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Cardiac diastolic function and hypercapnic ventilatory responses in central sleep apnoea.
P Solin1, D M Jackson, T Roebuck
1Dept of Respiratory Medicine, The Alfred Hospital and Monash University Medical School, Melbourne, Victoria, Australia.
The European Respiratory Journal
|October 3, 2002
Summary
Idiopathic nonhypercapnic central sleep apnoea (ICSA) is driven by increased hypercapnic ventilatory responses (HCVR). Left ventricular diastolic dysfunction and associated pulmonary hypertension are not primary causes of ICSA-related hyperventilation.
Area of Science:
- Sleep Medicine
- Cardiology
- Respiratory Physiology
Background:
- Idiopathic nonhypercapnic central sleep apnoea (ICSA) is linked to hyperventilation.
- Left ventricular diastolic dysfunction (LVDD) may contribute to ICSA via pulmonary hypertension and vagal afferent activity.
- The relative roles of LVDD-induced pulmonary hypertension and altered hypercapnic ventilatory responses (HCVR) in ICSA hyperventilation are unclear.
Purpose of the Study:
- To investigate the contributions of LVDD-induced pulmonary hypertension and elevated HCVR to hyperventilation in patients with ICSA.
- To determine the relationship between LVDD, pulmonary vascular pressures, and HCVR in ICSA.
Main Methods:
- Measured pulmonary artery pressure, left ventricular diastolic function, and chemosensitivity to hypercapnia in 16 ICSA subjects during wakefulness.
- Compared HCVR in ICSA subjects to historical control data.
Main Results:
- All subjects exhibited elevated peripheral and central HCVR compared to controls.
- Only four subjects had diastolic dysfunction, and systolic pulmonary artery pressures were below hypertensive thresholds.
- Diastolic dysfunction correlated with age but not with HCVR or ICSA severity.
Conclusions:
- Raised hypercapnic ventilatory responses are the likely primary driver of hyperventilation in idiopathic nonhypercapnic central sleep apnoea.
- Pulmonary hypertension due to left ventricular diastolic dysfunction does not appear to be a significant contributor to ICSA.