ECG interpretation: NSTEMI

Primary PCI and direct admission of high risk NSTEMI

Ron Lilly SASJoanne Simpson GJNH

Wednesday 17th February 2016

Aims

· Recognise the ECG patterns which occur in NSTEMI· Focus on those which occur most commonly· Difficult ECG scenarios

NSTEMI definitionST elevation myocardial infarction (STEMI)

· acute chest pain and persistent ST elevation

· generally reflects an acute total coronary occlusion

· immediate reperfusion by primary angioplasty

Non ST elevation myocardial infarction (NSTEMI)

· acute chest pain with or without ECG changes

· partial occlusion of a coronary artery

Myocardial Infarction

NSTE-ACS

Secondary Prevention/Long-Term ManagementManagement Prior to

NSTE-ACS

Onset of NSTE-ACS-Initial recognition and management in the ED by first responders or ED personnel -Risk stratification-Immediate management

Hospital Management-Medication-Conservative versus invasive strategy-Special groups-Preparation for discharge

Final Dx

Cardiac Biomarker

ECG

Working Dx

Presentation Ischemic Discomfort

ACS

No ST Elevation

NQMI

STEMINSTEMIUA

Unstable AnginaQwMI

ST Elevation

Noncardiac Etiologies

* *

NSTEMI definition

Assessment of a patient with suspected ACS

NSTEMI: considerations

Clinical spectrum

Symptom free

Ongoing ischaemia

Haemodynamic

instability

Cardiac arrest

• Ongoing pain• Marked ST depression• Heart failure• Electrical or haemodynamic

instability

NSTEMI: ECG changes

· persistent or transient ST-segment depression

· T-wave inversion

· flat T waves or pseudo-normalization of T waves

· normal ECG

1. What does this ECG show?

1. What does this ECG show?

1. T wave flattening inferiorly

2. Normal ECG

3. T wave inversion

4. ST depression

ST depression

2. What does this ECG show?

2. What does this ECG show?

1. Normal ECG

2. T wave inversion

3. ST elevation

4. ST depression

3. What does this ECG show?

3. What does this ECG show?

1. Normal ECG

2. T wave inversion

3. ST elevation

4. ST depression

Pre-hospital ECG

Wellen’s syndrome

· T waves: deeply inverted or biphasic

· Critical stenosis of left anterior descending artery

· Patients are high risk

Difficult ECGs

· Mimics are common

· Aim remains not to miss STEMI or high risk NSTEMI

· Low threshold for discussion

1. What does this ECG show?

1. What does this ECG show?

· ST elevation anteriorly

· ST depression

· Left bundle branch block

· Long QT interval

2. What does this ECG show?

2. What does this ECG show?

· Left ventricular hypertrophy

· Anterior ST elevation

· ST depression

· Normal ECG

3. What does this ECG show?

· ST depression

· Anterior ST elevation

· Left ventricular hypertrophy

· Broad QRS complex

3. What does this ECG show?

Electrolyte abnormality

· Potassium, sodium, calcium and magnesium all essential for normal electrical activity of heart

· Characteristic ECG changes but many are non specific

· Consider in:

- underlying kidney disease

- vomiting, diarrhoea and dehydration

Summary

· The clinical presentation is paramount

· ECG changes in combination with positive troponin highly suggestive of NSTEMI

· Be aware of mimics

Extra ECGs if have time

ST depression

ST depression

T wave inversion

Wellen’s syndrome

Wellen’s syndrome

Right bundle branch block