ECG interpretation in NSTEMI

ECG interpretation: STEMI

Primary PCI and direct admission of high risk NSTEMI

Joanne Simpson Golden Jubilee National HospitalWednesday 17th February 2016

Aims

· Revise the ECG patterns which occur in STEMI· Focus on those which are more difficult to

recognise, but not uncommon · Remember:

Some ECG patterns are not clear cut

Minimising missed STEMIs is the priority

1. What does this ECG show?


· Anterior ST depression

· Left ventricular hypertrophy

· Bundle branch block

· Inferior STEMI


· Inferior T wave inversion

· Lateral T wave inversion

· Inferolateral T wave inversion

· High lateral STEMI


· Left bundle branch block

· Anterior T wave inversion

· Posterior STEMI

· Atrial fibrillation


· Left bundle branch block

· Left ventricular hypertrophy

· Anterior STEMI

· Atrial fibrillation

STEMI

· ST elevation myocardial infarction (STEMI)

Complete (or near complete) occlusion of a coronary artery

→ restriction of blood supply to heart muscle beyond

· This produces characteristic symptoms and ECG changes which allow:

rapid recognition of STEMI

prompt delivery of optimal reperfusion therapy

→ minimise infarct size, risk of future events, early and late mortality

Clinical presentation

Different ECG patterns in STEMI

1. ST elevation reflecting occlusion of a coronary artery

2. Posterior infarct

3. Left bundle branch block


- ‘injury current’ between normal and necrotic Tissue

- occurs in regional patterns




ST elevation due to coronary occlusion

ECG leads over the territory of the occluded artery will show ST

elevation as the injury current travels toward them

ST elevation correlates to the territory of the occluded artery:

Inferior = RCA / LCx

Posterior = RCA / LCx

Lateral = LCx

Anteroseptal = LAD

Circumflex artery (LCx)

Left anterior descending artery (LAD)

Right coronary artery (RCA)

How do ECG leads look at the heart?


Chest leadsFrontal leads

Inferior leads

Anterior leads Lateral leads


Correlating ECG leads with vessel territory

Inferior Lateral

AnteriorInferior leads

Anterior leads Lateral leads


ST elevation in anterior leads

‘Reciprocal’ ST depression in inferior leads

ST elevation in inferior leads

Reciprocal ST depression in anterior leads



ST elevation in high lateral leads

‘Reciprocal’ ST depression in inferior leads



- ‘injury current’ between normal and necrotic tissue



- location means ST elevation is not seen


Posterior wall infarction

Posterior infarct may be caused by RCA or LCx occlusion

- often associated with inferior or lateral ST elevation

Circumflex artery (LCx)

Left anterior descending artery (LAD)

Right coronary artery (RCA)


· No ECG leads ‘look’ directly at the posterior wall of the heart

· Anterior leads are directly opposite and will see the opposite of any current generated at the posterior wall

· posterior ST elevation= anterior ST depression


ST depression in anterior leads

Subtle ST elevation in inferior leads



- ‘injury current’ between normal and necrotic tissue



- location means ST elevation is not seen

3. Left bundle branch block (LBBB)

- if NEW can indicate infarction

- if OLD can obscure ST elevation during an infarct

Left bundle branch block

Left bundle branch block

QRS duration > 3 small squares

Negative QRS across anterior leads with poor R wave progression

Notched R wave in V6

V1

V6

Summary

· The clinical presentation is paramount

· Check each ECG territory in turn for ST elevation

· Look for ST depression

- is this reciprocal change?

- if anterior, could it be a posterior infarct?

· Check the QRS duration

- if > 3 small squares, is there LBBB?

ECG interpretation in NSTEMI

Healthcare

Transcript of ECG interpretation in NSTEMI