USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

What heart condition is suspected when there is turbulent flow during ventricular systole into the left atrium?

1. Coarctation of the aorta

2. Patent ductus arteriosus

3. Aortic regurgitation

4. Mitral regurgitation

The correct answer is: Mitral regurgitation

Mitral regurgitation is the correct answer because this condition involves the failure of the mitral valve to close properly during ventricular systole, causing blood to flow back into the left atrium. This can result in a turbulent flow pattern during ventricular systole into the left atrium. Option A, Coarctation of the aorta, involves a narrowing of the aorta and would not necessarily cause turbulent flow into the left atrium. Option B, Patent ductus arteriosus, is an abnormal connection between the aorta and the pulmonary artery, and whilst this can cause turbulent flow, it is not specifically in line with the question which mentions the flow into the left atrium. Option C, Aortic regurgitation, involves the backflow of blood from the aorta into the left ventricle during diastole, not systole. This would not explain the turbulent flow during ventricular systole into the left atrium.