Review Question - QID 212606

This patient with palpitations, exertional dyspnea, a mid-systolic click, and a late systolic murmur most likely has mitral valve prolapse, which is associated with increased valvular dermatan sulfate.

Mitral valve prolapse is caused by redundant mitral valve tissue, which results in bulging of one or both leaflets into the left atrium during systole. This excess tissue may be the result of increased dermatan sulfate production or myxomatous degeneration. This disease is usually seen in young women as an isolated abnormality, but it can also be associated with Marfan syndrome and Ehlers-Danlos syndrome. Cardiac auscultation in this disorder will demonstrate a mid-systolic click due to sudden tensing of the chordae tendineae. A late systolic murmur may also follow the click if regurgitation is present.

Incorrect Answers:
Answer 1: Bicuspid aortic valve is associated with aortic stenosis; however, this disease would present with midsystolic murmur best heard in the right second intercostal space.

Answer 3: Infection with Streptococcus pyogenes is associated with mitral valve stenosis and regurgitation; however, this patient has no other signs of rheumatic fever and was treated with antibiotics.

Answer 4: Intravenous drug abuse is associated with tricuspid valve defects; however, this would not present with a mid-systolic click.

Answer 5: Mutation in cardiac contractile proteins is associated with hypertrophic cardiomyopathy; however, this disease would not present with a mid-systolic click.

Bullet Summary:
Mitral valve prolapse may be the result of increased valvular dermatan sulfate production.