Impact of Inspiratory Muscle Training Versus Resistance Training on Ventricular Dysfunction in Patients With Dilated Cardiomyopathy: A Randomized Controlled Trial

Background: Dilated cardiomyopathy is a common cardiac dysfunction affecting patient's functional activities. Inspiratory muscle training retains the progression of the disease and improve cardiac functions. Objectives: To investigate the effect of inspiratory muscle training versus resistance training on left-ventricular dysfunction in patients with dilated cardiomyopathy. Materials and Methods: Thirty male patients with ischemic dilated cardiomyopathy were randomly assigned to either the Inspiratory Muscle Training (n = 15) or Resistance Training (n = 15) Groups. The Inspiratory Muscle Training Group received supervised aerobic training plus inspiratory muscle training at 40% of the maximal inspiratory pressure for 28 min once daily 3 days a week for 16 weeks. The Resistance Training Group received aerobic training plus resistance training (50-60% of the one-repetition maximum) in three sets per session 3 days a week for 16 weeks. Main measures: Left-ventricular end-diastolic and end-systolic diameters via echocardiography, left-ventricular ejection fraction, aerobic capacity, inspiratory muscle strength, and N-terminal prohormone of brain natriuretic peptide levels were assessed at baseline, after 16 weeks of training-based intervention, and at a 24-week followup. Results: The Inspiratory Muscle Training Group exhibited significantly greater improvements in left-ventricular end-diastolic and end-systolic diameters, left-ventricular ejection fraction, aerobic capacity, respiratory muscle strength, and N-terminal prohormone of brain natriuretic peptide levels than the Resistance Training Group (p > 0.05). These significant gains were maintained at a 24-week follow-up. Conclusion: Inspiratory muscle training has more significant effect in eliminating the left ventricular dysfunction than resistance training for patients with dilated cardiomyopathy.