There is little that the emergency physician can do to change the structural abnormality of the diseased cardiac valve. The exception to this rule is acute mitral incompetence due to myocardial infarction. The infusion of thrombolytic therapy may reestablish blood flow to the papillary muscle, with restoration of function. 9 The alternative to thrombolytic therapy is coronary angioplasty.10 The majority of treatments are directed toward symptomatic relief of the manifestations of valvular disease. However, there are certain medical treatments that can reduce the consequences of the mechanical defect. The regurgitation of aortic and mitral incompetence may be lessened by reducing afterload. When the cause of mitral incompetence is myocardial ischemia, regurgitation can be lessened by treatment with nitrates.
Pulmonary edema should be treated with oxygen, intubation for failing respiratory effort, diuretics, and nitrates if tolerated. Patients with aortic stenosis usually have normal-to-low blood pressure and do not tolerate afterload reducers. In contrast, patients with mitral incompetence or aortic incompetence can benefit from intravenous nitroprusside or nitroglycerin even with normal blood pressures. 11 Reducing afterload helps to reduce regurgitation and relieve pulmonary edema. Tachycardia reduces the regurgitant volume by reducing the time during the cardiac cycle during which backflow may occur. Therefore, artificially lowering the pulse with a b-blocking agent may worsen symptoms.
The hypertension associated with aortic dissection should be controlled with intravenous nitroprusside and b blockade. Labetalol has been used with success in this setting. Patients with valvular heart disease and acute pulmonary edema should be considered for Swan-Ganz catheter insertion. The presence of valvular disease, especially stenosis, may complicate the procedure of catheter insertion. In patients who do not respond to medical management, intraaortic balloon counterpulsation should be considered. However, this is contraindicated in wide-open aortic regurgitation.
Rapid atrial fibrillation, which may precipitate symptoms in patients with silent valvular disease, should be rate-controlled with intravenous diltiazem or digoxin. Intravenous propranolol or verapamil may be considered, but their negative inotropic action may cause more problems. Emergency cardioversion may be needed in severely compromised patients, but dysrhythmia recurrence is common. The most common cause of the dysrhythmia in valvular heart disease, a dilated atrium, remains unchanged by cardioversion. The danger of embolization is greater in patients with atrial fibrillation.
Hemoptysis associated with valvular heart disease most frequently accompanies pulmonary edema and is frothy pink. This form of hemoptysis does not in and of itself require treatment. However, if pulmonary hypertension is present, gross hemoptysis may occur from the rupture of distended bronchial veins. Mitral stenosis is the most frequent valvular heart disease associated with hemoptysis, which can be severe enough to require blood transfusion and emergency surgery.
In the event of embolization, anticoagulation should be undertaken with intravenous heparin as long as there is no evidence of central nervous system bleeding. Anticoagulation is especially needed in the setting of atrial fibrillation.
Emergency surgery should be considered in all cases of acute symptomatic valvular disease.12 Because stenotic lesions are slowly progressive, emergency surgery is rarely needed for stenotic defects. However, a patient with new onset of syncope in association with aortic stenosis should be considered for urgent repair. The need for emergency surgery most commonly accompanies acute regurgitant lesions of the mitral or aortic valves. Patients are acutely ill and present considerable surgical risks. The urgency of these two acute regurgitant lesions leaves little time for intubation, intravenous afterload reducers, echocardiography, and assembling the surgical team for emergency valve replacement.
Patients with acute fevers should be suspected of having infective endocarditis. The evaluation and management of endocarditis are discussed below, under
"Infective Endocarditis." Antibiotic prophylaxis for infective endocarditis is recommended during procedures that may produce bacteremia in patients at risk for developing endocarditis, and the American Heart Association guidelines, which were revised in 1997, should be followed. 13 Patients considered at risk include those with a prosthetic heart valve, a history of endocarditis, rheumatic heart disease, acquired and congenital valvular disease, idiopathic hypertrophic subaortic stenosis, mitral valve prolapse with a murmur, or surgically constructed pulmonary shunts or conduits. The common procedures performed by emergency physicians that require prophylaxis are listed in T.§ble 5.0.-1. Endotracheal intubation does not require antibiotic prophylaxis. When a febrile patient is being evaluated for urinary tract infection, emergency physicians should consider the need for prophylaxis before using a catheter to obtain a urine specimen. However, recent data from an epidemiologic study suggest that medical and dental procedures cause only 5 percent of endocarditis cases and prophylaxis does not prevent all cases. 13
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