Assessment of the unipolar and bipolar electrograms on the
mapping module
All unipolar electrograms were assessed automatically by the CARTOFINDER
algorithm as follows. The window
of interest (WOI) was determined based on the total activation phase of
the bipolar electrogram, and annotation points were assigned to the
maximum negative slope of the unipolar electrogram within each WOI.
Every cycle length (CL) was measured from each local activation interval
during the entire recording period, and the mean CL and CL standard
deviation (CLSD) for each channel were calculated (Fig. 1A). Among all
CL measurements collected from the 20 electrodes of the PentaRay
catheter at each recording site, the most frequent value of CL was
considered the DCL (Fig. 1B). Focal activations were defined as ≥ 2
consecutive QS patterns on the unipolar electrogram registered ≤ 50 ms
earlier than the proximal electrodes located within a 10-mm radius (Fig.
1C) and were visually displayed as a 3-dimensional map (CARTOFINDER
map), along with the CL, CLSD, and the number of repetitions of focal
activations (focal intensity).
The bipolar electrograms were recorded simultaneously during CARTOFINDER
mapping (Fig. 2). The maximal bipolar voltage and electrogram
morphologies were evaluated at sites of focal activation. Bipolar
electrogram morphologies were divided into the following three
categories based on the presence or absence of an isoelectric line: (1)
discrete type, (2) fractionated type, and (3) combination
type.14 The combination type involved both types of
discrete and fractionated electrograms during the simultaneous recording
period. The discrete type was further divided based on the electrical
potential components: single potentials characterized by single
deflection and non-single potentials.