PARA226 Week 1 Lecture Slides PDF

Understanding 12 Lead ECGs for Paramedics Lesson 1 of 3 Introduction to the 12 Lead ECG Marc Colbeck © Paramedicine.com, used by permission of the author. Content licensed under creative commons “share and share alike” license. See: https://creativecommons.org/licenses/by-sa/2.5/au/. Maintaining t...

Understanding 12 Lead ECGs for Paramedics Lesson 1 of 3 Introduction to the 12 Lead ECG Marc Colbeck © Paramedicine.com, used by permission of the author. Content licensed under creative commons “share and share alike” license. See: https://creativecommons.org/licenses/by-sa/2.5/au/. Maintaining this note in the file is sufficient attribution of authorship as per the author. Introduction ECG versus EKG What’s the difference? 2 | Introduction The amazing history of the EKG! “Find out how electrocuting chickens (1775), getting laboratory assistants to put their hands in buckets of saline (1887), taking the ECG of a horse and then observing their open heart surgery (1912), induction of indiscriminate angina attacks (1931), and hypothermic dogs (1953) have helped to improve our understanding of the ECG as a clinical tool. And why is the ECG labelled PQRST (1895)?” http://ecglibrary.com/ecghist.html 3 | Topics 1. 2. 3. 4. 5. 6. 7. 4 | Why do 12 Lead ECGs? Who are ACS suspects? Why take several 12 Leads? How do you acquire a 12 Lead? The new leads Introduction to the 12 Lead layout Pre-analysis Topics 1. 2. 3. 4. 5. 6. 7. 5 | Why do 12 Lead ECGs? Who are ACS suspects? Why take several 12 Leads? How do you acquire a 12 Lead? The new leads Introduction to the 12 Lead layout Pre-analysis Why Do 12 Lead ECGs? To recognize Acute Coronary Syndrome (ACS) The 12L ECG can suggest other conditions as well, such as: • Pulmonary embolism, • Increased ICP, • Pericarditis, • Takotsubo, • Wolf-Parkinson White, • Digoxin effects, • Hyperkalaemia • Etc. 6 | https://i.ytimg.com/vi/zo8Ia6GSi3U/maxresdefault.jpg Why Do 12 Lead ECGs? There is AI assisted interpretation on most 12L machines … 7 | Why Do 12 Lead ECGs? Don’t trust the AI! What is the rhythm? 8 | Why Do 12 Lead ECGs? ACS Also called thrombolytics Fibrinolytics Break up the clot using drugs 9 | Hospital or Paramedics Percutaneous Coronary Intervention PCI Break up the clot using mechanical means Catheter lab in hospital Why Do 12 Lead ECGs? • Improves patient outcomes • Does not significantly delay transport – Takes only one or two minutes to perform. • Gives you an idea of when to call ICP/CCPs • Allows a pre-alert to the hospital for a STEACS patient – Gives the cath lab personnel time to prepare. • Provides the ED with a ‘baseline’ ECG to historical ECGs and to the one performed on ED arrival. 10 | Topics 1. 2. 3. 4. 5. 6. 7. 11 | Why do 12 Lead ECGs? Who are ACS suspects? Why take several 12 Leads? How do you acquire a 12 Lead? The new leads Introduction to the 12 Lead layout Pre-analysis Who Are ACS Suspects? Diagnosis ACS must be evaluated in any patient complaining of ‘nose-to-navel’ pain or discomfort Evaluation Interview 12 | Examination Who Gets a 12 Lead? • Performed during the secondary assessment • Performed at regular intervals if there is a clinical suspicion of ACS • Patients who have an “RSVP3” presentation • Also, be highly suspicious of AMI in: 1. Chest discomfort, shortness of breath, altered mental status. 2. Patients with pre-existing neuropathy (CVA, DM, degenerative neuro diseases) 3. Anyone with a ‘weird’ ECG rhythm strip. 4. Agitated/sympathomimetic patients 5. Any kid with a ‘funky’ heart disease you don’t know! 13 | Topics 1. 2. 3. 4. 5. 6. 7. 