title: Correlations between the Poincaré plot and conventional heart rate variability parameters assessed during paced breathing.
abstract: OBJECTIVE
  To analyze the correlation of the Poincaré plot descriptors of RR intervals with standard measures of heart rate variability (HRV) and spontaneous baroreflex sensitivity (BRS). A physiological model of changing respiratory rates from 6 to 15 breaths/min provided a wide range of RR intervals for analysis.
  
  
  METHODS
  Beat-to-beat finger blood pressure, ECG, and respiratory curves were recorded noninvasively in 15 young healthy volunteers (19-25 years old; 7 females) breathing for 5 min at 4 different respiratory rates of 6, 9, 12, and 15 breaths/min. Four descriptors of the Poincaré plot (SD1, SD2, S, and SD2/SD1), time and frequency domain HRV, and spontaneous BRS (cross-correlation method) were calculated for each 5-min recording.
  
  
  RESULTS
  The values of SD1 characterizing short-term HRV, SD2 describing long-term HRV, and S measuring total HRV were significantly correlated with BRS and time and frequency domain measures of short, long, and total HRV. The LF/HF significantly correlated with SD2 and SD2/SD1 representing the balance between long- and short-term HRV. None of the Poincaré plot descriptors was correlated with the mean RR interval. The increased respiratory rate caused a significant reduction of BRS, measures of total and long-term HRV, and an increase of HF that peaked at 12 breaths/min.
  
  
  CONCLUSIONS
  The descriptors of the Poincaré plot of RR intervals are significantly correlated with measures of BRS and time and frequency domain HRV, but not with heart rate. A faster respiratory rate reduces long-term HRV measures and temporarily increases HF.
authors.affiliation: Department of Cardiology-Intensive Therapy, University of Medical Sciences in Poznań, Przybyszewskiego 49, 60-355 Poznan, Poland. pguzik@ptkardio.pl.
authors.forename: Przemysław
authors.initials: P
authors.lastname: Guzik
authors.forename: Jarosław
authors.initials: J
authors.lastname: Piskorski
authors.forename: Tomasz
authors.initials: T
authors.lastname: Krauze
authors.forename: Raphael
authors.initials: R
authors.lastname: Schneider
authors.forename: Karel H
authors.initials: KH
authors.lastname: Wesseling
authors.forename: Andrzej
authors.initials: A
authors.lastname: Wykretowicz
authors.forename: Henryk
authors.initials: H
authors.lastname: Wysocki
mesh_terms: D000328:Adult; D017704:Baroreflex; D001794:Blood Pressure; D002320:Cardiovascular Physiological Phenomena; D004562:Electrocardiography; D005260:Female; D005385:Fingers / Q000098:blood supply; D006339:Heart Rate; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D012016:Reference Values; D015203:Reproducibility of Results; D012107:Research Design; D015656:Respiratory Mechanics; D012143:Respiratory Physiological Phenomena; D013997:Time Factors