This young patient with an opening snap after S2 followed by a low-pitched, rumbling murmur has signs characteristic of mitral stenosis (MS). The most common cause of MS worldwide is rheumatic heart disease, a sequela of untreated streptococcal pharyngitis.
Rheumatic heart disease leads to fusion of the mitral leaflet commissures, as well as thickened, fused, and shortened chordae tendinae. The opening snap heard in mitral stenosis is caused by a sudden halt in the movement of the mitral leaflets as they open, due to fused commissures. It is important to differentiate an opening snap from a split S2--the former is heard best at the apex, the latter at the base of the heart. The late diastolic rumble heard in MS is caused by turbulent blood flow through the stenotic valve.
Shipton and Wahba discuss the diagnosis and treatment of the major types of valvular heart disease. They note that MS primarily affects women; many cases are asymptomatic until pregnancy, when the heart is under increased strain. Another common presenting manifestation is atrial fibrillation, caused by left atrial enlargement due to the increased afterload placed on that chamber.
Dean et al. reported a retrospective study of 736 patients with MS who underwent percutaneous mitral valve commissurotomy. There was an 84% survival rate at 4 years; risk factors associated with mortality included age >70 and NYHA heart failure class IV status.
Video V shows an animation mitral stenosis with accompanying audio.
Illustration A shows a grossly stenotic mitral valve.
Illustration B shows phonocardiograms of the four major valvular disorders.
Illustration C shows a schematic representation of the cardiac catheterization findings in MS.
Answer 1: Bicuspid aortic valve is inherited in an autosomal dominant fashion; this condition can lead to aortic stenosis (AS) at a young age, characterized by a crescendo-decrescendo systolic murmur that radiates to the carotids and pulsus parvus et tardus.
Answer 2: A potential complication of Marfan syndrome is aortic root dilatation and resulting aortic regurgitation (AR), characterized by a decrescendo diastolic murmur, water hammer pulses, Quincke pulses, and other classic manifestations.
Answer 3: Mitral valve prolapse may progress to mitral regurgitation (MR), characterized by a pansystolic murmur heard best at the cardiac apex and radiating to the axilla.
Answer 5: Tricuspid regurgitation (TR) is a potential complication of carcinoid syndrome. The TR murmur is pansystolic, but unlike the MR murmur is best heard at the left lower sternal border.
Shipton B, Wahba H. Valvular heart disease: review and update. Am Fam Physician. 2001 Jun 1;63(11):2201-8. Review.
PMID:11417772 (Link to Abstract)
Dean LS, Mickel M, Bonan R, Holmes DR Jr, O'Neill WW, Palacios IF, Rahimtoola S, Slater JN, Davis K, Kennedy JW. Four-year follow-up of patients undergoing percutaneous balloon mitral commissurotomy. A report from the National Heart, Lung, and Blood Institute Balloon Valvuloplasty Registry. J Am Coll Cardiol. 1996 Nov 15;28(6):1452-7.
PMID:8917257 (Link to Abstract)
USMLE World Step 1 QBank Question #1517. Copyright © USMLEWorld, LLC 2012