Hereâ€™s the conclusion toÂ 39 year old male CC: â€œSickâ€
Letâ€™s take another look at the 12-lead ECG.
Several findings in this case point toward pericarditis.
In the first place, the patient is feeling unwell and has a temperature of 100.2 F, the chest pain is â€œsharpâ€ in quality and is reproducible with deep inspiration so itâ€™s atypical for coronary ischemia.
Secondly, the constellation of ST-elevation (or at least J-point elevation) is unusual. For example, you can see J-point elevation in lead I and also leads II and aVF which are reciprocal leads.
Itâ€™s not impossible for a STEMI to have ST-elevation in leads I and II (seeÂ this caseÂ from Dr. Smithâ€™s ECG Blog) but you will notice that the computer incorrectly reads the ECG as pericarditis!
Here are the last few tips to help you identify pericarditis. In the above image which shows a single cardiac cycle in lead II, you can see (A.) PR-segment depression, (B.) a â€œnotchedâ€ J-point, and (C.) upwardly concave ST-segment elevation (if in fact the ST-segment is really elevated in comparison to the TP segment).
An easy way to remember the difference between â€œupwardly concaveâ€ and â€œupwardly convexâ€ (or non-concave in the case of a straight ST-segment which is also bad) is that and â€œupwardly concaveâ€ ST-segment looks like a smiley face (good) and â€œupwardly convexâ€ looks like a frowny face (bad).
Itâ€™s important to remember that acute STEMI can, and often does, present with upwardly concave ST-segments, so the mere fact that the ST-segments are upwardly concave does not mean itâ€™s not a STEMI.
Itâ€™s one piece of the puzzle.
So what happened to the patient? Hereâ€™s what Matt from Mass had to say.
â€œFollow-up with the ER nurse a week later revealed a diagnosis of pericarditis with an unremarkable clinical course after intravenous antibiotics. Etiology of the infection was not determined.
In addition, patient was referred for outpatient cardiologist evaluation for possible Wolff-Parkinson-White syndrome.â€
One of the really cool things about Web 2.0 and social media is â€œpeer sourcingâ€. Since I too thought that lead V3 looked very suspicious (meaning that it looks like a delta wave is present even though the PR interval is not short) I forwarded the ECG to Mark P. from theÂ Electrophysiology FellowÂ blog.
He sometimes leaves comments on my case studies which I always appreciate very much!
Hereâ€™s what he had to say.
â€œIt is very unlikely to be WPW:
- the â€˜deltasâ€™ in in the mid praecordial leads, in the absence of deltas elsewhere, do not fit the usual patterns of preexcitation
- the septal q waves in V5 and V6 suggest that conduction to the septum is first i.e. the normal pattern, rather than preexcitation of the ventricle elsewhere (see referenceÂ here)
- it is not unusual to see a little slurring in some leads as appears in V3
On the other hand he has a number of interesting features:
- ST depression in aVR, the most specific ECG marker for pericarditis
- â€˜early repolarisationâ€™ in an infero-lateral pattern; once considered a normal finding, now known to be associated with SCD (although this isÂ weakÂ marker for sudden cardiac death; useful in populations, practically useless for predicting an individualâ€™s risk)
This case did make we wonder about the differential diagnosis for a slurred beginning to the QRS in precordial leads. Obviously WPW and the other preexcitation syndromes, HCM (read recently about one labâ€™s experience with patients referred with HCM for suspected preexcitation and not a single patient had an accessory pathway), presumably LVH, and intramyocardial conduction delay of whatever cause, and electrolyte abnormalities.â€
Pretty cool, huh? Thanks, Mark!
By the way, you can follow Mark the EP Fellow on Twitter here:Â @epfellow