Long-Long COVID and Myocarditis:
How to Recognize Your Risk

Myocarditis is an inflammatory disease of the heart muscle: pathogens — predominantly viruses — attack the heart muscle tissue, which can lead to its destruction.

The nature, severity, duration, and resulting condition of this heart inflammation vary greatly from person to person, making the course and prognosis of myocarditis difficult to predict. Some cases go unnoticed by the affected individual and heal on their own. Acute myocarditis is the classic form, where heart function is significantly impaired. In chronic myocarditis, the inflammatory processes in the heart tissue persist to varying degrees.

There are no typical symptoms of myocarditis: the initial signs are often masked by general infection symptoms. They are usually not linked to the heart, especially if symptoms like fever, dizziness, muscle aches, or diarrhea persist or reappear after the actual infection seems to subside. Shortness of breath during exertion, rapid heartbeat, irregular heartbeat, and unexplained fatigue or exhaustion are also important warning signs.

As non-specific as the symptoms may be, diagnosing mild forms of myocarditis is especially difficult. To investigate a suspected case, an electrocardiogram (ECG) is primarily used.

Myocarditis is most commonly triggered by viruses. Researchers at the German Centre for Cardiovascular Research have demonstrated in the lab that the coronavirus can also enter heart muscle cells. Cardiologists have also detected the virus in tissue samples (myocardial biopsies) from COVID-19 patients. Additional research data has increasingly confirmed the suspicion that the virus can directly cause damage to the heart.

However, the exact risk of developing myocarditis — especially with lasting cardiac damage due to COVID-19 — is still unclear.

There are several possible explanations for the cardiac damage observed so far. These range from direct viral infection, to plaque rupture due to systemic inflammation, to severe hypoxia/hypoxemia. All of these underlying mechanisms can potentially result in an acute heart attack, heart failure, arrhythmias, or myocarditis.

Existing data suggest that the risk of severe (acute) heart damage from a COVID-19 infection is significantly higher than from vaccination with an mRNA vaccine. This has been shown, for example, by an analysis of data from around 1.7 million people in Israel, both vaccinated and unvaccinated.

Experts therefore recommend that even patients who had a mild case of COVID-19 undergo a follow-up examination several months after recovering. The virus is still too new for all long-term effects to be known. For this reason, medical monitoring is especially important. An electrocardiogram (ECG) can provide clarity about heart health.

In patients with noticeable symptoms of myocarditis, three main treatment goals are pursued:

• Stabilizing the heart’s pumping function by supporting and relieving the heart muscle through appropriate medications
• Combating the inflammatory process to minimize damage to the heart muscle
• Treating residual and long-term effects to prevent the inflammation from progressing

Rest is always recommended: Intense physical activity should be avoided for about six months following a suspected myocarditis, and only resumed after a follow-up cardiological examination with normal findings.

The long-term prognosis after an acute, uncomplicated viral myocarditis is generally positive. Around 70 percent of patients achieve full recovery. Some patients may experience mild lingering symptoms caused by scarring of the heart muscle, such as minor cardiac arrhythmias.

For individuals with pre-existing advanced heart failure, the outlook is significantly worse. Approximately 15 percent of these patients develop chronic forms of the disease, which in rare cases can lead to progressive and irreversible heart failure.