are the leads? A wave of repolarization travelling towards a positive electrode = Positive deflection Wave of repolarization travelling away from a positive electrode = Negative deflection Wave of depolarization or repolarization travelling perpendicular to an electrode axis = no net deflectionWhere are the leads? Unipolar = registered activity in the heart which is directed towards the electrode aVL, aVR, aVF Bipolar – register the voltage between the two electrodes I, II, III Chest Leads Where are the chest electrodes placed? th V1 = 4 intercostal space to right of sterthm  V2 – 4 intercostal space to left of sternum  V3 – in between leads 2-4 V4- 5 intercostal space midclavicular line  V5 – same level as v4 at left ant. Axillary line  V6- level with V5 at midaxillary line  Cardiac Axis The overall direction of the cardiac impulse of wave of depolarisation Normal:  QRS axis between -30° and +90° Left Axis Deviation: QRS axis less than -30°. Right Axis Deviation: QRS axis greater than +90° LAD: lead I most +ve. Leads II,III negative  RAD: Lead III most +ve. Lead I negative ECG measurements Standardized: • Paper speed: 25mm/s • Gain/amplitude: 10mm/mv • Filters must be set to 0.05Hz-150Hz • Each small square represents 0.04 seconds • Each large square represents 0.2 seconds • 5 large squares = 1 second • 300 large squares = 1 minute HR calculation: 300 large squares is equal to 1 minute at a paper speed of 25mm/sec 300/number of large squares between R-R intervals = BPMWhat is this HR? 300/4 75bpmReading the ECGReading the ECGSinus Rhythm Default rhythm: Regular narrow complex heart rhythm 60-100bpm • Cardiac impulse originates from the sinus node -> every QRS must be preceded by a P wave • P wave should be positive in lead II and negative in aVR + under 2.5mm high • PR = 0.12-0.20 seconds OSCE style interpretation Systematic Approach 1. Confirm patient’s details and calibration – previous ECG strips to compare? 2. Rate, Rhythm and axis – calculate HR, is it regular? Is the axis normal? 3. P waves – present? Followed by a QRS? Normal morphology? 4. PR interval – prolonged/shortened? 5. QRS complex – broad/narrow? Abnormal Q waves? 6. ST segment – elevated/depressed? 7. T wave – normal? Upright T-waves? 8. Anything else? 9. Summarizing to examiner 1.Classifying abnormalities Arrhythmias can be split into Bradycardias and tachycardias: Bradycardias: Node disease and Heart blocks T achyarrhythmias: Supraventricular tachycardia and ventricular tachycardia 1. Atrial Fibrillation and Flutter Both narrow complex (QRS<0.12) Atrial fibrillation: Fast                                                                   and irregular atrial activity. Absent p wave   Irregularly irregular  Atrial flutter:  Fast regular atrial activity (usually 300BPM) Absent p waves – flutter waves  Saw tooth appearance  Presents with block ( 2:1, 3:1…)  Or with variable block  1. SVT •Narrow complex – QRS under 3 small squares •Regular heart rate (120-250) •Normal p-wave  (can be hidden in T wave)  •Originates in atria with rapid ventricular conduction 1. Atrioventricular block 1 degree: slow conduction through AV node Normal QRS, normal P wave  Prolonged P-R interval (over 200ms)  Normal in athletes 2nd degree – 2 types  Mobitz type 1: PR interval prolongation Until P wave is not followed by QRS Pattern repeats  Mobitz type 2: intermittent non-conducted  P waves without progressive prolongation of the PR interval. PR constant  rd 3 degree: AV dissociation  No coloration between P wave/QRS complex  QRS > 3 small squares 1.Atrioventricular block Bundle Branch Block Blocked bundle branches lead to delayed myocardial conduction -> Prolonged QRS Key features  RBBB:  • Broad QRS (>3small square/0.12sec) and • RSR (2 peaks M shaped) pattern in V1 • Slurred S wave in lateral leads I, V5, V6 LBBB: Broad QRS (>3small square/0.12sec) and • Deep S wave in V1 and • No Q wave in V5/V6 1.Bundle Branch Block V entricular T achycardia Usually