14 | Why do 12 Lead ECGs? Who are ACS suspects? Why take several 12 Leads? How do you acquire a 12 Lead? The new leads Introduction to the 12 Lead layout Pre-analysis Why Take Several 12 Leads? Perform repeated ECGs at regular intervals (5-10 minutes) if you clinically suspect ACS. 15 | http://www.londonambulance.nhs.uk/images/patient%20being%20diagnosed%20with%2012-lead%20ecg.jpg Why Take Several 12 Leads? These tracings show how much the ECG can change in a short time. @ 4:06 @ 4:18 16 | Topics 1. 2. 3. 4. 5. 6. 7. 18 | Why do 12 Lead ECGs? Who are ACS suspects? Why take several 12 Leads? How do you acquire a 12 Lead? The new leads Introduction to the 12 Lead layout Pre-analysis The New Leads The machine always looks from the position of the positive, towards the negative. + 19 | The arrow can be confusing. Remember, the arrow goes in your eye! http://4.bp.blogspot.com/_7qy8TydcWaU/TC9SxNrWQ3I/AAAAAAAAAAo/g6k9-yEWwqo/s1600/iStock_000006901811XSmall.jpg The New Leads The first six leads – the vertical plane • I, II, III • aVR, aVL, aVF 20 | The New Leads Review of I, II & III Bipolar l (+/-) “limb leads” 21 | The New Leads Augmented Voltage* Leads • Unipolar leads which calculate the negative lead by taking the average between the two other leads. 22 | * Some sources call these Augmented VECTOR Leads The New Leads Frontal Plane aVR is an “upside down” Lead II aVR aVL I II III The six “Frontal” or “Limb” leads 23 | aVF Einthoven’s Triangle Memorize This! The New Leads The last six leads – the horizontal plane • V1, V2, V3, V4, V5, V6 The six “Horizontal” or “Precordial” leads 24 | Memorize This! The New Leads Horizontal Plane • • • Also unipolar leads Use a calculated negative lead Wilson's central terminal, or “WCT” WCT 25 | The New Leads What parts of the heart CAN’T we see? • • 26 | Right side (the right ventricle) Posterior (back of the left ventricle) The New Leads Right Side V4R fifth intercostal space on RIGHT midclavicular line The right sided leads VR1 – VR6 (V4R is most diagnostic – the rest are not often used) 27 | The New Leads Posterior V7 V8 V9 fifth intercostal space on left posterior axillary line fifth intercostal space on left midscapular line fifth intercostal space on left paraspinal line The three “posterior” leads V7, V8 & V9 28 | The New Leads 29 | Topics 1. 2. 3. 4. 5. 6. 7. 31 | Why do 12 Lead ECGs? Who are ACS suspects? Why take several 12 Leads? How do you acquire a 12 Lead? The new leads Introduction to the 12 Lead layout Pre-analysis Introduction to 12 Lead Layout Paramedic Hospital 32 | Introduction to 12 Lead Layout A rhythm strip 33 | Introduction to 12 Lead Layout The 12 different leads 34 | Introduction to 12 Lead Layout II 35 | I aVR V1 V4 II aVL V2 V5 III aVF V3 V6 Introduction to 12 Lead Layout 10 Seconds of Heart Beat • The machine begins by printing out leads I, II, and III simultaneously. • After 2.5 seconds the machine switches to three new leads, aVR, aVL, aVF. • Two-and-a-half seconds later it prints V1, V2 and V3. • Finally it prints V4, V5 and V6. • The computer analyzes all 10 seconds of all 12-leads although it prints out only 2.5 seconds of each group. 36 | Introduction to 12 Lead Layout I aVR V1 V4 V7 II aVL V2 V5 V8 III aVF V3 V6 V9 Rhythm Strip(s) (II) V4R V4R and V7-V9 are not on the standard printout of a 12 L. 37 | Memorize This! Introduction to 12 Lead Layout • aVR has multiple uses • As novices, we mostly use it to ensure correct electrode placement I aVR V1 V4 II aVL V2 V5 III aVF V3 V6 Rhythm Strip(s) (II) 38 | Introduction to 12 Lead Layout Septal 39 | Anterior Lateral I aVR V1 V4 II aVL V2 V5 III aVF V3 V6 Inferior Septal: V1, V2 Anterior: V3, V4 Lateral high: I, AVL Lateral low: V5, V6 Inferior: II, III, AVF Memorize This! Topics 1. 2. 3. 4. 5. 6. 7. 41 | Why do 12 Lead ECGs? Who are ACS suspects? Why take several 12 Leads? How do you acquire a 12 Lead? The new leads Introduction to the 12 Lead layout Pre-analysis Pre-Analysis 1. 2. 3. 4. 5. 