Ventilatory assistance improves exercise endurance in stable congestive heart failure

Area of Science:

• Cardiopulmonary physiology
• Exercise science
• Respiratory medicine

Background:

• Chronic heart failure (CHF) significantly impairs exercise capacity and quality of life.
• Exertional symptoms like dyspnea and leg discomfort limit physical activity in CHF patients.
• Ventilatory assistance strategies are explored to improve exercise performance in CHF.

Purpose of the Study:

• To investigate the effects of ventilatory assistance on cardiopulmonary function, exertional symptoms, and exercise endurance in advanced CHF patients.
• To compare the efficacy of inspiratory pressure support (PS) versus continuous positive airway pressure (CPAP) during exercise.

Main Methods:

• 12 stable advanced CHF patients underwent randomized constant-load exercise tests.
• Ventilatory assistance included control (no support), optimized CPAP, and optimized PS.
• Measurements included cardioventilatory responses, esophageal pressure, and Borg ratings of dyspnea and leg discomfort.

Main Results:

• PS significantly reduced the work of breathing by 39% and increased exercise time limit (Tlim) by 43%.
• PS decreased leg discomfort and V̇O2 time slopes, correlating with increased Tlim.
• CPAP did not significantly alter measured exercise responses or endurance.

Conclusions:

• Ventilatory muscle unloading with PS effectively reduces exertional leg discomfort in stable advanced CHF.
• PS enhances exercise endurance in CHF patients primarily by mitigating leg discomfort.
• CPAP is less effective than PS in improving exercise parameters for CHF patients.