ECG The Acute Coronary Syndromes

ECG - Acute Coronary Syndromes Reviewing ECG for changes related to ACS ECGs evolve over time, during and after ACO ECG interpretation linked to management decisions Systematic approach to reading ECGs Principles discussed and examples of Macstrak ECG data capture

ACS - early assessment ECG can provide answers to: Acute Coronary Occlusion (ACO) Is the vessel open or closed? How long was it closed? What territory is at risk? Threatened ACO (TACO) Is there a risk of an occlusion event? Consequences of an occlusion event?

ACO - early assessment ECG assessed in conjunction with history at presentation – e.g. prolonged chest pain? Artery open/closed? ST elevation means closed Duration of occlusion: ST resolution artery may have opened Q waves present long duration of closure ST elevation shape convex early occlusion ST elevation shape concave late occlusion

ACO - early assessment Each lead looks at specific area of myocardium Grouped leads represent heart muscle territory Territory Leads Coronary inferior II,III,aVF RCA or Circ anterior V1-V4 LAD lateral I,aVL Diagonal or OM apical V5-V6 LAD posterior V7-V9 Circ Inferior STUp requires a right sided ECG RV V4R RCA

LM RCA Circ LAD

TACO - early assessment TACO (Threatened ACO) arteries have unstable plaque or partial occlusion that is at risk for complete closure Risk of occlusion event is greater if: pain is cardiac; troponins +ve; ST’s, T’s changing pain at presentation or recent prolonged > brief episodes (>2 min) pain present despite therapy (ASA, clopidogrel, heparin, GP2b/3a inhib., IABP)

TACO - early assessment Consequences of occlusion event: What is the territory at risk ? anterior large inferior with RV involvement previous infarction – Q waves Clinical assessment during ischemia hypotension, pulmonary edema

ACS - ECG interpretation Approach: Rhythm: Is it NSR? If not – intervention for brady/tachy? Is morphology valid? P wave - in sync with QRS QRS width > .12 RBBB V1- rSR, V6 - RS LBBB V1- QS, V6 - RR

ACS - ECG interpretation Approach: The ECG can be used to look for ACS changes when none of the following conditions are present: LBBB Paced VT Accelerated idioventricular rhythm (AIVR)

ACS - ECG interpretation Approach: Morphology: ST’s - Up or down - ST Up - 1 mm, except V1-4 2 mm - ST Down 1 mm (flat) Q’s - .04 wide (one box) T’s - inversion (where QRS is positive) V4R - ST Up - 1 mm V7-V9 - ST Up - 1 mm

ECG Case Studies

Patient arrived in the ER with complaint of severe chest pain and diaphoresis. The pain had been present for 30 minutes.

Using the approach presented P wave matches QRS QRS width 0.10 Will morphology be valid? YES

x x x x

Patient presented to a hospital with PCI capabilities and underwent a primary PCI. This is his ECG the next day.

Using the approach presented P wave matches every QRS QRS width 0.08 Will morphology be valid? YES

x x x

These are the pictures from the patient’s PCI These are the pictures from the patient’s PCI. The top picture shows an acute total occlusion of the RCA. The bottom, shows restored blood flow to the area supplied by the RCA.

Patient presented with a history of on and off chest pain yesterday that became continuous and more intense about 3 hours ago.

Using the approach presented P wave one with QRS QRS width 0.12 Will morphology be valid? YES Note: First three beats are ectopic atrial – not NSR but morphology is valid

x x x x

The picture on the left side shows an occlusion of the proximal RCA The picture on the left side shows an occlusion of the proximal RCA. The right side picture shows the open RCA after PCI.

Patient presented with chest pain, diaphoresis, and dizziness Patient presented with chest pain, diaphoresis, and dizziness. Blood pressure was 100/60.

Using the approach presented P wave with every QRS QRS width 0.10 Will morphology be valid? YES

x x x

Since the previous ECG showed an acute inferior MI, the staff completed a 15 lead ECG 2 minutes after the original one. R XX V8 XX V9

Using the approach presented P wave with each QRS, PAC’s XX V8 XX V9 Using the approach presented P wave with each QRS, PAC’s QRS width 0.10 Will morphology be valid? YES

XX V8 XX V9 x x x x x x

Patient presents with waxing and waning chest tightness Patient presents with waxing and waning chest tightness. He has been having mild tightness for 10 minutes. No other symptoms.

Using the approach presented P wave with every QRS QRS width 0.08 Will morphology be valid? YES

x x

Patient was given NTG spray and is currently pain free Patient was given NTG spray and is currently pain free. A repeat ECG is done.

Using the approach presented P wave with every QRS QRS width 0.08 Will morphology be valid? YES

x

Two hours after the initial episode, the patient c/o chest tightness that is a bit more intense. He says its been there for 10 minutes but he thought it would go away so he didn’t bother the nurse.

Using the approach presented P wave with each QRS QRS width 0.10 Will morphology be valid? YES

x x x x

Culprit lesion at ostium of a large intermediate branch, successful PCI

Patient presents 1 day after experiencing chest pain after shovelling snow. He is diaphoretic, short of breath and dizzy. His BP is 95/50.

Using the approach presented P wave with each QRS QRS width 0.12.-0.14 Will morphology be valid? YES - RBBB, V1 mostly +, V6 mostly -, S wave

x x x x x

More examples

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Acute occlusion of proximal LAD, opened with Primary PCI

x

Moving baseline, should repeat ECG x x x

x x x x

Morphology only from narrow beats x x x x x

Note RBBB x