Macstrak Project

ECGThe Acute Coronary

Syndromes

Macstrak Project

• 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

ECG - Acute Coronary Syndromes

Macstrak Project

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?

ACS - early assessment

Macstrak Project

• 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

Macstrak Project

• Each lead looks at specific area of myocardium• Grouped leads represent heart muscle territory

Territory LeadsCoronary

inferior II,III,aVF RCA or Circanterior V1-V4 LADlateral I,aVL Diagonal or

OM apical V5-V6

LADposterior V7-V9 Circ

• Inferior STUp requires a right sided ECG

RV V4R RCA

ACO - early assessment

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RCA

LAD

Circ

LM

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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

Macstrak Project

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

TACO - early assessment

Macstrak Project

Approach: Rhythm:1. Is it NSR? If not – intervention for

brady/tachy?2. 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

Macstrak Project

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

Macstrak Project

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

ACS - ECG interpretation

Macstrak Project

ECG Case Studies

Macstrak Project

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

Macstrak Project

Using the approach presentedP wave matches QRSQRS width 0.10

Will morphology be valid? YES

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

Macstrak Project

Using the approach presentedP wave matches every QRSQRS width 0.08

Will morphology be valid? YES

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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.

Macstrak Project

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

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Using the approach presentedP wave one with QRSQRS width 0.12

Will morphology be valid? YES Note: First three beats are ectopic atrial –

not NSR but morphology is valid

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

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

Macstrak Project

Using the approach presentedP wave with every QRSQRS width 0.10

Will morphology be valid? YES

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R

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XX V9

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

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XX V9

Using the approach presentedP wave with each QRS, PAC’sQRS width 0.10

Will morphology be valid? YES

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

Macstrak Project

Using the approach presentedP wave with every QRSQRS width 0.08

Will morphology be valid? YES

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

Macstrak Project

Using the approach presentedP wave with every QRSQRS width 0.08

Will morphology be valid? YES

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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.

Macstrak Project

Using the approach presentedP wave with each QRSQRS width 0.10

Will morphology be valid? YES

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Culprit lesion at ostium of a large intermediate branch, successful

PCI

Macstrak Project

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

Macstrak Project

Using the approach presentedP wave with each QRSQRS width 0.12.-0.14

Will morphology be valid? YES - RBBB, V1 mostly +, V6 mostly -, S wave

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More examples

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Acute occlusion of proximal LAD, opened with Primary PCI

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Moving baseline, should repeat ECG

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Morphology only from narrow beats

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Note RBBB