Selective training of respiratory muscles in patients with chronic heart failure

Background: Patients with chronic heart failure have a lower inspiratory mu scle strength and fatigue endurance. Aim: To assess the effects of selectiv e training of respiratory muscles in patients with heart failure. Patients and methods: Twenty patients with stable chronic heart failure, aged 58.3+/ -3 years with an ejection fraction of 28+/-9%, were subjected to respirator y muscle training with threshold valves. The load was fixed in 30% of maxim al inspiratory pressure (PImax) in 11 and in 10% of PImax in nine. Two sess ions of 15 minutes, 6 days per week, during 6 weeks were done. Degree of dy spnea (Mabler score), maximal oxygen uptake, distance walked in 6 minutes, respiratory muscle function and left ventricular ejection fraction were mea sured before and after training. Results: Both training loads were associat ed to an improvement in dyspnea (+2.7+/-1.8 and +2.8+/-1.8 score points wit h 30% PImax and 10% PImax respectively), maximal oxygen uptake (from 19+/-3 to 21.6+/-5 and from 16+/-5 to 18.6+/-7 ml/kg/min with 30% PImax and 10% P Imax respectively, p<0.05, PImax (from 78+/-22 to 99+/-22 and from 72+/-34 to 82.3 cm H2O with 30% PImax and 10% PImax respectively), sustained PImax (from 63+/-18 to 90+/-22 and from 58+/-3 to 69+/-3 cm H2) with 30% PImax an d 10% PImax respectively), and maximal sustained load (from 120+/-67 to 195 +/-47 and from 139+/-120 to 192+/-154 g with 30% PImax and 10% PImax respec tively). The distance walked in 6 min only increased in subjects trained at 30% PImax (from 451+/-78 to 486+/-68 m). Conclusions: Selective training o f respiratory muscles results in a functional improvement of patients with chronic heart failure.