An 18 year-old student visits her physician for a routine physical examination. She has no complaints. Physical examination is unremarkable except for a midsystolic click followed by a late systolic murmur heard at the lower left sternal border and apex. The murmur duration increases in standing and shortens with squatting. Electrocardiogram (ECG) shows no abnormalities. Which of the following is the most likely diagnosis of this condition? A- Mitral stenosis B- Aortic stenosis C- Mitral valve prolapse D- Tricuspid regurgitation E- Dilated cardiomyopathy Answer
