1. Cardioventilatory coupling in heart rate variability: methods for qualitative and quantitative determination 
D.C. Galletly, P.D. Larsen 
British Journal of Anaesthesia 
Volume 87, Issue 6, Pages (December 2001)
DOI: /bja/
Copyright © 2001 British Journal of Anaesthesia Terms and Conditions

2. Fig 1
A 500-s epoch from a subject exhibiting 3:1 cardioventilatory coupling. (a) RR interval time series showing two distinct bands. (b) RI interval plot showing pattern I cardioventilatory coupling. (c) Normalized preceding RR interval plotted against the time an R wave occurs after inspiratory onset (IR interval). Note the clustering of heart beats in constant relationship with inspiratory onset (at t=0). (d) Representative detail of the variation in RR interval. (e) Consecutive difference time series (ΔRRn, ΔRRn+1,...). Two distinct bands are visible. (f) Consecutive difference phase portrait plot (ΔRRn vs ΔRRn+1). Three distinct clusters are seen, each corresponding to the variation between three consecutive RR intervals.
British Journal of Anaesthesia  , DOI: ( /bja/ )
Copyright © 2001 British Journal of Anaesthesia Terms and Conditions

3. Fig 2
A 450 s epoch from a subject in the absence of cardioventilatory coupling. (a) RR interval time series showing no banding. (b) RI interval plot showing no consistent timing relationship between R waves and inspiration, i.e. an uncoupled time series. (c) Normalized preceding RR interval plotted against the time an R wave occurs after inspiratory onset (IR interval). (d) Representative detail of the variation in RR interval. (e) Consecutive difference time series (ΔRRn, ΔRRn+1,...). No banding is visible. (f) Consecutive difference phase portrait plot (ΔRRn vs ΔRRn+1). A concentric ring shape is apparent.
British Journal of Anaesthesia  , DOI: ( /bja/ )
Copyright © 2001 British Journal of Anaesthesia Terms and Conditions