6. Confirm ECG is from your patient Confirm it’s a useful tracing Confirm correct paper Speed Confirm correct voltage Amplitude Confirm correct Frequency response Confirm correct electrode Placement SAFe Placement V4R 42 | Pre-Analysis 1. Confirm ECG is from your patient • Usually not a problem for paramedics • But it can be a problem in hospital! V4R 43 | Pre-Analysis 2. Ensure it’s a useful tracing (1) V4R 44 | Pre-Analysis 2. Ensure it’s a useful tracing (2) • There should be at least one clear P-QRS-T complex visible in every lead V4R 45 | Pre-Analysis 3. Confirm paper speed Time 1mm = 0.04s V4R 46 | Pre-Analysis Paper Speed 47 | V4R Pre-Analysis 4. Confirm voltage amplitude Voltage 1cm (10mm) = 1mV V4R 48 | Pre-Analysis Calibration Amplitude 49 | V4R Pre-Analysis 5. Confirm frequency response V4R 3-Lead ECG “Monitor” Quality = 1 Hz to 30 Hz 50 | Pre-Analysis 5. Confirm frequency response V4R 12-Lead ECG “Diagnostic” Quality = 0.05 Hz to 150 Hz 51 | Pre-Analysis Frequency Response 52 | V4R Pre-Analysis 5.“Frequency Response” Monitor Quality 1-30Hz ‘Field’ Quality 0.05-40Hz Rhythm Interpretation Only Field 12 Lead ECGs Do NOT use for 12 lead interpretation Some ‘field’ monitors are now diagnostic. Diagnostic Quality 0.05-150Hz In-hospital 12 Lead ECGs Too sensitive for us V4R Pre-Analysis “Monitor Quality” = 1-30 Hz 54 | V4R Pre-Analysis “Diagnostic Quality” = 0.05-150Hz 55 | V4R Pre-Analysis 5.“Frequency Response” • Always use “DIAGNOSTIC QUALITY” to analyze the ECG for signs of AMI. • Use the printed ECG, (not the screen) V4R 56 | Pre-Analysis 6. Confirm electrode placement • Reversal of LA and RA is most common • This results in an upright aVR and downward lead I. • Lead I and V6 will have QRS complexes in opposite directions (they are normally the same) 57 | V4R Pre-Analysis 6. Confirm electrode placement: LARA V4R 58 | Pre-Analysis 6. Confirm electrode placement: RALL • If RA and LL are reversed all the limb leads will look upside down (including aVR, which becomes +) V4R 59 | Pre-Analysis 6. Confirm electrode placement: RL/Limb lead • If RL is switched with any of the limb leads, the tracing will be isoelectric (in that lead) using a 150 Hz frequency response monitor. • RL and III reversal • RL and II reversal 60 | V4R Pre-Analysis 6. Confirm electrode placement: V1 and V2 • The V1 and V2 dots are persistently and consistently (>50% in one study*) placed too high on the chest When this happens, you can get false positives for ACS. MAKE SURE you place V1 and V2 properly! • • 61 | V4R *Wenger W, Kligfield P. Variability of precordial electrode placement during routine electrocardiography. J Electro- cardiol. 1996;29(3):179Y184. Pre-Analysis 6. Confirm electrode placement: V1 and V2 • If you see a negative P wave in V2, • If you see an rSR pattern (not V1), check your placement. in V1 and/or V2, check your placement. R P r S T 62 | rSR means there’s “really Something Rong” with V1 & V2! Pre-Analysis 6. Confirm electrode placement: R wave progression • If the V leads are properly placed (on a normal heart) then there will be a transition from a smaller R wave and a larger S wave in V1 … to a larger R wave and a smaller S wave in V6. V4R 63 | Pre-Analysis 6. Confirm electrode placement: R wave progression • If any of the V leads are misplaced there won’t be proper R wave progression (it will appear out of order). There are other causes of poor R wave progression, but an “outof-order” progression suggests displacement • V4R 64 | Pre-Analysis Normal “R Wave Progression” 1 mm 11 mm 4 mm 10 mm 7 mm 8 mm • This is almost perfect R wave progression – the waves grow and reduce in size in the proper pattern. • The only variation in this ECG is that V4 is slightly larger than V5. • Normally V5 is the largest R wave, (but this is close enough). V4R 65 | https://emergencymedicinecases.com/wp-content/uploads/2020/12/ECGcasesLateR-lead2-768x326.png.webp Pre-Analysis Poor “R Wave Progression” 66 | 1 mm 15 mm 6 mm 13 mm <1 mm 13 mm • V3’s R wave height does not follow our expected pattern • it’s much lower than V2 and V4 • Again, V4 is slightly larger than V5, but that’s an ok variation • This is an example of a misplaced V3 dot https://emergencymedicinecases.com/wp-content/uploads/2020/12/ECGcasesLateR-lead1-768x384.jpg.we Pre-Analysis 6. Confirm electrode placement K.I.S.S. You don’t have to memorize all the presentations of the possible errors in placement, but you should recognize when it’s ‘wrong’. 