Cardiac diastolic function and hypercapnic ventilatory responses in central sleep apnoea

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