STEMI mimics

Question 1

What are some STEMI mimics?

Answer 1

• Benign Early Repolarisation (BER)
• Pericarditis

Question 2

What is Benign Early Repolarisation?

Answer 2

• not exactly understood

• suspected to be due to an imbalance in the Ion channel system, which results in variable REFRACTORINESS of multiple myocardial regions —> which leads to variable excitability of the Myocardium.

• This leads to specific ECG findings, which can unfortunately mimic STEMI’S

• while this is referred to as benign , this only refers to it not being indicative of Myocardial Ischaemia/Infarction

Question 3

What can Benign Early Repolarisation indicate if seen in INFERIOR or INFERO-LATERAL leads?

Answer 3

It can indicate the patient is at higher risk of IDIOPATHIC VF and Sudden Cardiac Death (SCD)

Question 4

How common is Benign Early Repolarisation (BER)

Answer 4

• Found in 5-15% of individuals
• studies have found that it is present in 10-15% of patients presenting with chest pain to an ED
• BER is more common in younger people <50 years old.

BER SHOULD NOT BE SUSPECTED IN PT’s > 50 .

Question 5

What is BER often referred to as?

Answer 5

High take off

Question 6

ECG features of benign Early Repolarisation BER?

Answer 6

1) widespread concave ST elevation , most prominent in the mid-to-left pre cordial leads (V2-V5).

2) Notching or slurring at the J-point.

3) Prominent, slightly asymmetrical T waves that are Concordant with the QRS complex.

4) NO reciprocal ST depression to suggest Occlusion MI

Question 7

What does concave ST segment elevation look like?

Answer 7

Bit like a smile on a smiley face —> think Smiley face

Question 8

What does J-point notching look like?

Answer 8

Like a small triangle at the end of the QRS , described as a fish hook pattern

Small triangle after S wave , before T wave.

Question 9

BER - what to do is suspected?

Answer 9

1) in PT’s > 50 YO , ACS must be ruled out before BER can be diagnosed, this is because STE in people > 50YO is more likely to be ACS.

• if the PT is <50YO but has clinical signs or symptoms, or a history suggestive of arrythmia , PT will need conveyance to ED , or referral to GP.
• in PT’s <50YO , with no other symptoms suggestive of an arrhythmia , then PT does not need referral for ECG changes alone.

Question 10

What is Pericarditis?

Answer 10

• Inflammation of the Pericardium, usually due to infection.
• when compared to ACS, there are similarities and differences in signs, symptoms and clinical presentation.
• Pericarditis is usually not serious, ACS is.

Question 11

Pericarditis ECG features?

Answer 11

1) Widespread concave ST elevation,

and PR depression throughout most of the limb leads (I , II , III , aVL and aVF) <— all limb leads except aVR . And precordial leads V2-V6.

2) Reciprocal ST depression and PR elevation in aVR (sometimes in V1)

3) sinus tachycardia is also common in acute Pericarditis due to pain/and or Pericardial Effusion.

Question 12

How to differentiate BER v Pericarditis ?

Answer 12

1) ST elevation= in pericarditis it is generalised

In BER it is limited to precordial leads

2) PR depression = in pericarditis —> YES

in BER —> NO

3) T WAVE AMPLITUDE = in Pericarditis —> Normal

IN BER T wave is prominent

4) ST segment/ T wave ratio = in Pericarditis —> > 0.25% ratio

In BER < 0.25% ratio (ONLY APPLICABLE TO V6)

5) Fish hook appearance = in Pericarditis —> NO

in BER —> YES