regular – Board QRS > 3 small squareste of > 130 BPM 2 main types:  Regular, broad complex tachycardia Uniform QRS complexes within each lead Polymorphic: Foci in multiple areas: shape changes from beat to beat Torsades de pointes Pericarditis •Widespread concave ST elevation and PR depression throughout most of the limb leads (I, II, III, aVL, aVF) and precordial leads (V2-6) •Reciprocal ST depression and PR elevation in lead aVR (± V1) •Sinus tachycardia is also common in acute pericarditis due to pain and/or pericardial effusion 1. Hyperkalaemia •Tall tented T waves are >5 mm in the limb leads, and usually >10 mm in the precordial leads •ECG may show: bradycardia, absent p waves and  wide QRS. 1. Coronary artery disease Important ECG changes in ACS New LBBB: •Broad QRS (>3small square/0.12sec) and •Deep S wave in V1 and •No Q wave in V5/V6 Pathological Q- waves: •> 40 ms (1 mm) wide •> 2 mm deep •> 25% of depth of QRS complex •Seen in leads V1-3 STEMI + NSTEMI •Elevation or depression of ST segment (isoelectric line) •Reciprocal ST elevation/depression in opposite leads  •ST segment should not be greater than 1mm above (ST elevation) or below (ST depression) the isoelectric (base) line or 2mm in V1 & V2   NSTEMI also includes:  T wave abnormalities:  inverted T wave (1mm deep)  Coronary artery diseaseAnterior STEMI Left ventricular Hypertrophy •Sokolov-Lyon criteria: S wave depth in V1 + tallest R wave height in V5-V6 > 35 mm 1. Ectopic beats Atrial: premature different shape of p wave followed by normal QRS Junctional: hidden p wave normal QRS  Ventricular: no p wave, early QRS complex -> compensatory pause Arrest rhythms VF: IRREGULAR rapid chaotic waveforms. No recognisable P,QRS T waves  Asystole: no cardiac activity – isoelectric line  P wave asystole : only atrial activity (p waves present no QRS) OSCE Tips from an OSCE Expert Slide for doctor/s - leave this blankDid you learn something new? Question 1 A 72 year old male presents to the local emergency department following a fall with a long lie. As part of his initial assessment an ECG is performed on the patient. The ECG is shown below: What electrolyte abnormality is most likely responsible? A. Hyperkalaemia B. Hypokalaemia C. Hypercalcaemia D. Hypocalcaemia E. Hypernatremia Question 1 A 72 year old male presents to the local emergency department following a fall with a long lie. As part of his initial assessment an ECG is performed on the patient. The ECG is shown below: What electrolyte abnormality is most likely responsible? A. Hyperkalaemia B. Hypokalaemia C. Hypercalcaemia D. Hypocalcaemia E. Hypernatremia Question 2 A 35 year old man presents with palpitations. He has been drinking heavily with friends over the weekend. This is his ECG. Present your findings and give a diagnosis A. Supraventricular tachycardia B. Atrial flutter C. Atrial fibrillation D. Ventricular fibrillation E. Sinus tachycardia Question 2 A 35 year old man presents with palpitations. He has been drinking heavily with friends over the weekend. This is his ECG. Present your findings and give a diagnosis A. Supraventricular tachycardia B. Atrial flutter C. Atrial fibrillation D. Ventricular fibrillation E. Sinus tachycardia Question 3 A fit and well 31 year old man presents for a routine insurance medical. This is his ECG. Present your findings and give the diagnosis. A. Anterior STEMI B. Atrial ectopic C. Sinus tachycardia D. Sinus bradycardia E. Normal sinus rhythm Question 3 A fit and well 31 year old man presents for a routine insurance medical. This is his ECG. Present your findings and give the diagnosis. A. Anterior STEMI B. Atrial ectopic C. Sinus tachycardia D. Sinus bradycardia E. Normal sinus rhythmResources used/recommended Life in the fast lane 0 to finals Geeky medics Ninja nerdGive us feedback to get the slides linktr.ee/codeblueteaching cbosceteaching@gmail.com SPACE FOR QR CODE IG: @codeblueteaching facebook.com/cbosceteaching Now for OSCE practice!