Mitral valve is the target in most of patients having rheumatic fever. Detailed information on 1136 adults patients with pure mitral stenosis included chambers dimensions (left atrium, left vetricle and right ventricle), trans-valvular gradient (MVG), mitral valve area (MVA) systolic pulmonary artery pressure (SPAP) as documented by tricuspid regurgitation on two dimensional echocardiography and calculated by doppler was obtained. Mitral valve gradient increases to 5 mmHg when the area is 2.1cm. MVG increaseds to 10mmHg when MVA is 1.4cm. Left atrium starts increasing as MVA decreases below 2.18cm. Pulmonary artery pressure as estimated by tricuspid regugitation increased beyond 30mmHg when MVG increases more than 8mmHg and increases to 45mmHg when MVG increases to 12mmHg. pulmonary artery pressure increase to 60mmHg when MVG increases to 13mmhg. Pulmonary pressure increass above 45 mmHg as MVA decreases to 1.4cm. Patients develop severe pulmonary hypertension as pressure escalates to 60mmHg when MVA reduces below 0.8cm. MVA is the major criterion for classifying the severity of MS. In patients with MVA less than 1.5cm seem have severe MS as LA is enlarged and SPAP is elevated. Early intervention may be considered in patients with MVA less than 1.5cm.