Sleep-disordered breathing in heart failure with normal left ventricular ejection fraction

In patients with systolic heart failure (SHF) a high prevalence of sleep-disordered breathing (SDB) has been documented. The purpose of this study was to investigate the prevalence and type of SDB in patients with heart failure with normal left ventricular ejection fraction (HFNEF). Two hundred and forty-four consecutive patients (87 women, aged 65.3 +/- 1.4 years) with HFNEF underwent capillary blood gas analysis, measurement of NT-proBNP concentrations, echocardiography, cardiopulmonary exercise testing (CPX), cardiorespiratory polygraphy, and simultaneous right and left heart catheterization. Sleep-disordered breathing was defined as an apnoea-hypopnoea-index (AHI) >= 5/h. Sleep-disordered breathing was documented in 69.3% of all patients, 97 patients (39.8%) presented with OSA and 72 patients (29.5%) with CSA. With an increasing impairment of diastolic function the proportion of SDB, and CSA in particular, increased. Patients with SDB performed worse on CPX and six-minute walk test. Partial pressure of CO2 was lower in CSA, whereas AHI, left atrial diameter, NT-proBNP, LVEDP, PAP, and PCWP were higher. There is a high prevalence of SDB in HFNEF. In parallel to SHF, CSA patients in particular are characterized by a more impaired cardiopulmonary function. Whether SDB is of prognostic relevance in HFNEF needs to be determined.