Myocarditis is an inflammatory process involving the myocardium. Myocarditis can cause heart dilation, thrombi on the heart wall (mural thrombi), infiltration of circulating blood cells around the coronary vessels and between the muscle fibers, and degeneration of the muscle fibers themselves. The incidence of myocarditis is estimated to be 1 to 10 cases per 100,000 persons. The rate may be higher because the variety of clinical presentations may cause underreporting (Tang, 2001). Mortality varies with the severity of symptoms. Most patients with mild symptoms recover com-pletely. Other patients may develop cardiomyopathy and heart failure. Patients with symptomatic heart failure and an ejection fraction of less than 45% had a 1-year mortality rate of 20% and a 4-year mortality rate of 56% (Tang, 2001).
Myocarditis usually results from a viral, bacterial, mycotic, para-sitic, protozoal, or spirochetal infection. It also may occur in pa-tients after acute systemic infections such as rheumatic fever, in those receiving immunosuppressive therapy, or in those with in-fective endocarditis. Myocarditis may result from an allergic re-action to pharmacologic agents used in the treatment of other diseases. It may begin in one small area and then spread through-out the myocardium. The degree of myocardial involvement de-termines the degree of hemodynamic effect and resulting signs and symptoms. It is theorized that dilated cardiomyopathy is a la-tent manifestation of myocarditis.
The symptoms of acute myocarditis depend on the type of infec-tion, the degree of myocardial damage, and the capacity of the myocardium to recover. The patient may be asymptomatic, andthe infection resolves on its own. The patient may develop mild to moderate symptoms and seek medical attention. The patient may also sustain sudden cardiac death or quickly develop severe congestive heart failure. The patient with mild to moderate symptoms often complains of fatigue and dyspnea, palpitations, and occasional discomfort in the chest and upper abdomen.
Assessment of the patient may reveal no abnormalities; as a result, the entire illness goes unrecognized. The patient may complain of chest pain (with a subsequent cardiac catheterization demon-strating normal coronary arteries). The patient without any ab-normal heart structure (at least initially) may suddenly develop dysrhythmias. If the patient has developed structural abnormali-ties (eg, systolic dysfunction), the clinical assessment may disclose cardiac enlargement, faint heart sounds, gallop rhythm, and a sys-tolic murmur.
Prevention of infectious diseases by means of appropriate immu-nizations (eg, influenza, hepatitis) and early treatment appears to be important in decreasing the incidence of myocarditis (Braunwald et al., 2001).
The patient receives specific treatment for the underlying cause if it is known (eg, penicillin for hemolytic streptococci) and is placed on bed rest to decrease the cardiac workload. Bed rest also helps to decrease myocardial damage and the complications of myocarditis. Activities, especially sports in young patients with myocarditis, should be limited for a 6-month period or at least until heart size and function have returned to normal. Physical activity is increased slowly, and the patient is instructed to report any symptoms that occur with increasing activity, such as a rapidly beating heart. The use of corticosteroids in treating myo-carditis remains controversial (Braunwald et al., 2001). Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen are not to be used during the acute phase or if the pa-tient develops heart failure, because these medications can cause further myocardial damage. If the patient develops heart failure, management is essentially the same as for all causes of heart failure .
The nurse assesses the patient’s temperature to determine whether the disease is subsiding. The cardiovascular assessment focuses on signs and symptoms of heart failure and dysrhythmia. The patient experiencing dysrhythmias should receive continuous cardiac monitoring with personnel and equipment readily available to treat life-threatening dysrhythmias.Elastic compression stockings and passive and active exercises should be used, because embolization from venous thrombosis and mural thrombi can occur.
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