Background: There is a high prevalence of central sleep apnea (CSA) in patients with chronic heart failure (CHF). The present study investigates the hypotheses that CSA in CHF patients reflects heart failure severity as measured by cardiac index (CI), pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure (PCWP).
Methods: In 105 patients with stable CHF (NYHAII, LV-EF40%) cardiorespiratory polygraphy and simultaneous right and left heart catheterization was performed.
Results: CSA was present in 58% and obstructive sleep apnea (OSA) in 23% of patients. In CSA patients, PAP and PCWP were significantly higher when compared to patients without SDB. In CSA patients, but not in OSA patients, PCWP showed a significant correlation with apnea-hypopnea index (AHI; r=0.41, p=0.005), apnea index (AI; r=0.44, p=0.003) and central AI (cAI; r=0.358, p=0.015). Cardiac index was more impaired in CSA (1.93+/-0.5 l/min/m(2)) than in OSA patients (2.55+/-1.0 l/min/m(2)) or those without SDB (2.22+/-0.4 l/min/m(2)). A negative correlation of CI and cAI (r=-0.344, p=0.008), AI (r=-0.31, p=0.02) and AHI (r=-0.21, p<0.05) was documented exclusively in CSA patients.
Conclusion: The present study supports the hypotheses that the occurrence and severity of CSA in CHF patients reflects heart failure severity.