Mitral stenosis is the narrowing of the mitral valve in the heart. The most common cause is rheumatic fever resulting in rheumatic mitral stenosis. Patients present with exertional shortness of breath, chest pain, cough, coughing up blood (haemoptysis) and swelling of legs. Diagnosis is by echocardiography which shows the narrowed valve and increased pressure gradient across the valve. Treatment is by percutaneous balloon mitral valvuloplasty or open surgery requiring a valve replacement.