Background: Orthopnoea and paroxysmal nocturnal dyspnoea are common entities regularly confronting thoracic physicians, particularly those with an interest in sleep medicine or non-invasive ventilatory support. One major cause is heart failure (HF), usually associated with abnormal lung function tests, and either obstructive or central sleep apnoea with Cheyne-Stokes respiration (CSA-CSR). Whereas obstructive apnoea is considered injurious to the cardiovascular system, the effects of CSA-CSR are less clear and may be a compensatory response to severe HF.
Aim: To determine whether there are compensatory or possibly beneficial aspects caused by CSA-CSR in HF.
Methods: Literature review.
Results: CSA-CSR can be detrimental in terms of intermittent hypoxaemia, arousals and autonomic dysregulation. However, it is also associated with the beneficial effects of hyperventilation-related increases in end-expiratory lung volume, intrinsic positive airway pressure, assistance to stroke volume, attenuation of excessive sympathetic nervous activity, avoidance of hypercapnic acidosis and finally the provision of periodic rest to fatigue-prone respiratory pump muscles.
Conclusions: CSA-CSR has physiological features more likely to be compensatory and beneficial than injurious in HF. Some aspects of CSA-CSR are similar to those seen with positive airway pressure.