1. 2. 3. 4. 5. 67 | No leads shouldn’t be isoelectric aVR should be mostly negative (P, QRS and T) I and V6 should both be mostly positive, (or at least in the same direction). There should be no rSR in V1 or V2, or a negative P wave in V2 V4R There should be no ‘out-of-order’ R waves (normal R wave progression) Summary of Pre-Analysis 68 | Memorize This! Pre-Analysis Good tracing (readable) Correct paper speed (25 mm/second) Correct voltage amplitude (1mV=10mm, also note the “x1.0”) Paramedic frequency response (0.05-40 Hz instead of 0.05-150 Hz) Correct electrode placement ✓ aVR is negative and I is positive, I and V6 are both positive ✓ No limb leads are isoelectric or upside down ✓ The P wave in V2 is positive, there’s no rSR in V1-2, but there is poor(ish) R wave progression. V4R 70 | Pre-Analysis Bad tracing (unreadable) Correct paper speed (25 mm/second) Correct voltage amplitude (1mV=10mm, also note the “x1.0”) Paramedic frequency response (0.05-40 Hz instead of 0.05-150 Hz) Correct electrode placement ✓ aVR is negative and I is positive, I and V6 are both positive ✓ No limb leads are isoelectric or upside down ✓ There’s no rSR in V1-2, and the P in V2 is positive BUT there is poor R wave progression V4R 71 | Pre-Analysis Good 12 Lead (suitable for interpretation) 72 | Pre-Analysis 1. 2. 3. 4. 5. 6. • Frequency response is off • Amplitude is twice normal (x2.0) • Don’t interpret this ECG – get a proper one 73 | Confirm ECG is from your patient Confirm it’s a useful tracing (it’s readable) Confirm correct paper Speed (25 mm/second) Confirm correct voltage Amplitude (1mV=10mm) Confirm correct Frequency response (0.05-150 Hz) Confirm correct electrode placement ✓ aVR is negative and I is positive, ✓ I and V6 are both positive ✓ No limb leads are isoelectric or upside down ✓ No rSR in V1-2, ✓ P in V2 is positive, ✓ there is normal R wave progression V4R Pre-Analysis 1. 2. 3. 4. 5. 6. • Much info missing • RA LA reversal (+aVR and I≠V6) • Not a useable ECG – get a better one 74 | Confirm ECG is from your patient Confirm it’s a useful tracing (it’s readable) Confirm correct paper Speed (25 mm/second) Confirm correct voltage Amplitude (1mV=10mm) Confirm correct Frequency response (0.05-150 Hz) Confirm correct electrode placement ✓ aVR is negative and I is positive, ✓ I and V6 are both positive ✓ No limb leads are isoelectric or upside down ✓ No rSR in V1-2, ✓ P in V2 is positive, ✓ there is normal R wave progression V4R Pre-Analysis 1. 2. 3. 4. 5. 6. • Much info missing • RA LL reversal (inverted I, II, III, aVR, aVL, aVF) • Not a useable ECG – get a better one 75 | Confirm ECG is from your patient Confirm it’s a useful tracing (it’s readable) Confirm correct paper Speed (25 mm/second) Confirm correct voltage Amplitude (1mV=10mm) Confirm correct Frequency response (0.05-150 Hz) Confirm correct electrode placement ✓ aVR is negative and I is positive, ✓ I and V6 are both positive ✓ No limb leads are isoelectric or upside down ✓ No rSR in V1-2, ✓ P in V2 is positive, ✓ there is normal R wave progression V4R Summary of Pre-Analysis 76 | Memorize This! After Your Pre-Analysis – interpret the rhythm 77 | Topics 1. 2. 3. 4. 5. 6. 7. 78 | Why do 12 Lead ECGs? Who are ACS suspects? Why take several 12 Leads? How do you acquire a 12 Lead? The new leads Introduction to the 12 Lead layout Pre-analysis Questions 79 |