[Improvement in inspiratory muscle function in patients with mitral stenosis after percutaneous mitral valvuloplasty. Preliminary communication].
BACKGROUND: It has been proved that there is an inspiratory muscle dysfunction in mitral stenosis; Although its causes still remain unknown. AIM: To evaluate the effect of percutaneous balloon mitral valvuloplasty (PMV) on inspiratory muscle performance (IMP) in patients with mitral stenosis (mitral area < 1.5 cm2). PATIENTS AND METHODS: We studied IMP in 8 patients (35 +/- 10 years) before and 3 months after successful PMV. Inspiratory muscle strength was studied by measuring maximal statistical inspiratory mouth pressure (MIP). Endurance was evaluated using a two minute incremental threshold loading test in order to obtain the maximal sustainable inspiratory pressure (SIP), with the maximal sustainable load (MSL) the patients could sustain for 2 minutes. RESULTS: Mitral valvuloplasty increased mean cardiac index from 3.1 +/- 0.3 to 4.15 +/- 0.3 l/min/m2 (p < 0.01), and significantly decreased mean pulmonary and capillary pressures. The MIP value(118 +/- 6 cmH2O), similar to that of normal group, increased to 137 +/- 7 cmH2O (p < 0.01). SIP and maximal sustainable load were 52 +/- 3 cmH2O and 294 +/- 29 g respectively, lower than normal subjects (p < 0.05). They increased after PMV to 80 +/- 3 cmH2O and 463 +/- 26 g respectively (p < 0.001). CONCLUSIONS: PMV improved inspiratory muscle function in patients with severe mitral stenosis, probably secondary to a decrease work of breath and improvement of ventricular function.