The loud background noise in the emergency department makes the accurate auscultation of subtle murmurs difficult. Despite this, the emergency physician may suspect undiagnosed valvular dysfunction on incidental cardiac auscultation. The ECG and chest radiograph may be of help, but neither is confirmatory. The suspected diagnosis should be confirmed by echocardiography and/or consultation with a cardiologist. Transesophageal echocardiography yields a more complete analysis of valvular dysfunction, especially for the mitral valve. However, transthoracic echocardiography is generally performed first. 7 The urgency for an accurate diagnosis and appropriate referral depends on the severity of symptoms and the suspected diagnosis. For example, a patient presenting with syncope and auscultatory findings of aortic stenosis should be admitted to the hospital for observation and further evaluation.
DIAGNOSING A NEWLY DISCOVERED MURMUR The first step in diagnosing a newly discovered murmur is to consider it in the context of the patient's medical condition. Patients with normal cardiac anatomy may have murmurs associated with anemia, thyrotoxicosis, sepsis, fever, renal failure with volume overload, pregnancy, and other clinical conditions. A diastolic murmur or a new murmur associated with symptoms at rest should always be considered abnormal and warrants referral for a workup and possible echocardiographic study and admission. Figure,„50.-.1. presents an algorithm for the clinical assessment of a newly discovered systolic murmur. The algorithm, based on the work of Etchells and colleagues,8 presents a step-by-step method of assessment to uncover an abnormal murmur. Each murmur category lists characteristics or maneuvers that have been shown to predict the presence of the named abnormal murmurs. The studies referred to by Etchells and colleagues have used cardiologists as examiners, and these issues have not been tested in the emergency department setting. However, the algorithm can be expected to prompt the clinician to perform the appropriate examinations and maneuvers to help uncover an abnormal murmur. Whenever the clinician is uncertain of the diagnosis of a newly discovered murmur, referral should be made to a cardiologist or back to the primary care physician for an appropriate workup.
A truly innocent (physiologic) murmur is associated with no abnormal symptoms or signs. The soft systolic ejection murmur begins after S and ends before S2, and the heart sounds are completely normal. The review of systems should elicit no symptoms compatible with cardiovascular disease, and findings upon complete physical examination are normal with the exception of the flow murmur.
Acute mitral and aortic incompetence are important and urgent diagnoses. Due to the severity of symptoms, it is unlikely that such a patient would go unnoticed in the emergency department, but the patient may be admitted with the murmur unrecognized. Acute mitral or aortic incompetence should always be suspected in patients with acute pulmonary edema, especially when the heart is smaller than expected on the chest radiograph or when the patient does not respond to conventional therapy. When aortic dissection is suspected as the cause of acute aortic incompetence and the patient is sufficiently stable, transesophageal echocardiography or computed tomographic (CT) scanning of the chest is useful. Angiography may still be required after CT scanning.
In infants, a newly diagnosed murmur demands the consideration of congenital heart disease, such as ventricular septal defect, atrial septal defect, and pulmonic stenosis in association with tetralogy of Fallot. See Chapter,115, "Heart Disease," for a more detailed discussion of congenital heart disease in children.
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