The clinical features of myocarditis are widely ranging. You can have, for example a completely asymptomatic
patient who’s got really a subacute infection to someone who’s got a rapidly fatal fulminant myocarditis
with heart failure. When should your clinical suspicion be aroused, unexplained heart failure, for example
in a young person, someone with no predisposing problems like hypertension, myocardial infarction.
Also, you should suspect it in somebody who’s got chest pain. It can actually mimic the pain
of acute myocardial infarction. Someone who comes in with a supraventricular tachycardia,
they’ve never had problems with arrhythmias before. Now, they’ve got a rapid heart rate with multiple
ventricular extrasystoles. That just doesn’t happen in normal individuals; or cardiac abnormalities developing
during a recognized systemic infection. So a patient comes in, for example, the typical viral syndrome
and then they proceed to heart failure, arthralgias, respiratory symptoms along with it.
So, how do you make the diagnosis? Well, it’s usually a diagnosis that’s presumptive based on
the patient’s age, exposure history, and the clinical course. The workup would include a CBC.
It would be rheumatologic screening to rule out connective tissue diseases. Certainly, you want to get
cardiac enzymes including troponin I. An echocardiogram is definitely indicated to look for other causes,
valvular, congenital, amyloid heart disease. When available, you would want to get serum viral antibody
titers, acute and convalescent. There is available non-invasive cardiac imaging. For example, cardiac MRI
can reveal changes within the myocardium itself consistent with viral myocarditis. We are now doing
more and more endomyocardial biopsies with viral genome testing. But the problem with that is
you do that through a catheter and there’s sampling error that may be involved. Obviously, you want to
follow and monitor the electrocardiogram. How do you manage myocarditis? It’s essentially supportive
therapy in hemodynamically stable patients. The patients who have heart failure have to be given
ACE inhibitors, β-adrenergic blockers. There’s some evidence that β-blockers may decrease inflammation.
Anti-viral therapy, much as we’d like to have it has very limited applications in myocarditis.
I’m not aware of any studies showing efficacy in a major way of any anti-viral drug.
For Trypanosoma cruzi, Chagas disease, we use anti-trypanosomal therapy which includes
benznidazol and nifurtimox. You may get substantial resolution of this problem with these agents.
Immunosuppression has been tried but it certainly could not be considered useful routinely.
There are too many problems with immunosuppression especially with agents like corticosteroids
which may cause retention of fluid, aggravate heart failure. With things like methotrexate
and other chemotherapeutic agents that suppress the immune system, we are just not,
they’re not ready for prime time, not ready for routine use. That concludes my discussion of myocarditis.
I hope it was somewhat helpful to you.