COVID-19 disease is a highly inflammatory disease that can affect both the muscle of the heart (the myocardium) and the sack around the heart (pericardium). If it causes inflammation of the myocardium, the condition is called myocarditis (myo= muscle, cardio = heart, itis= inflammation). Patients with myocarditis are very vulnerable and can develop heart failure and life threatening arrhythmias that can cause sudden cardiac death. With myocarditis, a blood test called troponin I is elevated. Another blood test often used is called BNP (brain natriuretic peptide). A high BNP is a marker for congestive heart failure whereby the heart muscle fails to pump and fluid backs up into the lungs causing congestion.
Many viruses can cause myocarditis including the viruses that cause the common cold but the incidence is very rare. Sars-COV-2 , the virus that causes COVID-19 seems to do it more often. We don’t quite know how to treat COVID-19 myocarditis but since myocarditis caused by the other viruses is often treated with steroids so we use steroids. We also use diuretics. The prognosis of viral cardiomyopathy / myocarditis from other viruses other than COVID-19 seems to follow the rule of 1/3s. One third of the patients get worse and go on to develop severe heart failure needing a heart transplant, one third stay the same and require lifelong medication and one third get better and their heart normalizes. As with all other things of COVID-19, we don’t really know much about COVID-19 myocarditis and much research is needed.