Introduction Enhanced respiratory muscle strength in patients with heart failure
positively alters the clinical trajectory of heart failure. In an
experimental model, respiratory muscle training in rats with heart failure
has been shown to improve cardiopulmonary function through mechanisms yet to
be entirely elucidated.ObjectiveThe present report aimed to evaluate the respiratory muscle training effects
in diaphragm citrate synthase activity and hemodynamic function in rats with
heart failure.MethodsWistar rats were divided into four experimental groups: sedentary sham
(Sed-Sham, n=8), trained sham (RMT-Sham, n=8), sedentary heart failure
(Sed-HF, n=7) and trained heart failure (RMT-HF, n=7). The animals were
submitted to a RMT protocol performed 30 minutes a day, 5 days/week, for 6
weeks.ResultsIn rats with heart failure, respiratory muscle training decreased pulmonary
congestion and right ventricular hypertrophy. Deleterious alterations in
left ventricular pressures, as well as left ventricular contractility and
relaxation, were assuaged by respiratory muscle training in heart failure
rats. Citrate synthase activity, which was significantly reduced in heart
failure rats, was preserved by respiratory muscle training. Additionally, a
negative correlation was found between citrate synthase and left ventricular
end diastolic pressure and positive correlation was found between citrate
synthase and left ventricular systolic pressure.ConclusionRespiratory muscle training produces beneficial adaptations in the
diaphragmatic musculature, which is linked to improvements in left
ventricular hemodynamics and blood pressure in heart failure rats. The
RMT-induced improvements in cardiac architecture and the oxidative capacity
of the diaphragm may improve the clinical trajectory of patients with heart
failure.