Phase asymmetry of heart rate variability signal

Abstract

Heart rate asymmetry (HRA) is considered as a physiological phenomenon in healthy subjects. In this article, we propose a novel HRA index, Slope Index (SI), to quantify phase asymmetry of heart rate variability (HRV) system. We assessed the performance of proposed index in comparison with conventional (Guzik's Index (GI) and Porta's Index (PI)) HRA indices. As illustrative examples, we used two case studies: (i) differentiate physiologic RR series from synthetic RR series; and (ii) discriminate arrhythmia subjects from Healthy using beat-to-beat heart rate time series. The results showed that SI is a superior parameter than GI and PI for both case studies with maximum ROC area of 0.84 and 0.82 respectively. In contrast, GI and PI had ROC areas {0.78, 0.61} and {0.50, 0.56} in two case studies respectively. We also performed surrogate analysis to show that phase asymmetry is caused by a physiologic phenomena rather than a random nature of the signal. In conclusion, quantification of phase asymmetry of HRV provides additional information on HRA, which might have a potential clinical use to discriminate pathological HRV in future.

Heart Rate Asymmetry in Response to Colored Light

“…RR interval series were created using corrected QRS peaks. and below identity line (IL) [9,10] and can be visually observed in Poincaré plot, plot of each RR interval against next RR interval. If we represent n th RR interval as RRn and define ΔR as RRn+1-RRn, IL in Poincaré Plot corresponds to ΔR=0.…”

“…Also, deceleration and acceleration of heart rate correspond to points above IL (PA=ΔR>0) and below IL (PB=ΔR<0), respectively. In this paper, Porta Index [15], Guzik Index [10], and Slope Index [9] were calculated within five minutes time windows across stimulations with different colored light to quantitatively represent HRA:…”

“…where, + and − are distances of points above and below IL from identity line, respectively. 3-Slope Index (SI): SI is defined as a percentage of phase angle difference of points above IL with respect to the total phase angle difference [9]:…”

“…Heart rate asymmetry (HRA) is a new approach to quantify changes (e.g., increase or decrease) in heart rate with respect to previous heart beat [8][9][10] and is shown to be different in diabetes patients compared to healthy individuals [11] as well as in people with different stress level [12].…”

Short-term recovery of heart rate variability and its relationship with blood pressure after different intensity treadmill exercise

“…Then, the change was fed back to medulla again, these receptors adjusted flowed-pressure by altering HR and BP [52][53][54][55] Complementary to traditional time and frequency parameters, non-linear indices were able to identify the different patterns of autonomic regulation after different intensity exercise. HRA was described as a visible phenomenon, which quantified imbalance of heart rate acceleration and deceleration using a two-dimension Poincaré plot [39,40,56]. It was reported to mostly present in healthy participants under resting condition and decrease with pathology [57,58].…”