Valvular Disease
Objectives • To understand the pathophysiology • To learn how to examine the patient • To understand the principles of laboratory diagnosis • To learn the fundamentals for treatment
1. Mitral Stenosis
Etiology • Almost always the result of rheumatic fever • Less common causes – Congenital mitral stenosis – Systemic lupus erythematosus – Rheumatoid arthritis – Atrial myxoma – Bacterial endocarditis
Epidemiology • Rare in developed countries in patients <40 • Very common in developing countries, esp. South Asia, often at early age (<20) • 2/3 of all patients are female. • The onset of symptoms usu. between the 3rd and 4th decades
Pathology • Normal mitral valve area (MVA): 4-6 cm2 • Acute rheumatic fever • Immune-mediated inflammation of valves – the leaflets thickened – the commissures fused – thickening and shortening of chordae tendineae • Narrowing of mitral valve orifice
Pathophysiology • MVA 2 cm2 : increased left atrial pressure (LAP) is necessary for normal transmitral flow • MVA 1cm2 : LAP 25 mm Hg required→ PVP and PCWP→exertional dyspnea • Chronic elevation of LAP→pulmonary hypertension, tricuspid and pulmonary regurgitation → right heart failure
• Progressive dilation of the LA predisposes: – Mural thrombi: embolize in 20% of patients Patients at high risk: • over 35 years old • Atrial fibrillation with a low cardiac output • large LA appendage. – Atrial fibrillation: • in up to 40% of patients • decreases cardiac output by 20%
Clinical Manifestations • Histories of rheumatic fever, murmur • Dyspnea • Palpitations • Chest pain • Hemoptysis: a late finding • Edema • Thromboembolism: may be 1st symptom
Physical Exam • Low-pitched diastolic rumble • Opening snap • S1, Atrial fibrillation, P2 • Coexistent murmurs • RV heave • Elevated neck veins, hepatomegaly, ascites, pedal edema • Thromboembolic events