Respiratory Failure, Heart Failure, and Narrow Complex Tachycardia
Posted Sep 15 2011 10:09pm
A 60 yo female presented by ambulance in resp distress, requiring noninvasive ventilatory support. She had pulmonary edema and was near respiratory failure.
Here is the prehospital ECG (will not comment on the interpretation until the end of the post, so you can ponder it for yourself)
Computer read: "Sinus tachycardia" at a rate of 143, and "***Acute MI***". Obviously, there is no clear STEMI.
She was continued on respiratory support, treated for COPD and CHF with nebs, steroids, lasix and nitro. Here is her first ED ECG
The computer reads "sinus tach".
An ED bedside echo was performed from the subcostal view:
Here is a legend for what you are seeing on the echocardiogram: LA = Left atrium, LV = left ventricle, RA = right atrium, RV = right ventricle, MV = mitral valve. The LA is greatly enlarged. The LV is very small. The mitral valve is very echogenic and highly suggests stenosis, which we confirmed with doppler.
Chart review confirmed h/o porcine mitral valve replacement with subsequent development of prosthetic mitral valve stenosis (that is to say, it recurred in the new valve). This conforms with our ED echo.
The heart rate continued at 143, and by this time there was much less artifact. This strip was printed out
Now there is clear atrial flutter.
A bit of history could be obtained at this point, and she said she had had rather sudden SOB about 15 hours prior, and had had some pink and frothy sputum.
A better 12-lead was obtained
Now, again, the atrial flutter is obvious, and there are no signs of ischemia
So, we have a patient who is in respiratory distress, due to mitral stenosis and complicated by atrial flutter, which diminishes LV filling that is already compromised by mitral stenosis. ACLS would say to do electrical cardioversion for a patient with atrial flutter and rapid ventricular response who is suffering respiratory failure, but patients with mitral stenosis are at very high risk of thromboembolism and stroke (old literature). Cardioversion would increase this risk. Therefore, we decided on slowing the ventricular rate with diltiazem. Here is the subsequent ECG
There is now atrial flutter with 4:1 block.
With more time to fill, the LV was able to pump better. The patient improved gradually, and refused a valve replacement. She returned a few days later in distress and will now get a new valve.
Look again at the first ED ECG
Knowing that it is atrial flutter, you can now see (if you didn't before) the atrial spikes in V1 (2:1) that might have been interpreted to be artifact.
Learning points1) When the heart rate does not change, but stays rapid and constant, it is probably not sinus tachycardia and then you should... 2) Look for atrial flutter waves 3) ACLS is guidelines only. Sometimes the patient does better with less aggressive care (and, of course, sometimes with more). One must always think it through. 4) Bedside echo can be very useful