PoincarePlot function

Poincare Plot

The Poincare plot is a graphical representation of the dependance between successive RR intervals obtained by plotting the $RR_(j+tau)$

as a function of $RR_j$. This dependance is often quantified by fitting an ellipse to the plot. In this way, two parameters are obtained: $SD_1$ and $SD_2$. $SD_1$ characterizes short-term variability whereas that $SD_2$ characterizes long-term variability.

PoincarePlot(
  HRVData,
  indexNonLinearAnalysis = length(HRVData$NonLinearAnalysis),
  timeLag = 1,
  confidenceEstimation = FALSE,
  confidence = 0.95,
  doPlot = FALSE,
  main = "Poincare plot",
  xlab = "RR[n]",
  ylab = paste0("RR[n+", timeLag, "]"),
  pch = 1,
  cex = 0.3,
  type = "p",
  xlim = NULL,
  ylim = NULL,
  ...
)

Arguments

• HRVData: Data structure that stores the beats register and information related to it
• indexNonLinearAnalysis: Reference to the data structure that will contain the nonlinear analysis
• timeLag: Integer denoting the number of time steps that will be use to construct the dependance relation: $RR_(j+timeLag)$ as a function of $RR_j$.
• confidenceEstimation: Logical value. If TRUE, the covariance matrix is used for fitting the ellipse and computing the $SD_1$ and $SD_2$ parameters (see details). Default: FALSE.
• confidence: The confidence used for plotting the confidence ellipse.
• doPlot: Logical value. If TRUE (default), the PoincarePlot is shown.
• main: An overall title for the Poincare plot.
• xlab: A title for the x axis.
• ylab: A title for the y axis.
• pch: Plotting character (symbol to use).
• cex: Character (or symbol) expansion.
• type: What type of plot should be drawn. See plot.default.
• xlim: x coordinates range. If not specified, a proper x range is selected.
• ylim: y coordinates range. If not specified, a proper y range is selected.
• ...: Additional parameters for the Poincare plot figure.

Returns

A HRVData structure containing a PoincarePlot field storing the $SD_1$ and $SD_2$ parameters. The PoincarePlot field is stored under the NonLinearAnalysis list.

Details

In the HRV literature, when timeLag = 1, the $SD_1$ and $SD_2$

parameters are computed using time domain measures. This is the default approach in this function if timeLag=1. This function also allows the user to fit a ellipse by computing the covariance matrix of ($RR_(j)$,$RR_(j+tau)$) (by setting confidenceEstimation = TRUE). In most cases, both approaches yield similar results.

Examples

## Not run:

 data(HRVProcessedData)
 # rename for convenience
 hd = HRVProcessedData
 hd = CreateNonLinearAnalysis(hd)
 hd = PoincarePlot(hd, doPlot = T)
## End(Not run)