Cardiology · Valvular Heart Disease
The facts most likely to be tested
The classic auscultatory finding of mitral valve prolapse is a mid-systolic click followed by a late systolic murmur.
Maneuvers that decrease left ventricular volume, such as Valsalva maneuver or standing, cause the click to occur earlier in systole.
Maneuvers that increase left ventricular volume, such as squatting or handgrip, cause the click to occur later in systole.
Mitral valve prolapse is most commonly associated with myxomatous degeneration of the valve leaflets.
Patients with Marfan syndrome or Ehlers-Danlos syndrome have a significantly increased risk of developing mitral valve prolapse due to connective tissue abnormalities.
Most patients with asymptomatic mitral valve prolapse require no specific treatment other than reassurance and routine clinical follow-up.
Beta-blockers are the first-line therapy for patients who present with palpitations or atypical chest pain associated with mitral valve prolapse.
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A 24-year-old female presents for a routine physical examination. She reports occasional episodes of palpitations but denies syncope, dyspnea, or chest pain. On cardiac auscultation, a mid-systolic click is heard at the apex, followed by a late systolic murmur. When the patient is asked to squat, the click moves later in systole and the murmur intensity decreases. She has a tall, thin habitus with long, slender fingers.
What is the most likely underlying etiology of this patient's condition?
Myxomatous degeneration of the mitral valve
The patient's physical exam findings are classic for mitral valve prolapse, which is frequently caused by myxomatous degeneration, especially in patients with connective tissue disorders like Marfan syndrome.
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Etiology / Epidemiology
Common in young women and patients with Marfan syndrome or Ehlers-Danlos syndrome.
Clinical Manifestations
Classic mid-systolic click followed by a late systolic murmur that moves earlier with Valsalva.
Diagnosis
Transthoracic echocardiogram is the gold standard; confirms leaflet displacement >2mm above the annulus.
Treatment
Beta-blockers for symptomatic palpitations; avoid stimulants and maintain hydration.
Prognosis
Generally benign; monitor for mitral regurgitation and rare risk of infective endocarditis.
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Epidemiology & Etiology
Most common valvular abnormality in the US, often idiopathic or associated with connective tissue disorders. Frequently seen in Marfan syndrome, Ehlers-Danlos, and osteogenesis imperfecta. Often presents in young, thin females.
Pertinent Anatomy
Characterized by myxomatous degeneration of the mitral valve leaflets. The leaflets become redundant and prolapse into the left atrium during ventricular systole.
Pathophysiology
Myxomatous degeneration leads to chordae tendineae elongation and leaflet thickening. This structural failure causes the valve to 'snap' into the atrium, creating the mid-systolic click. Progressive stretching can lead to secondary mitral regurgitation.
Clinical Manifestations
Patients are often asymptomatic, but may report atypical chest pain or palpitations. The mid-systolic click is the hallmark finding. Maneuvers that decrease preload, such as Valsalva or standing, cause the click to occur earlier in systole. Red flags include syncope or sudden cardiac death, though these are rare.
Diagnosis
Transthoracic echocardiogram is the diagnostic test of choice. It confirms leaflet displacement >2mm above the mitral annulus. Transesophageal echocardiogram is reserved for cases where TTE is nondiagnostic or surgical planning is required.
Treatment
Asymptomatic patients require no specific therapy. Beta-blockers are the first-line treatment for symptomatic palpitations or autonomic dysfunction. Avoid stimulants like caffeine and alcohol. Surgical repair is indicated only if severe mitral regurgitation develops.
Prognosis
Prognosis is excellent for the majority. Long-term monitoring focuses on the development of mitral regurgitation and heart failure. Prophylaxis for infective endocarditis is no longer routinely recommended.
Differential Diagnosis
Hypertrophic Cardiomyopathy: murmur increases with Valsalva, no click
Mitral Regurgitation: holosystolic murmur, no click
Atrial Septal Defect: fixed split S2, no click
Tricuspid Valve Prolapse: right-sided heart findings
Panic Disorder: mimics palpitations without valvular findings