ABSTRACT
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 ñ 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 ñ 0.3 to 4.15 ñ 0.3 l/min/m2 (p<0.01), and significantly decreased mean pulmonary and capillary pressures. The MIP value(118 ñ 6 cmH2O), similar to that of normal group, increased to 137 ñ 7 cmH2O (p<0.01). SIP and maximal sustainable load were 52 ñ 3 cmH2O and 294 ñ 29 g respectively, lower than normal subjects (p<0.05) They increased after PMV to 80 ñ 3 cmH2O and 463 ñ 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