Acute chest pain and ST Elevation. CT done to look for aortic dissection.....

Written by Willy Frick

A 67 year old man with a history of hypertension presented with three days of chest pain radiating to his back. He had associated nausea, vomiting, and dyspnea.

What do you think?

This ECG together with these symptoms is certainly concerning for OMI, but the ECG is not fully diagnostic, and another consideration could be acute pericarditis. Mistaking OMI for pericarditis is a much more harmful error than the converse. Still, in the interest of studying the ECG, here are some findings that could support pericarditis:

• Absence of large T-waves (flat ST segments)

• Absence of any STD in aVL (which is seen in 99% of inferior OMIs).

• There is no reciprocal depression anywhere (except aVR and V1, the rightward facing leads).

• STE spanning from lead I (0°) all the way to lead III (120°), i.e. diffuse.

• There is appreciable PR depression in a few leads (I, II, V4-6).

• There is Spodick's sign (downsloping TP segment) in a few leads (V3, V4).

• The STE has a more concave morphology (vs the more ischemic coved appearance).

• Ongoing pain despite terminal TWI in a few leads (II, aVF, V5, V6). If this were OMI, that should indicate reperfusion and improving pain.

• There is end QRS slurring in II, aVF, V6 (vs the more ischemic checkmark sign).

• The STE in II is greater than the STE in III.

• The rate is tachycardic, which is uncommon in OMI and common in pericarditis.

There is also low voltage across the ECG.

Important note: None of these findings proves pericarditis. All of them can be seen in OMI. But seeing them all together is more suggestive that pericarditis could be possible.

Due to the chest pain radiating into the patient's back, the ER physician ordered CTA chest to rule out aortic dissection. While awaiting the results of the CT, the physician called cardiology. The cardiologist agreed that the ECG was suggestive of STEMI, but the facility's cath lab was apparently not available and he therefore recommended emergent transfer to a cath capable facility.

A representative still from the CT scan is shown below:

This shows a very large pericardial effusion, which fits with the diagnosis of pericarditis. Recall that pericarditis is diagnosed clinically by any 2 of the following:

• Characteristic pain (pleuritic, worse with deep inspiration and supination)
• Friction rub
• New widespread ST elevation
• New or worsening pericardial effusion

This patient now has at least two of the above (effusion plus STE), making the diagnosis of pericarditis quite likely. This would have been fairly easy and much more expedient to diagnose with bedside echocardiogram. The constellation of dyspnea, tachycardia, and (relatively) low voltage on ECG should prompt immediate evaluation for pericardial effusion and tamponade.

After transfer to a cath capable facility, and before he was taken to lab, repeat ECG was performed and is shown:

Over just an hour or so, the Queen's certainty has improved significantly, and she now has mid confidence that this is not OMI. The patient underwent pericardiocentesis with drainage of 1500 mL of serous fluid! No further ECGs were obtained. Troponin I was serially undetectable.

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This is Version 1 of the Queen of Hearts, which was not trained on pericarditis.  Version 2, coming soon, was trained on many pericarditis ECGs and version 3 on even more.

The Queen of Hearts PM Cardio App is now available in the European Union (CE approved) the App Store and on Google Play.  For Americans, you need to wait for the FDA.  But in the meantime:

YOU HAVE THE OPPORTUNITY TO GET EARLY ACCESS TO THE PM Cardio AI BOT!!  (THE PM CARDIO OMI AI APP)

If you want this bot to help you make the early diagnosis of OMI and save your patient and his/her myocardium, you can sign up to get an early beta version of the bot here.  It is not yet available, but this is your way to get on the list.

https://share-eu1.hsforms.com/18cAH0ZK0RoiVG3RjC5dYdwfyfsg

Learning Points:

• Calling OMI pericarditis is much more harmful mistake than the converse

• Bedside echo demonstrating pericardial effusion can strongly support a diagnosis of pericarditis (and is seen in 60% of cases of acute pericarditis)

• Pericarditis can only be ruled in after proving
• Absence of reciprocal changes (other than V1 and aVR), particularly aVL
• Absence of STE III > II
• Absence of checkmark sign
• Presence of PR depression
• Presence of Spodick's sign

• When you see dyspnea, tachycardia, and lowish voltage, rule out pericardial effusion and tamponade with bedside echocardiogram