Acute myocarditis

Myocarditis
Synonyms	Inflammatory cardiomyopathy

A microscope image of myocarditis at autopsy in a person with acute onset of heart failure
Specialty	Cardiology
Symptoms	Shortness of breath, chest pain, decreased ability to exercise, irregular heartbeat
Complications	Heart failure due to dilated cardiomyopathy, cardiac arrest
Duration	Hours to months
Causes	Usually viral infection, also bacterial infections, certain medications, toxins, autoimmune disorders
Diagnostic method	Electrocardiogram, blood troponin, heart MRI, heart biopsy
Treatment	Medications, implantable cardiac defibrillator, heart transplant
Medication	ACE inhibitors, beta blockers, diuretics, corticosteroids, intravenous immunoglobulin
Frequency	2.5 million with cardiomyopathy (2015)
Deaths	354,000 with cardiomyopathy (2015)
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Classification	· · ICD-10: I09.0, I51.4 ICD-9-CM: 391.2, 422, 429.0 MeSH: D009205 DiseasesDB: 8716
External resources	MedlinePlus: 000149 eMedicine: article/156330 article/890740 article/1612533 Patient UK: Myocarditis

Myocarditis, also known as inflammatory cardiomyopathy, is 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.