No cardioversion due to risk of embolism?

KBICU · May 12, 2013

35 yr old female comes in crying, anxious, coughing. States her chest hurts. Hx of Graves disease. EKG shows SVT 240's. RR 40's, and BP 140's/100's.We get her ready for a dose of adenosine, doc walks in and starts asking his questions. She says she has felt like doo-doo for the past 2 days.
6mg adenosine without effect.
20mg diltiazem brings HR to 200.
5mg lopressor drops HR to 180.
She's on the pads, about to cardiovert, doc tells us to stop until we get a CT angio due to "risk of a clot" because "she's been like this for the past 48 hours. She has chest pain, she could have a PE."
What?
I'm sure she has been in SVT for the past 2 days. And I'm sure her chest hurts cause she is throwing a clot, nothing to do with her HR or BP. And I bet she is in a thyroid storm.
1.5 hours later, after we get labs back and get the CT angio is negative, cardioversion is successful, she sits at sinus tach at 110 until she is admitted.
My question is: have you ever not performed a cardioversion due to risk of a clot? I mean, we tried 3 different meds with limited success. No place else to go than cardioversion. I was upset we didn't cardiovert right off the bat.
BTW, this is the first time I have seen absolutely no effect from adenosine, and yes we gave it properly.

I have seen MDs not do CVSNs may times because of this reason. If the patient had a clot in the atria and you cardioverted them, you'd throw the clot into the lungs and possibly be a lot worse off. You could try adenosine up to three times (12mg the next two times) and continue med management if CVSN wasn't a possibility. If the patient is in the rhythm for an unknown amount of time, what the doc did is a very common course of action.

psu_213, BSN, RN · May 12, 2013

Would the CTA show a clot in the atria? I know the gold standard to check for an clot before cardioversion is a TEE. Does at CTA serve the same purpose? In addition, if the clot is already in her lungs (which would show up on the CTA), would there be more harm if they did the cardioversion?

A couple other questions of curiosity: did the doc check renal labs before the CTA? Do they have to? She is only 35, but our CT policy is not to check Cr before any use of CT contrast. Based on lab work, was the pt in thyroid storm?

KBICU · May 12, 2013

Would the CTA show a clot in the atria? I know the gold standard to check for an clot before cardioversion is a TEE. Does at CTA serve the same purpose? In addition, if the clot is already in her lungs (which would show up on the CTA), would there be more harm if they did the cardioversion?
A couple other questions of curiosity: did the doc check renal labs before the CTA? Do they have to? She is only 35, but our CT policy is not to check Cr before any use of CT contrast. Based on lab work, was the pt in thyroid storm?

I've never seen a CTa for checking an atrial embolus but your right that he was using that to check for PE. I cant really think of a reason why a CT wouldn't show the clot but it would depend where it was i suppose. I agree that TEE is usually used to check the back of the heart for embolus...does the OP know why they didn't go this route? I'd have to hear more about the patient

Altra, BSN, RN · May 12, 2013

Yes, I think the doc's concern was appropriate. And I disagree that it is likely that she had maintained a HR in the 200s for 48 hours ... even a young person is unlikely to tolerate that rate for that long. And I have seen adenosine fail to convert a rhythm.

KBICU · May 12, 2013

That reminds me, I've heard from intensivists in the past that if adenosine fails to convert SVT it's not true SVT. Anyone heard this before?

psu_213, BSN, RN · May 12, 2013

That reminds me, I've heard from intensivists in the past that if adenosine fails to convert SVT it's not true SVT. Anyone heard this before?

If I remember from my first ACLS course correctly...if adenosine converts the SVT, it is d/t a reenterant pathway (I guess this is what is meant by "true" SVT). If adenosine does not covert the rhythm, it is another type of SVT--such as a fib with RVR or a very fast sinus tach.

KBICU · May 12, 2013

http://old.ctisus.com/cta_web/12_05/pdfs/AR_12-05_CTA_Poon.pdf

rjflyn, ASN, RN · May 12, 2013

But doesnt ACLS also say a pt with chest pain and a heart rate in excess of 150 is by definition unstable and waiting around for a hour and a half for a test probably isn't the greatest course either. I for one want to know what the cardiologist he talked to said.

allnurses Guide · May 12, 2013

I have seen CTs done prior to cardioversion for this reason.

CodeteamB · May 12, 2013

I have several questions. Was the adenosine being used in an attempt to cardiovert or was it diagnostic (I'm figuring the latter since only one dose of 6 was given).

If this was the case it makes more sense to me. In my understanding converting the heart to a normal rhythm with a clot in the atrium will have the same effect whether you do it with medication or electricity.

I also have never seen a CTA to look for clots in the atrium, but you say there was concern that she already had a PE, so was the CT maybe for that? I guess the CTA would also show an atrial clot as BostonFNP has seen it done.

Our policy is that if we can identify onset within the last 48 hours we will cardiovert, otherwise our physician will get an echo first, and yes this is common.

allnurses Guide · May 12, 2013

I have several questions. Was the adenosine being used in an attempt to cardiovert or was it diagnostic (I'm figuring the latter since only one dose of 6 was given).
If this was the case it makes more sense to me. In my understanding converting the heart to a normal rhythm with a clot in the atrium will have the same effect whether you do it with medication or electricity.
I also have never seen a CTA to look for clots in the atrium, but you say there was concern that she already had a PE, so was the CT maybe for that? I guess the CTA would also show an atrial clot as BostonFNP has seen it done.
Our policy is that if we can identify onset within the last 48 hours we will cardiovert, otherwise our physician will get an echo first, and yes this is common.

It's not ideal but there have been a few studies on cardiac CTs for eval of LAATs