cardiovascular disorders
Mitral Stenosis
Key Points
Mitral stenosis is usually caused by rheumatic fever, although calcific degeneration is increasingly observed in older patients. Pulmonary hypertension and atrial fibrillation may develop. The risk of thromboembolism in patients with atrial fibrillation and mitral stenosis is very high and is treated with a vitamin K antagonist, not a direct-acting oral anticoagulant. Heart sounds include a loud first heart sound and an early diastolic opening snap followed by a low-pitched decrescendo-crescendo rumbling diastolic murmur, heard best at the apex at end-expiration when the patient is in the left lateral decubitus position; the murmur increases after a Valsalva maneuver, exercise, squatting, and isometric handgrip. Mildly symptomatic patients usually respond to diuretics and, if sinus tachycardia or atrial fibrillation is present, to beta-blockers or calcium channel blockers for rate control. Severely symptomatic patients and those with evidence of pulmonary hypertension require commissurotomy or valve replacement. 