Hello @pearlumie, thanks for your comment! Indeed there are some ways to know the severity of this affliction: studies similar to the ones performed during a heart attack.
An electrocardiogram to help study if the electrical current passing through the cardiac muscle is is any way being altered, which would be a good indicator of severity, an angiography to visualize the flow of blood through the heart's coronary arteries and see if it is diminished (which is often what causes the pain patients experience), and blood tests looking for cardiac enzimes that only appear when part of the cardiac muscle begins to die; I they are present, it means that the condition is serious and may cause lasting sequels.