Patent ID: 8019407

Claim:
A heart monitor that processes input signals that represent periodically reoccurring events in a sequence of heart cycles, comprising: a signal input; an event detector connected to said signal input wherein said event detector is configured to respond to signal features that represent reoccurring cardiac events obtained via said signal input; at least one timer connected to said event detector and configured to determine an interval duration or its inverse of a time interval between two successive signal features that represent a cardiac event in respective heart cycles; an interval evaluation stage connected to said at least one timer and configured to determine a derivative of said interval duration of two successive time intervals or an inverse thereof; a processing stage connected to said interval evaluation stage and said at least one timer and configured to generate graphical data that represents a scatter plot of at least two dimensions, one dimension that represents said interval duration or its inverse and another dimension that represents said derivative of said interval duration or its inverse respectively, wherein the scatter plot comprises data points of which each data point represents the interval duration or its inverse plotted against said derivative of said interval duration with respect to a neighboring interval or the inverse of said derivative of said interval duration respectively; an analyzer stage wherein said processing stage is connected to said analyzer stage wherein said analyzer stage is configured to process said graphical data and to detect a cluster of data points in said scatter plot and to generate one or more metric, that depends on a location of one or more clusters of data points in said scatter plot; and, said analyzer stage further configured to utilize any combination of said generated one or more metric associated with said data points of which each said data point represents the interval duration or its inverse plotted against said derivative of said interval duration with respect to said neighboring interval or the inverse of said derivative of said interval duration respectively, wherein said one or more metric is selected from a count of non-zero cells, a count of non-zero columns, a count of non-zero rows, a count of local peaks, a total trajectory distance along RR axis, a total trajectory distance along dRR axis, a distance to global center, a distance to positive center, a distance to negative center.