Improving differentiation between Myocarditis and Myocardial Infarction to improve patient outcomes.

Dr Ashleigh Dind’s latest research is focused on better understanding the differences between myocarditis (inflammation of the heart muscle) and myocardial infarction (commonly known as a heart attack).

For these conditions, it is essential correct diagnosis is made swiftly, as urgent intervention is required and treatment differs.

Dr Ashleigh Dind is part of a research group with Professor Gemma Figtree (Cardiologist), Dr Rebecca Kozor (Cardiologist), Professor Stuart Grieve (Radiologist) and Professor Sharon Kay (Echo technician and Associate Professor).

Over the past 3 years this team, based at Royal North Shore Hospital, have been recruiting patients who either presented with myocarditis or myocardial infarction. They collected data on their blood tests and analysed their echocardiograms (heart ultrasounds) and cardiac MRIs. Valuable results were gained using the peak level of their blood test named ‘troponin’ and the severity of heart dysfunction and scar on their echos and MRIs.

In both myocarditis and myocardial infarction, patients present with chest pain, a rise in their troponin levels, and often ECG changes.

If the patient is having a myocardial infarction then time is critical as the blood supply has been cut off to the heart. An angiogram is required immediately to restore the blood supply.

In myocarditis, the patients do not gain benefit from an angiogram and they could be subjected to complications. An MRI is the best test to diagnose myocarditis, however cardiac MRIs are not usually available urgently. MRIs effectively differentiate myocarditis from infarction by illustrating the typical pattern of Late Gadolinium Enhancement (LGE). They highlight which region of the heart is inflamed, which is not seen on standard echocardiography.

Prior studies have generally found that peak troponin levels are greater in myocarditis compared to infarction. The results have been variable in determining if there is a relationship between troponin and LGE in myocarditis. Currently there is no data on differentiating myocarditis from infarction using the relationship between troponin and data derived from MRI or echo.

Research Impact

Both myocarditis and myocardial infarction are conditions commonly presented to hospital. The varying tests they require takes time, money and resources.

Patients with myocarditis are often younger, and may have had a viral prodrome prior to the onset of their chest pain. However, clinicians would not want to overlook a heart attack in these young, otherwise healthy patients so often refer them for an invasive angiography to check their coronary arteries.

This procedure comes with some risks such as bleeding, stroke or damage to the arteries. It does not diagnose myocarditis, it simply rules out infarction.

An MRI is required to diagnose myocarditis, but usually occurs days later as rarely available on an urgent basis.

Dr Dind aims to identify surrogate markers that can differentiate myocarditis from infarction to avoid invasive testing. Patients undergo a blood test confirming troponin levels and an echo promptly after presenting to hospital, so any additional information to help identify myocarditis could help avoid any risks of unnecessary invasive testing.

Conversely, if this information showed the patient was actually having an infarction, clinicians could expedite their angiogram and reduce any risk of further damage done to the heart.

Dr Dind and her team have commenced analysing peak levels of troponin in the blood of their research patients and have compared that to the heart function and amount of inflammation (LGE) seen on cardiac MRI.

To date, they have found that patients with infarction have greater heart dysfunction and greater amounts of inflammation in their hearts compared to patients with myocarditis.

Patients with infarction also have a higher troponin levels for the same amount of heart dysfunction and LGE.

The next step in Dr Dind’s research is to use EchoInsight (strain) software, funded by Heart Research Australia, to analyse the patients’ MRIs and echos.

Prior research predicts that the inflamed areas of the heart (seen as LGE on MRI) will produce abnormal strain measurements. Strain is a way to measure dysfunction that cannot be seen with the naked eye.

Assessing for regional abnormalities instead of global abnormalities which are often subtle, can show a distinct difference between patients with myocarditis and myocardial infarction so patients can avoid invasive and unnecessary tests in the future.

To read more about Myocarditis click here.

To read about more research we are funding click here.