Myocarditis

– Olga g.goryacheva.

estimated to affect thousands of adults and children around the

world each year.  3.1 million cases of myocarditis were diagnosed in 2017 (statistics posted in Lancet, November 2018). Because many individuals – and even physicians – are unfamiliar with this condition, the Myocarditis Foundation was established in 2005 to provide a trusted resource for those affected by myocarditis. Here, we’ll review the disease’s causes, symptoms, treatment and more to answer your most pressing questions

inflammation of the heart muscle. This inflammation enlarges and weakens

the heart, creates scar tissue and forces it to work harder to circulate blood and oxygen throughout the body.
myocarditis can affect anyone, including young adults, children and infants. In fact, it most often affects otherwise healthy, young, athletic types with the high-risk population being those of ages from puberty through their early 30’s, affecting males twice as often as females. Myocarditis is the 3rd leading cause of Sudden Death in children and young adults.

are a leading cause of myocarditis. Inflammation occurs during the

course of infection, putting stress on the heart that remains even after the infection is resolved. Cancer, bacterial infections and other contagious diseases can also cause myocarditis, as can exposure to environmental toxins ranging from metal poisons to spider and snake venom.
myocarditis is a result of the body’s immune reaction to the initial heart damage
A significantly smaller group of individuals with autoimmune conditions, may develop giant cell myocarditis. This variation of the disease often results in rapid deterioration but may still respond successfully to treatment, especially when diagnosed early. Currently there are no known lifestyle choices or medical treatments that can prevent myocarditis.
Myocarditis can also accompany systemic inflammatory disorders such as lupus or Kawasaki disease
Myocarditis is not inherited. There are no known genes associated with human myocarditis.

Myocarditis in a mouse heart. Cardiac inflammation stains purple.

widespread lymphocytic infiltrate, myocyte necrosis, numerous eosinophils, and several giant

cells (hematoxylin and eosin). Images provided courtesy of Dr. Wendy Gunther.

GIANT CELL MYOCARDITIS HISTOLOGY..

to the diagnosis and treatment of myocarditis is its lack

of specific symptoms. In many cases, individuals experience no symptoms at all. When they are present, symptoms may point to the viral infection itself or suggest other cardiac problems such as a heart attack. Common symptoms can include but are not limited to:
Shortness of breath, especially after exercise or when lying down
A sensation of tightness or squeezing in the chest that is present with rest and with exertion is common.
Not infrequently chest pain is improved with leaning forward and worse with lying back when the inflammation affects the outer lining of the heart or pericardium as well as the heart muscle.
PTO

loss of consciousness
In a majority of cases, the symptoms of

myocarditis are preceded a few days to weeks by a flu-like illness.
If any of these symptoms are detected, it’s important to speak to your doctor right away.

the ages of 20 and 40 years. Children seem to

have a more severe presentation than adults.
Men are generally more frequently affected than women, possibly due to effects of testosterone on the immune reaction to infection.
The relative frequency of more common age related cardiovascular diseases such as coronary artery disease may lead to under diagnosis in the elderly.
Certain forms of myocarditis, such as cardiac sarcoidosis, are more common in black than white persons in the US.
 In 2010, approximately 400,000 people died of heart muscle disease (cardiomyopathy that includes myocarditis) world wide, including 160,000 women and 240,000 men.

symptoms. For example chest pain and shortness of breath with

activity can result from many forms of heart disease and non-cardiac causes. Because the diagnostic tests for cardiac inflammation, magnetic resonance imaging or heart biopsy, are not widely available, the diagnosis is often overlooked.
In people who have autoimmune disorders, myocarditis may result from an autoimmune reaction against heart tissues and not a viral infection. In this setting, myocarditis is a part of a more widespread process that may require treatment with medication to suppress the immune system.
  Myocarditis can also exacerbate the cardiac damage from other rare heart diseases such as amyloidosis.

no symptoms and are not diagnosed. However, when a person

develops symptoms, common tests for myocarditis include the following:
An Electrocardiogram Electrical activity of your heart is detected by electrodes taped to your skin. This activity is recorded as waves that represent the electrical forces in the different parts of the heart.
A Chest X-Ray A chest X-ray produces an image on film that outlines your heart, lungs and other structures in your chest. From a chest X-ray, your physician learns information such as the size and shape of your heart.

are used to make an image of your heart or

analyze blood flow. The sound waves are sent into your body from a transducer, a small plastic device. The sound waves are reflected back from internal structures, returning to the transducer and producing images of the heart and its structures.
Less frequently, a cardiac magnetic resonance imaging (MRI) scan may be done to diagnose myocarditis. An MRI creates images using a magnetic field and radio waves.
Occasionally, a heart biopsy is required to confirm the diagnosis

primarily for detecting rejection of a donor heart following heart transplantation. It is also used

as a diagnostic tool in some heart diseases.

Algorithm for evaluation of suspected myocarditis in the setting of unexplained acute cardiomyopathy.
COR(CLASS OF RECOMMENDATION), LOE(LEVEL OF EVIDENCE), MRI(MAGNETIC RESOURCE IMAGING) *Usually a DCM.
Fulminant myocarditis may have normal and diastolic diameter with mildely thickened wall. Exclude ischemic, hemodynamic(valvular, hypertensive), metabolic and toxic causes of cardiomyopathy as indicated clinically.

pump function should be treated according to the current national

society guidelines for “systolic” heart failure. Drugs that block the immune system are generally not indicated for the management of the most common forms of myocarditis in adults. However, in specific forms of myocarditis such as giant cell myocarditis, cardiac sarcoidosis or eosinophilic myocarditis, medications that modify the immune response should be considered. These specific forms of myocarditis are diagnosed by heart biopsy. Sports participation during acute viral myocarditis may cause sudden death. Thus high levels of physical activity following the diagnosis of myocarditis should be avoided for at least 3 to 6 months.  Non-steroidal anti-inflammatory drugs such as ibuprofen should be avoided due to a risk of increased inflammation.
 Some patients with severe myocarditis develop low blood pressure despite optimal medical care. These patients may require a temporary heart pump (a kind of mechanical circulatory support device) to survive the acute injury. Some of these patients with myocarditis can be bridged to recovery and have the pump removed. The survival after heart transplantation for adult patients with myocarditis is similar to that for other causes of cardiac failure. Patients with severe myocarditis should be seen by cardiologists with expertise in heart failure and heart rhythm disorder management.

circulatory support and transplantation
Antiviral treatment
Immunosuppressive treatment
Intravenous immunoglobulin
Antiarrhythmic treatment
Physical activity

free from the effects of myocarditis. For others, however, ongoing

cardiovascular medication or even a heart transplant may be needed. Overall, myocarditis which can cause dilated cardiomyopathy, are thought to account for up to 45 percent of heart transplants in the U.S. today.
Healthy lifestyle changes can also support proper heart function. Your doctor may recommend that you reduce sodium in your diet, avoid alcohol, limit fluid intake and quit smoking. It’s also generally advised that you avoid competitive sports and other rigorous exercise for a period after diagnosis, to be determined by the cardiologist. And while it’s possible for the disease to come back, more-so in giant cell myocarditis, it is extremely rare.

can lead to a chronically enlarged heart (called dilated cardiomyopathy).

There is no known way to prevent recurrence of myocarditis. However, the risk of recurrence is low (probably about 10 to 15 percent).

medical treatments are known to prevent viral myocarditis.
Because myocarditis is

rare, information is limited regarding its causes and effective treatments. Myocarditis is not believed to be inherited. No genes are known to predispose people to myocarditis.