Somehow I find myself cornered into being a world expert on everything.

(My daughter used to believe that. But that was when she was three after a remorseless campaign of me emphasising that point.)

In my simplistic view, Myocarditis is like a bruise.

If someone punches you in the arm, you will get a bruise, and it will eventually get better (unless you die from complications of a broken bone).

During the immediate few days after the punch-ment, there will be:

Raised CRP
Raised CK from the traumatised muscle
It will probably hurt a lot.

Then it will get better and go away.

I am sure the MRI docs will have a way to scan the arm, to show some bruisification pictorially.

And I suspect it will hang around a lot longer than the blood tests.

Because even after the muscle membranes have restored themselves, so you are no longer releasing muscle proteins, there is still left-over oedema, bits of blood and whatnot, hanging around, available to be picked up on a scanner.

I am GUESSING that almost all of the imaging features will fade away with time.

But who knows, some signs may hang around for ever.

(The example I give is a grazed knee - technically you are scarred for life, but you don't get life trauma over it: mummy just kisses it better.)

ON THE OTHER HAND there are groups of people who have bruising without being punched in the arm.

Who?

People with cancer.

People with haemophilia and other such diseases of disordered coagulation.

If you take 1000 people with cancer and divide them into two groups, say:

"People with spontaneous bruising"

and

"People without spontaneous bruising"

Who do you think would have the worse long term outcome from cancer?

Yes, because the "non bruising" group will contain LOTS of people with very mild cancer.

A tiny basal cell carcinoma here
A small prostate neoplasm there
etc.

And many people with widespread metastases and bone marrow involvement will be in the bruising group.

So Francis Industries MRI Bruise-Ometer, will correctly claim that it can predict prognosis from bruising.

"My indices of Brusing, B1 and B2, predict 5 and 10 fold risk of death, respectively!"

"Fear the B1"

"Tremble at the mere mention of B2"

Now, suppose there is a worldwide epidemic of punching people in the shoulder.

NOW Francis Industries kicks into high gear, and starts diagnosing elevated B1 and B2 all over the place.

We are 100% correct, there is bruising.

But it is not people being about to die, from self exploding muscles.

It is people recovering from being punched in the arm.

Does that help?

A test may be a bad warning sign in one condition, but not in another condition.

As you can see here, the Late Gad, which we used to think of as permanent, arises in about 1/3 of severe SARS patients, and seems to fade away with time.

https://sci-hub.tw/10.1016/j.jcmg.2010.08.021

As for myocarditis, the term is used as variably as the term "bruise".

It generally means that something is irritating the heart, and that cells are releasing some of their internal protein. Our tests are EXTREMELY sensitive and pick up even miniscule protein leaks.

On the other hand, even after the protein has stopped leaking, because you are no longer at death's door, there may be things detectable in the scan that have not got better yet.

Do you have myocarditis then?

With the blood tests all back to normal?

I would say "No".

Others would say "Yes"

That is enough to produce a massive range of percentages-with-myocarditis.

So I don't worry about different percentages.

It is perfectly par for the course.
In science we are quite relaxed about these things.

Oh hello!

Didn't take long for Troponin to be linked to bad outcomes in Covid.

Uncle darrel's rule

Every feature of a disease
Is a prognostic marker of that disease. https://www.medscape.com/viewarticle/936868