Final answer:
A subauricular systolic bruit in a young patient with severe hypertrophic cardiomyopathy indicates the presence of turbulent blood flow caused by the thickened heart muscle, suggesting the patient requires further cardiac evaluation.
Step-by-step explanation:
In a young patient with severe hypertrophic cardiomyopathy (HCM), a subauricular systolic bruit is often highly indicative of this condition. HCM is a pathological enlargement of the heart where the heart muscle becomes abnormally thick. This thickening can make it harder for the heart to pump blood. When auscultating the heart with a stethoscope, the typical heart sounds that are heard include the "lub" and "dub" of the atrioventricular and semilunar valves closing, respectively. However, in patients with HCM, additional sounds such as murmurs or bruits may be detectable, which are caused by the turbulent blood flow across the abnormal cardiac structures. The presence of a subauricular systolic bruit would warrant further cardiac evaluation, typically with echocardiography, to assess the extent of hypertrophy and any potential obstruction of blood flow out of the heart.