Myocarditis, also known as inflammatory cardiomyopathy, is an acquired cardiomyopathy due to inflammation of the heart muscle. Symptoms can include shortness of breath, chest pain, decreased ability to exercise, and an irregular heartbeat. The duration of problems can vary from hours to months. Complications may include heart failure due to dilated cardiomyopathy or cardiac arrest.Myocarditis is most often due to a viral infection. Other causes include bacterial infections, certain medications, toxins and autoimmune disorders. A diagnosis may be supported by an electrocardiogram (ECG), increased troponin, heart MRI, and occasionally a heart biopsy. An ultrasound of the heart is important to rule out other potential causes such as heart valve problems.Treatment depends on both the severity and the cause. Medications such as ACE inhibitors, beta blockers, and diuretics are often used. A period of no exercise is typically recommended during recovery. Corticosteroids or intravenous immunoglobulin (IVIG) may be useful in certain cases. In severe cases an implantable cardiac defibrillator or heart transplant may be recommended.In 2013, about 1.5 million cases of acute myocarditis occurred. While people of all ages are affected, the young are most often affected. It is slightly more common in males than females. Most cases are mild. In 2015 cardiomyopathy, including myocarditis, resulted in 354,000 deaths up from 294,000 in 1990. The initial descriptions of the condition are from the mid-1800s.
More specifically, fulminant myocarditis is characterized by a distinct, rapid onset of severe heart failure symptoms, such as shortness of breath and chest pain, that develop over the course of hours to days. Additionally, treatment requires the use of medications or mechanical devices to improve heart function.Acute non-fulminant myocarditis has a less distinct onset in contrast to fulminant myocarditis, and evolves over days to months. While the symptoms of acute myocarditis overlap with those of fulminant myocarditis, they do not typically occur at rest, and treatment does not require the use of mechanical circulatory support. Causes
While many causes of myocarditis are known, there are many cases in which a causative agent cannot be identified. In Europe and North America, viruses are common culprits. Worldwide, however, the most common cause is Chagas disease, an illness endemic to Central and South America that results from infection with the protozoan Trypanosoma cruzi. Overall, myocarditis can be caused by infections, immune conditions, toxins, drug reactions, and physical injuries to the heart. These different etiologies are detailed below. Myocarditis is a rare adverse side effect from mRNA COVID-19 vaccines. Infections
The most common causes of myocarditis are infectious organisms. Viral infections are the most common cause in developed countries, with a majority of cases being caused by those with single-stranded RNA genetic information such as Coxsackie viruses (especially Coxsackie B3 and B5). Globally, Chagas disease is the leading cause of myocarditis, which results from infection with the protozoan Trypanosoma cruzi.