Correlation of Lorenz Scatterplots With Frequency-Domain Heart Rate Variability

Abstract

Heart rate (HR) variability is important with respect to disease prognosis and the effects of drugs. Lorenz scatterplots provide a simple way to evaluate HR variability visually. The relation of Lorenz scatterplots to frequency-domain HR variability was examined in 75 Holter recordings and in simulated HR trends. The length of Lorenz scatterplots was double-exponentially correlated with total frequency and very-low frequency powers, with correlation coefficients (r) of 0.88. The width of Lorenz scatterplots was highly correlated with the high frequency power (r=0.98). The sum of the width and length of Lorenz scatterplots was highly correlated with the total frequency power (r=0.92). Identical results were obtained when simulated HR trends were used. In conclusion, Lorenz scatterplots provide a simple way to estimate the frequency-domain HR variability.

Cardiac Arrhythmias Imprint Specific Signatures on Lorenz Plots

“…It has often been assumed that the different LP shapes are due to variations in efferent sympathetic and parasympathetic activity, 8–10 and conclusions have been drawn as to the prognostic value of the LP method in cardiac risk stratification 4–10 . However, the contribution of arrhythmias to the LP shapes has not been adequately considered.…”

“…Numerous clinical studies 1–12 have demonstrated that an interval series obtained during sinus rhythm with well‐preserved heart rate variability will produce a cluster of points grouped around the bisector with a club like appearance. According to accepted nomenclature 4–7 such a pattern is usually referred to as a “comet” shape (Fig.…”

“…In contrast, reduced heart rate variability has been shown 4–11 to be associated with a cigar like LPP (Fig. 3B), which is commonly referred to as “torpedo shape.” 4–7 Experimental correlation studies 8, 9 have concluded that the width of the comet or torpedo pattern is a marker of instantaneous heart rate variability, while the length of the comet or torpedo pattern is related to overall heart rate variability. Recently, these conclusions have been corroborated in computer simulations using a physiologically extended firing HRV model 10 …”

“…After publication of the famous article by Lorenz on chaotic dynamics, 3 Poincaré plots have become broadly popular; hence they are also often referred to as Lorenz plots (LPs). More recently, Lorenz plots have been introduced into medicine by Woo et al, 4–6 whose work has elicited considerable interest and spurred an ever‐increasing number of studies using LP graphic representation of the heart rate data 7–12 . In this context, comet and torpedo like LP shapes have been extensively investigated and used for both graphic display and quantitative assessment of HRV 4–12 .…”

“…More recently, Lorenz plots have been introduced into medicine by Woo et al, 4–6 whose work has elicited considerable interest and spurred an ever‐increasing number of studies using LP graphic representation of the heart rate data 7–12 . In this context, comet and torpedo like LP shapes have been extensively investigated and used for both graphic display and quantitative assessment of HRV 4–12 . However, in spite of the growing number of studies using LPs for HRV evaluation, a possible correlation between the underlying ECG waveforms and scatter plots has never been systematically investigated and the effects of major cardiac arrhythmias on LP shapes are widely unknown.…”