Frequency-domain analysis of heart rate variation has been suggested as an effective screening tool for sleep apnoea syndrome (SAS) in the general population. The aim of this study was to determine whether this method could be effective in patients with chronic congestive heart failure (CHF). 84 patients with stable CHF, left ventricular ejection fraction (LVEF) <45 %, and sinus rhythm were included prospectively. Patients underwent simultaneous polygraphy to measure apnoea/hypopnoea index (AHI) and ECG

Holter monitoring to measure the power spectral density of the very low frequency component of the heart rate increment, expressed as the percentage of total power spectral density (% VLFI).

VLFI could be determined in 54 patients (mean age 52.8+/-12.3 years and LVEF 33.5+/-9.8 %). SAS defined as AHI >=15•h-1 was diagnosed in 57.4 % of patients. % VLFI was not correlated with AHI (R=0.12). Receiver operating characteristic curves constructed using various AHI cut-offs (5 to 30.h-1) failed to identify a % VLFI cut-off associated with SAS. The 2.4 % VLFI cut-off recommended for the general population of patients with suspected SAS had low values for specificity (35 %), positive and negative predictive value (35 % and 54 % respectively). Heart rate increment analysis demonstrated several limitations in CHF. At this time, HRV methodology could not be proposed as the first step of SAS screening in CHF population.