['Dyspnea is a common symptom in a patient with valvular heart disease. The mechanism underlying this disease is still uncertain. Respiratory muscle weakness has been proposed to be one of the mechanisms underlying dyspnea in heart failure, but this has not been adequately studied in valvular heart disease.', 'We prospectively studied 20 patients with rheumatic mitral valve stenosis who were candidates for percutaneous balloon mitral valvotomy. Respiratory muscle strength assessment by maximal static inspiratory mouth pressure and maximal static expiratory mouth pressure was done on all patients at baseline and at 1 week after the procedure. The severity of dyspnea in study participants was also studied by the 6-min walk test and visual analog scale.', 'Balloon valvotomy was followed by a significant improvement in the 6-min walking distance (from 219 +/- 30.15 to 237.55 +/- 32.25 m, P < 0.001), visual analog scale as a measure of dyspnea (from 60.95 +/- 12.16 to 44.4 +/- 13.71 mm, P < 0.001), inspiratory muscle strength (from 51.9 +/- 10.28 to 56.55 +/- 11.87 cmH2O, P < 0.001) and expiratory muscle strength (from 62.15 +/- 19.68 to 67.20 +/- 21.91 cmH2O, P < 0.001).'] Does respiratory muscle strength in rheumatic mitral stenosis improve after balloon valvotomy?