I received a number of inquiries from blog readers today about the issue of myocarditis associated with COVID-19 infection.
Myocarditis is inflammation of the heart muscle that can cause dysfunction of the heart or even abnormal heartbeats that can lead to death. It can lead to heart failure and rob the body of blood flow necessary to keep the other organs alive. Myocarditis is associated with many viral infections, including flu, but it’s usually an uncommon complication.
In contrast, concerns have been raised because a number of papers have suggested myocarditis occurs in a very high percentage of young people who are infected with COVID-19, even if they have no symptoms.
This has been a confusing and potentially concerning topic for quite awhile. It created much consternation as it was one of the reasons given for canceling the Big 10 Conference football season. The issue was raised again yesterday because Dr. Wayne Sebastianelli, a physician at Penn State University, made comments suggesting that, ”35% of Big 10/ Penn State athletes were identified as having myocarditis in association with COVID-19 infection.”
This turns out not to be true. The physician and Penn State had to walk back and apologize for his comments today since they were entirely incorrect. In fact, the University now reports that, “At this time, there have been no cases of myocarditis in COVID-19 positive student-athletes at Penn State.”
What is actually documented about clinical myocarditis in COVID-19? There have been cases of clinical disruption of the heart with COVID-19 in 5-20% of patients with severe disease. Therefore, myocarditis is not just a theoretical complication of COVID-19. It needs to be searched for in patients who are very ill with COVID-19 and closely monitored if present.
The real issue is the frequency and severity of cardiac inflammation associated with COVID-19 infection, particularly in asymptomatic young people. The reports showing a high frequency of cardiac involvement (myocarditis) in COVID-19 have determined this simply by an imaging procedure which can suggest inflammation associated with the heart. These patients reported as having myocarditis on imaging are not clinically ill and do not have any clinical evidence of myocardial abnormalities. It is not clear that any of these individuals have clinical myocarditis as compared to abnormal heart imaging.
No other viral disease has been evaluated for myocardial inflammation in this manner. In addition, these are not blinded analysis, so the physicians know which patients have COVID-19 and which don’t. That can lead to misinterpretation of inflammation in ways that overstate the evidence of myocardial problems.
In this regard, Dr. Venkatesh Murthy, the Rubenfire Professor of Preventive Cardiology at the University of Michigan and an expert in cardiac imaging, has raised issue with how the most prominent study showing heart imaging abnormalities was performed.
The cardiac MRI study of COVID patients recently published in JAMA cardiology has a number of issues,” Murthy told Sports Illustrated. “The most serious of them are irregularities in the statistics which suggest either serious errors or perhaps even manipulation. These were identified by Prof. Darrel Francis and Graham Cole, cardiologists at Imperial College London.”
In addition, he was concerned that “even the controls they used seem to have very high rates of abnormalities like moderate to large amounts of fluid around the heart which would not be expected in normal individuals,” Murthy said.
“Finally, most of the abnormalities they identify have not been defined as medically important and may have limited or no long-term consequence,” Murthy said. “This is particularly a concern in elite athletes where many subtle abnormalities can be found either acutely after events like marathons or chronically with both blood tests and MRI scans. We don’t know if these are bad signs.”
In summary, myocarditis is a concern with COVID-19, particularly in patients with severe disease. However, there really is no evidence that it is a problem in young individuals with asymptomatic COVID-19.