Cardiac diastolic function and hypercapnic ventilatory responses in central sleep apnoea

Abstract

Hyperventilation is the key factor contributing to the development of idiopathic nonhypercapnic central sleep apnoea (ICSA), where left ventricular systolic function is normal. ICSA is reported to occur in 20% of patients with left ventricular diastolic dysfunction, in whom elevated pulmonary vascular pressures and resultant increased pulmonary vagal afferent traffic may contribute to hyperventilation. The contribution of the two potential mechanisms responsible for the hyperventilation seen in the following ICSA was measured: 1) left ventricular diastolic dysfunction-induced pulmonary hypertension; and 2) increased peripheral and central hypercapnic ventilatory responses (HCVR).The pulmonary artery pressure, left ventricular diastolic function and chemosensitivity to hypercapnia were measured during wakefulness in 16 subjects with ICSA.All subjects had systolic pulmonary artery pressures v3.99 kPa (v30 mmHg) and only four had diastolic dysfunction. All subjects had elevated peripheral and central HCVR compared with historical normal control subjects. Diastolic dysfunction correlated with increasing age but not with HCVR or markers of central sleep apnoea severity.Idiopathic nonhypercapnic central sleep apnoea is likely to be dependent upon raised hypercapnic ventilatory responses, and not pulmonary hypertension due to left ventricular diastolic dysfunction. Eur Respir J 2002; 20: 717-723.

Prevalence and treatment of central sleep apnoea emerging after initiation of continuous positive airway pressure in patients with obstructive sleep apnoea without evidence of heart failure

“…The normalisation of respiration and elimination of central apnoeas by ASV in contrast to CPAP therapy supports observations that hyperventilation plays an important role in the pathophysiology of both CSR-CSA and CSA [3,4,20,35]. Hall et al [36] described only gradual differences between these two conditions.…”

Mechanisms of Apnea

“…Insomnia and daytime sleepiness are common symptoms. Elevated hypercapnic ventilatory responses (64, 70, 71) leading to increased propensity for hypocapnia and respiratory control instability are believed to be particularly important pathophysiolgical traits in ICSA. While arousal may play an important role in terminating hypopnea/apneas in patients with ICSA, the subsequent hypocapnia that develops appears to play an important role in further destabilization of breathing (60).…”

Ventilation Parameters under Adaptive Servo Ventilation: A Comparison on Behalf of CSA-Pattern, BNP/NT-pro-BNP, and Ejection Fraction

“…Solin et al [32] showed that hypercapnic ventilatory responses in patients with idiopathic central sleep apnoea were the same in patients with and without diastolic dysfunction. Mansfield et al [33] reported that a successful heart transplantation led to a switch from CSA-CSR to (I)CSA.…”