Heart rate asymmetry by Poincaré plots of RR intervals

Abstract

The Poincaré plot is a widely used method for visualizing and calculating heart rate variability and for investigating the oscillatory nature of heart action. We show that the Poincaré plot produced using physiological data for RR intervals is asymmetric. This suggests that the processes of heart rate acceleration (shortening of consecutive RR intervals) and deceleration (prolongation of successive RR intervals) might be asymmetric. To investigate this phenomenon, we define descriptors quantifying the heart rate asymmetry and present the results of a study involving 5-min ECG recordings of 50 healthy subjects in which, despite of the shortness of the recordings, the asymmetry is clearly visible.

Asymmetric features of short-term blood pressure variability

“…[10][11][12][13]16,23 In this plot for SBP (Figure 1), each SBP is a function of the preceding SBP, that is, the value of SBP of the current cardiac beat (SBP n ) is represented on the x-axis, and the value of SBP of the next beat (SBP n+1 ) on the y-axis. In this way each point (SBP n , SBP n+1 ) in the plot corresponds to two successive SBP values.…”

“…In this way each point (SBP n , SBP n+1 ) in the plot corresponds to two successive SBP values. The following descriptors of Poincaré plots of SBP were calculated with in-house software written in Python (Python Software Foundation, www.python.org, Wolfeboro Falls, NH, USA): [10][11][12][13]16,23 SD1 2 -the square of the s.d., or variance, quantifying the dispersion of all points in the plot across the identity line-this parameter is a measure of short-term SBP variance (SD1 2 ), that is, the short-term BPV, and according to the variance properties, SD1 2 can be decomposed into two parts, that is, SD1 i 2 and SD1 r 2 : SD1 i 2 -the part of SD1 2 contributed by the points in the Poincaré plot above the identity line-these points correspond only to SBP increases. SD1 r 2 -the part of SD1 2 contributed by the points in the Poincaré plot below the identity line-these points correspond only to SBP reductions.…”

“…[1][2][3][4][5][6][7][8][9][10][11]13 Recently, however, some methods, which allow separate analysis of decelerations and accelerations of heart rate or increases (i) and reductions (r) in blood pressure, have been described. 12,15,16 Among them are such techniques like phase-rectified signal averaging or variance partitioning by Poincaré plot. 12,15,16 The Poincaré plot analysis of RR intervals was used to show the existence of the physiological phenomenon of heart rate asymmetry in young healthy individuals.…”

“…12,15,16 Among them are such techniques like phase-rectified signal averaging or variance partitioning by Poincaré plot. 12,15,16 The Poincaré plot analysis of RR intervals was used to show the existence of the physiological phenomenon of heart rate asymmetry in young healthy individuals. 12,16 At supine rest, the prolongations of cardiac cycles usually have a significantly larger contribution to shortterm HRV than shortenings, and this unidirectional phenomenon is present in the majority (480%) of electrocardiography (ECG) recordings.…”

“…12,15,16 The Poincaré plot analysis of RR intervals was used to show the existence of the physiological phenomenon of heart rate asymmetry in young healthy individuals. 12,16 At supine rest, the prolongations of cardiac cycles usually have a significantly larger contribution to shortterm HRV than shortenings, and this unidirectional phenomenon is present in the majority (480%) of electrocardiography (ECG) recordings. 12,16 Porta et al 17 have also shown that the number of prolongations of RR intervals is significantly smaller than the number of shortenings.…”