Brief overview
- Symptoms: Often no or hardly noticeable symptoms such as increased palpitations (heart palpitations) and heart stuttering; possibly chest pain, heart rhythm disturbances as well as signs of cardiac insufficiency in advanced myocarditis (such as water retention in the lower legs).
- Treatment: Physical rest and bed rest, possibly medications such as antibiotics against bacteria; treatment of complications (e.g., heart-relieving medications for heart failure)
- Causes and risk factors: Infectious myocarditis, pathogens such as viruses (e.g., cold, flu, herpes, measles, or coxsackie viruses) or bacteria (e.g., pathogens of tonsillitis, scarlet fever, diphtheria, or in blood poisoning); noninfectious myocarditis, due to faulty immune responses, radiation therapy, or medications
- Complications: Pathologically enlarged heart muscle (dilated cardiomyopathy) with chronic heart failure, severe heart rhythm disturbances, sudden cardiac death.
What is myocarditis?
In heart muscle inflammation (myocarditis), heart muscle cells and often also the surrounding tissue as well as the blood vessels supplying the heart (coronary vessels) are inflamed. In addition to the inflammation, myocarditis is defined by the fact that the heart muscle cells regress (degenerate) or even necrosis is present – i.e. the muscle cells die.
If the inflammation also spreads to the pericardium, doctors call it peri-myocarditis.
What are the symptoms of myocarditis?
In fact, these complaints are often the only signs at the beginning of acute myocarditis. Symptoms such as loss of appetite and weight and radiating pain to the neck or shoulders are sometimes added.
If you develop possible symptoms of heart muscle inflammation days or weeks after a flu-like infection, be sure to contact your doctor!
Heart symptoms
Normally, a healthy person does not feel their heart. However, some sufferers notice increased palpitations during heart muscle inflammation. Some also report a feeling of tightness in the chest (atypical angina) or heart stumbling. This stumbling expresses that the heart is briefly out of step every now and then:
In the case of myocardial inflammation, either additional electrical signals are generated or their normal transmission is delayed. Sometimes the impulses are even not transmitted from the atrium to the ventricles at all (AV block). The normal heart rhythm is consequently disturbed. This causes heart palpitations (tachycardia) or irregular heart rhythm with interruptions in some cases of myocarditis.
How is myocarditis treated?
The treatment of myocarditis depends on the symptoms on the one hand and on the trigger on the other. Physical rest and treatment of a possible underlying disease are the cornerstones of myocarditis treatment.
In the case of very severe myocarditis, the patient is usually treated in the intensive care unit. There, specialists continuously monitor vital values such as heart activity, pulse, oxygen saturation and blood pressure.
Physical rest
In case of severe myocarditis, patients are usually hospitalized.
Even weeks after the acute phase of the disease, the patient must not overexert himself. The doctor decides when full exertion is possible again. As long as there are signs of heart failure, the patient is unable to work and is considered ill. If he exerts himself again prematurely, he risks a relapse and permanent damage.
If myocarditis requires prolonged bed rest, there is a risk of blood clots forming (thrombosis). Patients are given anticoagulants to prevent this.
Treatment of the cause
The most common causative agents of infectious myocarditis are viruses. However, there are usually no antiviral drugs available to treat such viral myocarditis. Treatment in this case essentially consists of rest and bed rest to help the immune system fight the pathogens.
In certain cases, other therapies may be considered for myocarditis (in some cases only in the context of studies). One of these is the administration of cortisone. It has an anti-inflammatory effect and suppresses the immune system. This is useful in autoimmune myocarditis, in which the body forms antibodies against the body’s own structures (autoantibodies) due to a misregulation of the immune system.
Treatment of complications
A possible complication of myocarditis is heart failure. Then the doctor prescribes various drugs, for example, ACE inhibitors, AT1 receptor antagonists or beta blockers. They relieve the weak heart. Diuretics do the same thing.
If fluid has accumulated in the pericardium (pericardial effusion) during myocarditis, the physician may aspirate it with a thin, fine needle (pericardiocentesis).
If the heart is so severely and permanently damaged as a result of myocarditis that it can no longer perform its function, the patient will most likely need a donor heart (heart transplant).
What causes myocarditis?
In terms of causes, a distinction is made between infectious and non-infectious myocarditis.
Infectious myocarditis
Physicians refer to myocarditis as infectious when pathogens are the cause. In around 50 percent of cases, these are viruses. Such viral myocarditis is often preceded by a banal viral infection (cold, flu, diarrhea). The coxsackie B virus in particular is often the trigger of viral myocarditis.
When viral myocarditis is suspected, doctors only determine the causative virus in exceptional cases. This would be of little practical use – there are usually no specific drugs against the viruses in question.
Some bacteria also trigger myocarditis. Particularly in the case of bacterial blood poisoning (sepsis), in which the heart valves are already affected, the inflammation often spreads to the heart muscle. Typical pathogens here are so-called staphylococci. Another group of bacteria, the streptococci, also sometimes cause myocarditis. They include, for example, the pathogens of scarlet fever or tonsillitis.
Another bacterial cause of myocarditis is diphtheria. Rarely, Lyme disease is to blame for an inflamed heart muscle. The pathogen, the bacterium Borrelia burgdorferi, is usually transmitted by ticks through their bite.
Other rare causative agents of myocarditis include parasites such as fox tapeworm or single-celled organisms such as the causative agents of toxoplasmosis or Chagas disease.
Non-infectious myocarditis.
In noninfectious myocarditis, no pathogens are the trigger. Instead, the cause is, for example, a dysregulation of the immune system. In this case, the immune system is directed against the body’s own structures, resulting in so-called autoimmune diseases. These include, for example, inflammation of the vessels or connective tissue and rheumatic diseases. Such autoimmune diseases sometimes also lead to inflammation of the heart muscle (autoimmune myocarditis).
