What is your approach to treatment of pericardial effusion secondary to atrial tear?

RE: What is your approach to treatment of pericardial effusion secondary to atrial tear?

Roger Wilkinson — Tue, 03 Nov 2020 14:28:45 GMT

A handful of the published cases were drained...but vast majority not. Difficult to even extrapolate from human medicine in this case because analogous presentation doesn't arise except in exceptional circs as far as I can see. Traumatic atrial ruptures in people usually accompanied by pericardial perforation and basically it's surgical can be rescued from acute event.

RE: What is your approach to treatment of pericardial effusion secondary to atrial tear?

Mark Patteson — Tue, 03 Nov 2020 12:46:47 GMT

I am happy for you to quote me although if it gets any more hairy with this owner, I suggest speak to our VDS colleagues and copy all the images

I don't think that LA tears are that common, although also suspect that they get missed.

Identifying tamponade isn't as black and white as some people would have you believe, so the decision making is multifactorial

we can only account for what we do ourselves so if soeone else decides they know better so be it, with thsi sort of case its not hard and fast but I don't ever recall draining an LA tear

Mark

RE: What is your approach to treatment of pericardial effusion secondary to atrial tear?

Glen McIntosh — Tue, 03 Nov 2020 12:31:35 GMT

Thanks Roger and Mark, that’s very helpful.

In my role as an emergency vet, one of my main concerns in these types of cases is whether or not to perform pericardiocentesis. The case I have described above was referred specifically for emergency pericardiocentesis, and the owner was advised by their regular vet that this was needed urgently and that the dog would certainly die without it.

My advice to the client was actually not to attempt pericardiocentesis because I was a concerned about possible atrial tear in this type of presentation (small breed, heart disease, massive LA) and if this was the case then pericardiocentesis had a high chance of leading to exanguination and death. Certainly I have had this happen in one or two cases with this type of signalment and presentation before the penny dropped and I became aware of the less common cause of pericardial effusion from atrial tear. Since then this is the one type of presentation of pericardial effusion I would be very reluctant to attempt to drain, and have seen several of this type of presentation recover and be discharged with medical treatment and no drainage. I guess I was looking for views from cardiologists about whether they would agree with that approach or not.

For this case I just monitored the dog in oxygen and started pimobendan. The dog was pretty stable overnight, perhaps even showing mild improvement. I had advised cardiologist referral the following day, but the owner wasn’t particularly happy with my advice and I understand that they transferred to a vet who had agreed to perform pericardiocentesis. I don’t know what happened to the dog in the end.

RE: What is your approach to treatment of pericardial effusion secondary to atrial tear?

Mark Patteson — Tue, 03 Nov 2020 12:03:33 GMT

I agree with Roger on this one

And there are times where none of us can be sure if its a tear (however pesky we are). You may need a variety of views and they most often tear dorsally so have a good look around the roof of the LA which will be outlined by the PE
we assume that the ascites is right sided failure, but you can check the jugular (probably distended) , hepatojugular reflex (+ve) and scan the hepatic veins (distended) to be sure

I agree that L-CHF due to MMVD is most likely and often that means that he ascites is due to pulmonary hypertension (PHT) But in this case, as the output is low I wouldn't assume that and I would need a detailed Doppler assessment to be sure. This is almost the most useful feature of Doppler in acquired disease in dogs - but you need to measure the TR velocity accurately (the jet may go in odd directions) and you need to be well aligned. A low-frequency probe may help. The machine will do the maths for you (you don't need to remember the Bernouilli equation) and give you an estimate of systolic PA pressure Should be less than 30mmHg (sometimes 35 to be safe) If clinically relevant often it's> 45, if you are rocking and rolling with the Doppler you can estimate the diastolic pressure by measuring the PR gradient(should be less than 20)

as for treatment, it's hard because you may not be able to be certain and there is also a wish that you have to give something, when in fact you may be best to sit it out.
I use amlodipine to unload LA pressure in some cases and might here, but it would depend on the systolic systemic pressure if it's < 100 I would avoid (and it's not needed anyway) I sometimes use this in acute L CHF but in hospitalised patients . We used to use hydralzine for the same reason but I prefer amplodipine

with ascites dont feel you need to get rid of every last drop, the dog will feel fine with some fluid and if you over diurese you wil reduce cardiac output. so dont go data sheet doses of frusemide until it's gone, it will be too much.

whatever you decide to do, no one can prove you're wrong becasue there is almost no data on this - these cases are all a bit different and its a case by case clinical judgement call

I supect the dog is now either better or dead, but I hope this is useful for next time

Mark

RE: What is your approach to treatment of pericardial effusion secondary to atrial tear?

Roger Wilkinson — Mon, 02 Nov 2020 22:08:25 GMT

Hi Glen,

I'm always conscious that my answers on here are never as good as those pesky diplomates. However, since no one else has jumped at it I'll start the ball rolling because it's interesting....but you should maybe regard this as exploratory thoughts.

I agree it's worth weighing up the possibility of pericardial effusion due to CHF and then transient weakness due to some other factor (PTE?, arrhythmia? chorda rupture? even anaphylaxis?). R CHF due to PTE or ruptured chordae and anaphylaxis would all be potential alternative causes of acutely reduced cardiac output in association with ascites obvs. And although ascites has been a feature in some published cases of L atrial rupture, my experience is that it's not common to see it developing acutely in association with the haemopericardium.

If the tamponade isn't convincing I'd be inclined to consider R CHF due to pulmonary arterial hypertension a plausible cause of ascites. Since I think in dogs it's conventionally R CHF which is regarded as the likely cause of CHF-induced PCE, it's plausible that PCE could be another manifestation of R CHF along with ascites etc.

In this case would probably be R CHF secondary to L CHF-induced pulmonary arterial hypertension. A R sided murmur of tricuspid regurg would increase index of suspicion of R CHF due to PAH.

The presence of a convincing thrombus in the pericardial sac and/or on the inner aspect of the LA at the site of tear has, previously, been considered by some authors almost a prerequisite for a diagnosis of L atrial tear. However, as I understand it, that's not necessarily always the case. Perhaps absence of thrombus increases suspicion of another cause of PCE though.

Generally-speaking if it were a LA tear then, in acute scenario, there are conflicting needs to limit left atrial pressure to reduce haemorrhage vs need to maintain cardiac output. I'm not sure that's an exact evidence-based science. Probably if the tear is really big then they're beyond anything medical treatment can do and probably most do die before reaching an echocardiogram.

Most of the ones I've seen are at least a few hours down the track and the fact that they've lasted that long has filtered out those that haven't stopped bleeding. Once they reach some kind of stability like that then to be honest I usually just try to manage the congestive failure as per normal once they are back on their feet and BP stable. There's obviously an option to give fluids in the early stages if BP is low and there isn't evidence of pulmonary oedema.

There is some published evidence that dogs surviving the first collapse can have reasonable survival times

median 200 days in this series: pubmed.ncbi.nlm.nih.gov/.../

Decision-making gets easier after a few days. If BP lowish initially then I'd certainly tolerate a bit of ascites until then before trying to diurese harder.

hope that stimulates some debate -even if only people correcting me!

Roger