Abstract 2405: Acute Increase In Left Ventricular Filling Pressure Leads To Hyperventilation In Heart Failure Patients With Central But Not Obstructive Sleep Apnea Or Without Sleep Disordered Breathing
The pathohysiology of Cheyne-Stokes-respiration (CSR) in congestive heart failure (CHF) is not fully understood. Increase in pulmonary capillary wedge pressure (PCWP) may lead to stimulation of pulmonary J-receptors and consecutive hyperventilation. The present study investigates the influence of an acute increase in PCWP in CHF pts without sleep disordered breathing (SDB) compared to pts with central (CSR) and obstructive sleep apnea (OSA). Simultaneous left and right heart catheterizations were performed in 29 CHF pts (NYHA ≥ II, LVEF ≤ 40%). PCWP and arterial pCO2 were measured under standardized settings at baseline and after left ventricular angio- and/or aortography resulting in an acute increase in intravascular volumes. Type and severity of SDB were determined by cardiorespiratory polygraphy the night before or thereafter. NT-proBNP concentration was measured and central CO2 - receptor sensitivity determined by testing hypercapnic-hyperoxic-ventilatory response (HCVR) according to Read. CSR was diagnosed in 15 pts (apnea-hypopnoea-index [AHI] 32 ± 19/h; 59 ± 11 years; LVEF 32 ± 6%), OSA in 9 pts (AHI 27 ± 29/h; 64 ± 13 years; LVEF 33 ± 5%); 5 pts had no SDB (AHI 1 ± 2/h; 48 ± 13 years; LVEF 32 ± 7%). HCVR and NT-proBNP concentrations were significantly higher in CSR (5.6 ± 6.5l/min/mmHg and 5237 ± 6268pg/ml) compared to OSA (2.2 ± 0.6l/min/mmHg and 1127 ± 874pg/ml) or pts without SDB (1.6 ± 0.6l/min/mmHg and 197 ± 146pg/ml; p < 0.05). PCWP were elevated at baseline and increased significantly after angiography in all groups (CSR: 20.3 ± 6.6 mmHg to 22.9 ± 7.9 mmHg; OSA 22.8 ± 10 to 25.4 ± 11 mmHg; noSDB: 14.2 ± 10 to 17.4 ± 9mmHg; all p < 0.05). Arterial pCO2 at baseline tended to be lower in pts with CSR. Only in CSR, not in OSA or pts without SDB increase in PCWP was accompanied by a further decrease in pCO2 (CSR: 36.1 ± 5mmHg to 33.3 ± 5mmHg, p = 0.05; OSA: 38.7 ± 4mmHg to 40.1 ± 6mmHg, p = ns; noSDB: 39.6 ± 6mmHg to 39.7 ± 6mmHg, p = ns). In CHF pts with CSR but not in those without SDB or OSA, acute increase in PCWP stimulates ventilation, together with other factors like an increased central CO2 - receptor sensitivity this may lead to hyperventilation and a consecutive decrease in pCO2 below the apnea threshold. Moreover, the present data may explain why CSR in some pts reflects CHF severity.