Another cause of non-infectious myocarditis is radiation to the chest as part of radiotherapy for various cancers (such as lung cancer).
If no triggers for the myocarditis can be found, the physician also speaks of so-called idiopathic Fiedler myocarditis(giant cell myocarditis), for example, depending on the tissue changes. In this form of myocarditis, known as lymphocytic, lymphocytes (special white blood cells) migrate, causing parts of them to die (necrosis).
Risks of myocarditis
Myocarditis poses serious risks – especially if the affected person does not take sufficient care of himself or has a pre-damaged heart. This is because myocarditis more often causes severe cardiac arrhythmias.
In about one in six patients, myocarditis triggers remodeling processes in the heart that ultimately lead to chronic heart failure. The damaged heart muscle cells are then remodeled into scar tissue (fibrosis) and the heart cavities (ventricles, atria) dilate.
Physicians refer to this as dilated cardiomyopathy. The walls of the pathologically enlarged heart muscle are, in a sense, “worn out” and no longer contract powerfully. This means that a permanent cardiac insufficiency has developed. In severe cases, the pumping capacity of the heart then collapses completely. In the worst case, sudden cardiac death is the result.
How can myocarditis be diagnosed?
If you suspect cardiomyositis, your family doctor or a specialist in cardiology is the right person to contact. If necessary, the doctor will refer you to a hospital for further tests.
Doctor-patient consultation
Physical examination
This is followed by a thorough physical examination. Among other things, the doctor listens to your heart and lungs with a stethoscope, taps your chest and measures your pulse and blood pressure. He also looks to see if you show signs of incipient heart failure. These include water retention (edema) in your lower legs, for example.
ECG (electrocardiography)
Another important examination is measuring the electrical activity of the heart muscle (electrocardiography, ECG). This allows changes in the heart’s activity to be detected, as they occur in cardiomyopathy. Accelerated heartbeat (palpitations) and additional beats (extra systoles) are typical. Cardiac arrhythmias are also possible. Since the abnormalities are usually temporary, a long-term measurement of heart activity (long-term ECG) is advisable – in addition to the common short-term resting ECG.
Heart ultrasound
Blood examination
Inflammation values in the blood (CRP, ESR, leukocytes) show whether there is inflammation in the body. The physician also determines cardiac enzymes such as troponin-T or creatine kinase. These are released by heart muscle cells in the event of damage (e.g. as a result of myocarditis) and are then detectable in elevated quantities in the blood.
If antibodies against certain viruses or bacteria are found in the blood, this indicates a corresponding infection. If the myocarditis is the result of an autoimmune reaction, corresponding autoantibodies (antibodies against the body’s own structures) can be detected.
X-ray
Signs of myocarditis-related heart failure can be detected on an x-ray of the chest (chest x-ray). The heart is then enlarged. In addition, a back-up of fluid into the lungs, caused by the weak pumping action of the heart, is visible.
Magnetic resonance imaging (MRI)
Tissue removal by means of cardiac catheter
Sometimes, in the case of myocarditis, the cardiologist also performs an examination by means of a cardiac catheter. This involves taking a small tissue sample of the heart muscle (myocardial biopsy) and having it examined in the laboratory for inflammatory cells and pathogens.
There is no self-test for myocarditis. If you are unsure because of existing symptoms, talk to your treating physician.
What is the prognosis for myocarditis?
Myocarditis affects people of all ages, including young, heart-healthy people. If patients consistently take physical care of themselves, the course of the disease and prognosis are usually good. Overall, myocarditis heals in more than 80 percent of cases without leaving permanent damage. This is particularly true in the case of viral myocarditis. In some patients, harmless extra beats of the heart can subsequently be found in an ECG examination.
Infectious myocarditis develops over three phases, but these are not necessarily present in every affected person:
- Acute phase (pathogens invade the tissue and an initial immune response occurs with the release of certain signaling substances such as cytokines; duration: three to four days)
- Subacute phase (activation of natural killer cells in the blood that kill the viruses; repair processes begin at the same time; duration: up to four weeks)
- Chronic phase (viruses finally killed, repair and remodeling processes – scarring sometimes leads to functional disorders of the heart muscle; sometimes the inflammatory reaction persists; duration: several weeks to persistent)
Chronic myocarditis
Even minor exertion (such as climbing stairs) triggers shortness of breath (dyspnea) in those affected. Heart failure usually requires long-term treatment with medication. With appropriate therapy, however, the prognosis is good for most patients.
Duration of myocarditis
In individual cases, the duration of the disease depends on the extent of the inflammation and the patient’s general health.
It is also very difficult to say when a heart muscle inflammation has really healed completely. Even if a patient feels completely healthy again after overcoming myocarditis, he should continue to take it easy for a few weeks and avoid physical exertion. This is the only way to prevent serious late effects (such as heart failure).
Preventing myocarditis
For example, vaccination against diphtheria is advisable. This bacterial infectious disease poses other dangers besides the risk of myocarditis, such as severe pneumonia. Vaccination in childhood is usually given together with those against tetanus (lockjaw) and polio (polio).
It is also very important to properly cure flu-like infections. With any fever, it is advisable to avoid physical exertion as much as possible. The same applies even to a cold that seems harmless. If you “carry over” such an infection, the pathogens (viruses or bacteria) easily spread to the heart.
People who have already had myocarditis are particularly at risk of contracting it again (recurrence). To these people, doctors recommend being appropriately cautious. Above all, the combination of physical exertion, stress and alcohol should be avoided.
