MDC3 Practice Test

A systolic crescendo-decrescendo murmur is the tells-tale sound of flow obstruction across a semilunar valve during systole, most characteristically pointing to aortic stenosis. This murmur peaks as the LV pushes blood through the narrowed aortic valve and then eases as ejection wanes, giving the distinctive shape; it’s typically best heard at the right upper sternal border and may radiate toward the carotids. In contrast, mitral stenosis produces a diastolic murmur with an opening snap, while aortic and pulmonary regurgitation are diastolic lesions. Pulmonary stenosis can also cause a systolic murmur, but it’s usually heard best at the left upper sternal border and is less common in adults. The key takeaway is that a systolic ejection murmur with crescendo-decrescendo timing and carotid radiation most strongly indicates aortic stenosis.