Effects of Addition of Inspiratory Muscle Training to Exercise-Based Cardiac Rehabilitation on Inspiratory Muscle Strength, Peak Oxygen Consumption, and Selected Hemodynamics in Chronic Heart Failure

Background: Evidence supports the clinical benefits of isolated inspiratory muscle training (IMT) in patients with chronic heart failure (CHF); however, the rationale of IMT in combination with exercise training in cardiac rehabilitation settings for CHF has yet to be confirmed. Objective: This study aimed to assess the effect of the addition of IMT in combination with aerobic/resistance training (AT/RT) on maximal inspiratory pressure (Plmax), peak oxygen consumption (VO2peak), selected hemodynamic variables, and health-related quality of life (HRQoL) compared to sham-IMT combined with AT/RT in patients with CHF. Methods: Twenty-five male patients with CHF completed a 6-month cardiac rehabilitation program of either a sham-IMT/AT/RT program (control group, 51.84 +/- 4.56 years old, n(1) = 13), or a real-IMT/AT/RT program (study group, 51.75 +/- 4.73 years old, n(2) = 12). Inclusion criteria were ischemic heart failure, New York Heart Association (NYHA) class II-III, and reduced ejection fraction. Outcome measures were Plmax, VO2peak, resting heart rate (RHR), heart rate (HR) reserve, rate pressure product (RPP), left-ventricular ejection fraction, and Minnesota Living with Heart Failure Questionnaire (MLwHEQ). Absolute mean changes from baseline (Delta) in the outcome measures were statistically analyzed as independent outcomes. Results: Delta Plmax, Delta RHR, Delta HR reserve, and Delta MLwHFQ total score were significantly greater in the study group than in the control group (p <0.05). In addition, Delta RPP showed an observed difference in favor of the study group with a tendency towards statistical significance (p = 0.07). Conclusions: IMT could be a successful complementary intervention to exercise-based cardiac rehabilitation programs comprising AT/RT, yielding greater improvements in Plmax, RHR, HR reserve, and HRQoL in male patients with ischemic heart failure (NYHA class II-III).