Myocarditis is inflammation in the heart muscle. This is generally of infectious origin. Myocarditis is asymptomatic and benign in the majority of cases. Nevertheless, medical supervision is recommended to prevent the risk of serious cardiovascular complications.

Definition of myocarditis

Myocarditis is an inflammation of the myocardium, which is inflammation of the muscle tissue of the heart. This inflammatory reaction affects the functioning of the heart muscle. It remains benign in the majority of cases but requires hospitalization to prevent the risk of serious cardiovascular complications. 

Causes of myocarditis

Myocarditis is usually infectious in origin.

It is often caused by a viral infection of the respiratory tract or gastrointestinal tract. The viruses involved are in particular:

• influenzae viruses, or influenza viruses;
• echoviruses, which may for example be the cause of angina;
• the human immunodeficiency virus (HIV) responsible for AIDS;
• herpes viruses;
• etc.

Infectious myocarditis can also be caused by bacterial infections. The bacterial strains involved are in particular:

• Mycobacterium tuberculosis, bacterial strain responsible for tuberculosis;
• Borrelia burgdorferi, strain involved in Lyme disease;
• Mycoplasma pneumoniae, strain responsible for pneumonia.

In a few cases, myocarditis can be caused by a fungal or parasitic infection. The parasite Trypanosomia cruzi responsible for Chaga disease may in particular be involved.

Beyond the infectious origin, myocarditis can sometimes be due to:

• certain anticancer drugs (anthracyclines and cyclophosphamide);
• toxic agents like cocaine, amphetamines, etc. ;
• heavy metals including lead and copper;
• poisons including some venoms;
• radiation;
• vitamin deficiency including that of vitamin B1;
• etc.

Diagnostic of the myocardite

This inflammation is generally suspected by clinical examination and then confirmed by in-depth examinations. Healthcare professionals can in particular rely on:

• an electrocardiogram (ECG);
• blood tests;
• echocardiography;
• magnetic resonance imaging (MRI);
• a heart biopsy.

People affected by myocarditis

The incidence of this inflammation is difficult to estimate because many cases go undiagnosed. Myocarditis can remain asymptomatic (without apparent clinical signs) and resolve spontaneously. Conversely, there are severe cases that can present serious complications and require urgent medical care.

Myocarditis is asymptomatic in many cases. These cases are mild and can heal spontaneously.

Some flu-like symptoms can be seen:

• generalized weakness;
• fever;
• headache ;
• etc.

In the most severe cases, myocarditis may be accompanied by other symptoms such as:

• chest pain;
• arrhythmia, which is an irregular heartbeat;
• palpitations;
• dyspnea which results in difficulty in breathing;
• etc.

Myocarditis is a condition that resolves spontaneously in the majority of cases. However, this needs to be monitored in order to avoid the development of more serious complications. Hospitalization between 24 and 48 hours may be recommended. Rest is also recommended to allow the body to recover.

Depending on the case, the management of myocarditis may be based on:

• anti-inflammatory treatment;
• analgesic treatment;
• anti-infective treatment;
• immunosuppressive therapy;
• the use of pacemakers in severe cases;
• heart transplantation in severe cases.

Myocarditis can have many different causes. Among these, some can be avoided. For example, vaccination against influenza and tuberculosis can prevent some cases of myocarditis.

In general, it is also recommended to maintain a healthy lifestyle with good eating habits and the practice of regular physical activity. The consumption of toxic substances should be avoided.