Myocarditis is an inflammatory disease of the heart muscle (myocardium). Mostcases of myocarditis in the United States originate from a virus, and the disease may remain undiagnosed by doctors due to lack of initial symptoms. Thedisease may also present itself as an acute, catastrophic illness that requires immediate treatment. Although the inflammation or degeneration of the heart muscle that myocarditis causes may be fatal, this disease often goes undetected. It may also disguise itself as ischemic, valvular, or hypertensive heart disease. Myocarditis is a rare but serious condition that affects both males and females of any age.
An inflammation of the heart muscle may occur as an isolated disorder or be the dominant feature of a systemic disease (one that affects the whole body).
While there are several contributing factors that may lead to myocarditis, the primary cause is viral. Myocarditis usually results from the Coxsackie B virus, and may also result from measles, influenza, chicken pox, hepatitis virus, or the adenovirus in children.
If an acute onset of severe myocarditis occurs, a patient may display the following symptoms: rhythm disturbances of the heart; rapid heartbeat (ventricular tachycardia); left or right ventricular enlargement; shortness of breath (dyspnea); pulmonary edema (the accumulation of fluid in the lungs); and swollen legs.
Additional causes of myocarditis include: bacterial infections, such as tetanus, gonorrhea, or tuberculosis; parasite infections; rheumatic fever; surgeryon the heart; radiation therapy for cancer and certain medications.
As of 1996, research has shown that illegal drugs and toxic substances may also produce acute or chronic injury to the myocardium. These studies also indicate an increase in the incidence of myocarditis from the use of cocaine. Further studies conducted in 1996 indicate that malnutrition encourages the Coxsackie B virus to flourish, leading to the potential development of myocarditis. Human immunodeficiency virus (HIV) is also now recognized as a cause of myocarditis, although its prevalence is not known.
The best way to diagnose myocarditis may be through a person's observation ofhis or her own symptoms, followed by a thorough medical history and physicalexam conducted by a doctor. Tests usually include laboratory blood studies and echocardiography. An electrocardiogram (ECG) is also routinely used due toits ability to detect a mild case of the disease. Cardiac catheterization and angiography are additional diagnostic tests used to determine the presenceof myocarditis, or to rule out other possible heart diseases that may lead toheart failure.
Another measure used to diagnosis myocarditis is the endomyocardial biopsy procedure. This invasive catheterization procedure examines a piece of the endocardium (the lining membrane of the inner surface of the heart) to verify thepresence of the disease.
While myocarditis is a serious condition, there is no medical treatment necessary if it results from a general viral infection. The only steps to recoveryinclude rest and avoidance of physical exertion. Adequate rest becomes moreimportant to recovery if the case or myocarditis is severe with signs of dilated cardiomyopathy (disease of the heart muscles). In this case, medical treatment for congestive heart failure may include medications such as angiotensin converting enzyme (ACE) inhibitors, diuretics to reduce fluid retention, digitalis to stimulate a stronger heartbeat, and/or low-dose beta-blockers.
If myocarditis is caused by a bacterial infection, the disease is treated with antibiotics. If severe rhythm disturbances are involved, cardiac assist devices, an "artificial heart," or heart transplantation may be the onlyoption for complete recovery.
The outlook for a diagnosed case of myocarditis caused by a viral infection is excellent, with many cases healing themselves spontaneously. Because this disease ranges from mild to severe, the disease resolution may vary from complete healing (with or without significant scarring), to severe congestive heart failure leading to death or requiring a heart transplant.
Inflammation of the myocardium may also cause acute pericarditis (inflammation of the outer lining of the heart). Due to the potential effects of the disease, including sudden death, it is imperative that proper medical attention be obtained.