2.3 Reproducibility of RR interval variability of VT
We examined the reproducibility of RR interval variability of VT from
two perspectives, firstly, reproducibility within an episode (RE), and
secondly, reproducibility within an individual (RI).
RE was evaluated when there were two or more VTs in one episode (that
is, ATP therapy was performed more than once in an episode). Of the VTs
classified on the basis of RR interval variability within an episode,
the ratio of the larger number of VTs by type (i.e., regular or
irregular) was defined as RE (Figure 1B). If the numbers of regular and
irregular VTs were identical in an episode, the episode was assigned
according to the variability of the first recorded VT in the episode.
RI was assessed in patients with multiple VT episodes. The ratio of the
larger number of VTs by type to the number of total VT episodes in all
episodes within an individual was defined as RI (Figure 2).