Saturday, November 19, 2011

Tachycardia with Pericardial Effusion

A 52 year old man with a history of atrial fibrillation and prosthetic mitral valve replacement just 11 weeks prior presented with a complaint of a rapid regular heart rate; he could hear rapid clicking of his valve.  He was otherwise asymptomatic.  His medications included amiodarone for rhythm control of his atrial fibrillation.  This ECG was recorded:
The treating physicians diagnosed sinus tachycardia at a rate of 127.  They were worried about ST elevation in II, III, and aVF, with reciprocal ST depression in I and aVL.  With the Q-waves, they were not sure if this was old or new ST elevation.

They looked for a previous ECG and found this:
There was no ST elevation at baseline.  They were now worried about acute MI.

They did a bedside echocardiogram and found a large pericardial effusion.  BP was stable and normal at 110/83.  They infused a liter of normal saline, and the heart rate remained 127.  A repeat ECG was identical.

70 minutes after arrival, the first troponin I returned elevated at 0.160 ng/ml.  Now they were even more worried about MI. 

What is the diagnosis?

Slow Atrial Flutter with 2:1 conduction.  Slow because of the beta blocking effects of amiodarone. 

1.  Note the flutter waves in V1: one positive wave that appears to be a p-wave and another that immediately follows the QRS.  The one that looks like a p-wave is positive, whereas the p-wave on the previous ECG is negative!
2.  Any time the heart rate remains the same, in spite of time or fluids, it is almost certainly not sinus.
3.  There is no ST Elevation.  All of the apparent ST elevation is due to the baseline formed by the atrial flutter waves!

INR returned at 3.9.  The patient was given propofol and electrically cardioverted in the ED.  Here is the subsequent ECG:

Final diagnosis: Atrial flutter with pericardial effusion due to myocarditis due to postoperative Dressler's syndrome.  Troponin elevation from demand ischemia.  ST elevation from flutter wave.  The effusion disappeared with time; no surgery or drainage was necessary. 


  1. Hi Dr. Smith

    Is there "electric alternans" in ECG1 ?


  2. There is some wandering baseline, but I don't see electrical alternans

  3. hi dr smith , is there is risk from DC crdioverting what you think it is atrial flutter and appear to be sinus tachy ?? or if you suspect it is flutter you shock the patient if unstable ??

    1. There is a very small risk of v fib any time you shock, but if you're prepared to defibrillate, that should not be a big problem.


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