Exploratory and validation phases
The first 546 consecutive patients provided dataset of AP localization
and QRS morphology types in 12 leads including 509 ECGs with full
preexcitation and 547 ECGs with baseline preexcitation that were
furnished to the WPW24.com database. Distribution of all APs in that
cohort is presented in Figure 1 and Table 1 .
Illustrative examples of how QRS polarity in a single ECG lead impacts
distribution of APs along mitral and tricuspid annuli is presented inFigure 5 and 6 . Depending on the AP type/localization there
were 2 to 5 optimized steps for ECG analysis. To reach the
final diagnosis/distribution map a mean 3.0 +/-steps per ECG were
needed.
For validation, the dataset of 260 ECGs were used, 49% of these ECGs
were obtained prospectively, after the exploratory phase. The remaining
51% were obtained retrospectively albeit from a new centre that did not
participate in the exploratory phase. Distribution of all APs in the
exploratory and validation phases is presented in Figure 1 andTable 1 – no differences in the distribution of APs between
the exploratory and validation datasets were found (p = 0.263).
To compare the exploratory cohort with the data from the literature a
simplified categorization of AP regions had to be applied since the
categorization and regions in every study are different, sometimes
poorly defined and often with overlap of different regions among
studies, making direct detailed comparison impossible
(Supplementary Table 1 ). However, when all AP were grouped into
four major categories (right free wall, left free wall, right
posteroseptal and other septal) no difference in the distribution of AP
among the exploratory cohort and the pooled cohort from the seven
published studies (n = 1252), was present, p = 0.24.