Detection of arrhythmias is facilitated using irregularity of ventricular
beats measured by delta-RR (RR) intervals that exhibit discriminatory signatures
when plotted in a Lorenz scatter-plot. An "AF signature metric" is established
characteristic of episodes of AF that exhibit highly scattered (sparse) distributions
or formations of 2-D data points. An "AFL signature metric" is established characteristic
of episodes of AFL that exhibit a highly concentrated (clustered) distribution
or formation of 2-D data points. A set of heart beat interval data is quantified
to generate highly scattered (sparse) formations as a first discrimination metric
and highly concentrated (clustered) distributions or formations as a second discrimination
metric. The first discrimination metric is compared to the AF signature metric,
and/or the second discrimination metric is compared to the AFL signature metric.
AF or HFL is declared if the first discrimination metric satisfies either one of
the AF signature metric.