title: Cyclic variation in heart rate score by holter electrocardiogram as screening for sleep-disordered breathing in subjects with heart failure.
abstract: BACKGROUND
  Sleep-disordered breathing (SDB) is critically associated with cardiovascular mortality and morbidity, especially in patients with heart failure (HF). However, the majority of SDB patients remain undiagnosed. In contrast, abnormality in heart rate variability has been reported in patients with SDB. To explore an efficient electrocardiogram (ECG)-based screening tool for SDB, we examined the usefulness of cyclic variation in heart rate score (CVHRS) by Holter ECG in subjects with HF.
  
  
  METHODS
  In this study, 102 subjects with HF were enrolled. We simultaneously performed Holter ECG with overnight portable sleep monitoring, and we measured the respiratory disturbance index (RDI) and CVHRS. We determined the temporal position of the individual dips comprising the CVHRS using time-domain methods. CVHRS was measured as cyclic and autocorrelated dips in smoothed interbeat interval time series.
  
  
  RESULTS
  There were 25 subjects with severe SDB (RDI ≥ 30 events/h) and 77 subjects with none-to-moderate SDB (0 ≤ RDI < 30 events/h). There was a significant positive correlation between CVHRS and RDI (r = 0.60, P < .001). In receiver operating characteristic analysis, CVHRS (cutoff of 30 events/h) identified severe SDB with a sensitivity of 82%, a specificity of 77%, and an area under the curve of 0.83.
  
  
  CONCLUSIONS
  CVHRS determined by Holter ECG is a useful screening index for severe SDB in subjects with HF.
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: Department of Cardiology and Hematology Department of Advanced Cardiac Therapeutics, Fukushima Medical University, Fukushima, Japan. yoshihis@fmu.ac.jp.
authors.forename: Akiomi
authors.initials: A
authors.lastname: Yoshihisa
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Shoji
authors.initials: S
authors.lastname: Iwaya
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Abe
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Takamasa
authors.initials: T
authors.lastname: Sato
authors.affiliation: Department of Cardiology and Hematology Department of Advanced Cardiac Therapeutics, Fukushima Medical University, Fukushima, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Yamaki
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Koichi
authors.initials: K
authors.lastname: Sugimoto
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kunii
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakazato
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Cardiology and Hematology.
authors.forename: Shu-Ichi
authors.initials: S
authors.lastname: Saitoh
authors.affiliation: Department of Cardiology and Hematology Department of Advanced Cardiac Therapeutics, Fukushima Medical University, Fukushima, Japan.
authors.forename: Yasuchika
authors.initials: Y
authors.lastname: Takeishi
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D015716:Electrocardiography, Ambulatory; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012372:ROC Curve; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D013997:Time Factors
keywords: ECG-based screening; apnea; heart failure; heart rate variability; hypoxia; sleep-disordered breathing