Yatsu S, Kasai T, Naito R, et al. - Whether cyclic variation of heart rate (CVHR) has utility as a screening instrument for sleep-disordered breathing (SDB) in mixed heart failure (HF) and non-HF patients, was inquired herein. Participants were consecutive patients with and without HF who had full polysomnographies with simultaneous Holter electrocardiogram monitoring. Analysis involved data of 101 patients, including 70 with and 31 without HF. As shown by receiver operating characteristic analysis, severe SDB was detected by the CVHR score (best cut-off of 23.5 events/h), with a sensitivity and specificity of 83.3% and 79.5%, respectively, and an area under the curve of 0.856 was generated. Findings demonstrate the usefulness of the CVHR score, determined by Holter electrocardiogram monitoring, as an instrument for assessing SDB even in mixed HF and non-HF patients.