title: Impact of sleep-disordered breathing on heart rate turbulence in heart failure patients.
abstract: BACKGROUND
  Sleep-disordered breathing (SDB) is associated with adverse outcomes in patients with chronic heart failure (CHF). Additionally, heart rate turbulence (HRT) reflects changes in the sinus cycle length of baroreceptor in response to hemodynamic fluctuations after ventricular premature beat. Recent studies have suggested that HRT as a marker of vagal activity has a predictive value of poor prognosis in CHF patients. However, little is known about the relationship between SDB and HRT in CHF patients.
  
  
  RESULTS
  In this study, 75 patients with CHF were enrolled. We simultaneously performed Holter ECG during a 24-hr period and portable sleep monitoring at nighttime, and determined the respiratory disturbance index (RDI), HRT (turbulence onset (TO) and turbulence slope (TS)) during that 24-hr period. These patients were divided into two groups based on the presence of severe SDB: Group A (RDI≥30, n = 17) and Group B (RDI<30, n = 58). TS was significantly lower in Group A than in Group B across the 24-hr period (nighttime: 3.6±1.1 vs. 6.9±1.3; daytime: 3.7±0.8 vs. 7.0±1.1; all-day: 3.5±0.7 vs. 6.7±0.9% ms/RR, P<0.05, respectively). TO did not differ between the two groups. Furthermore, there was a significant negative correlation between all-day TS and RDI (R = -0.257, P = 0.027). Moreover, in the multiple regression analysis, RDI was an independent factor to determine all-day TS.
  
  
  CONCLUSIONS
  In patients with severe SDB, blunted TS was observed across 24 hours. These results suggest that SDB induce impairment of vagal activity across a 24-hour period and may be associated with poor prognosis in CHF patients.
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan; Department of Advanced Cardiac Therapeutics, Fukushima Medical University, Fukushima, Japan.
authors: Akiomi
authors: A
authors: Yoshihisa
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan; Department of Advanced Cardiac Therapeutics, Fukushima Medical University, Fukushima, Japan.
authors: Satoshi
authors: S
authors: Suzuki
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Mai
authors: M
authors: Takiguchi
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Takeshi
authors: T
authors: Shimizu
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Satoshi
authors: S
authors: Abe
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Takamasa
authors: T
authors: Sato
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Takayoshi
authors: T
authors: Yamaki
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Koichi
authors: K
authors: Sugimoto
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Hiroyuki
authors: H
authors: Kunii
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Kazuhiko
authors: K
authors: Nakazato
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Hitoshi
authors: H
authors: Suzuki
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan.
authors: Shu-ichi
authors: S
authors: Saitoh
authors: Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan; Department of Advanced Cardiac Therapeutics, Fukushima Medical University, Fukushima, Japan.
authors: Yasuchika
authors: Y
authors: Takeishi
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D006333:Heart Failure / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012119:Respiration; D012893:Sleep Wake Disorders / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*