Cardiac Question re: pericardial effusion

[Cranny]

I have a moderate pericardial effusion. No symptoms, and no apparent danger of complications (tamponade) as best as we can tell. May be chronic; we don't know. Is this a contraindication for diving? Is there any knowledgeable specialist I can contact?

[Duke Dive Medicine]

Cranny,
Because of the way the blood gets redistributed when you're immersed, even a moderate pericardial effusion can affect your cardiac output while diving. With no more info than what you've posed, I'd say you should not dive until you figure out not only what's causing the effusion, but also how it's affecting your heart. Dr. Doug Ebersole, screen name debersole, is a cardiologist and probably your best source for cardiac-related info here. I don't want to speak for him but he's always been very responsive to private messages and forum postings.
Best regards,
DDM

[TSandM]

The biggest functional issue with a pericardial effusion is that the fluid can create a kind of compressive phenomenon, where the heart cannot fill properly because space within the pericardial sac is being occupied by the effusion. This means that, to get the same cardiac output, you have to run a much higher pulse rate, and that's hard work for the heart.

It isn't always true; if the effusion has accumulated slowly and the pericardium (which is not very elastic) has slowly stretched, you can have a huge cardiac silhouette on chest x-ray, and a normal-sized heart within it.

But DDM is entirely correct; the focus right now should be on diagnosing WHY you have a pericardial effusion, and what, if any effect it is having on your cardiac performance. Effusions are neither normal nor common, and a wide variety of conditions can cause them. It's important to figure out what is doing this, because there are effective treatments for some of the causes.

[Cranny]

Thanks to you both for your thoughtful answers, and useful suggestions. I will definitely follow them. I suspect the cause of the effusion will likely remain unknown; we've had a fairly thorough workup without any definite cause found. As we have only one ultrasound reading, we don't have even two data points, so we can't tell if chronic or acute. No hemodynamic compromise or impending tamponade, however. Stress ECHO went well, also. Until we see whether it is resolving or not, no diving for me, I guess. Bummer.

[TSandM]

I suspect, if it is chronic and stable, you will get back to diving; also if it resolves. Please come back and let us know how it goes!