A method and apparatus for method for discriminating heart rhythms includes computing
a first predetermined number of RR intervals from received QRS intervals, and computing
a median RR interval corresponding to a predetermined number of the first predetermined
number of RR intervals. A predetermined beat-to-beat variation and a corresponding
predetermined count are determined based on the computed median RR interval. Beat-to-beat
variation differences between the first predetermined number of RR intervals are
computed and a determination is made as to whether the computed beat-to-beat variation
differences are greater than the predetermined beat-to-beat variation, and as to
whether a number of the computed beat-to-beat variation differences that are greater
than the predetermined beat-to-beat variation is greater than the predetermined
count. The heart rhythm is identified as an irregular rhythm in response to the
number being greater than or equal to the predetermined count.
