In summary, MS is a progressive disease characterized by a long latent period between the initial attack of acute rheumatic fever and the development of symptoms. For patients with MS who require mechanical relief of obstruction PMV is the preferred treatment and gives results comparable to surgical commissurotomy. Two-dimensional echocardiographic assessment of mitral valve morphology is the most important predictor of outcome. An echocardiographic score <8 predicts good immediate and long-term results. In patients undergoing PMV, TEE is useful for detecting left atrial and left atrial appendage thrombi, guiding transseptal puncture, assessing results and detecting complications.