Background and objectives: Some electrocardiographic algorithms have been developed to predict the location of the accessory pathway in the WPW syndrome. Few studies address the interobserver variability of such algorithms and the possible observer-dependent changes of accuracy. This study analyzes three algorithms to localize accessory pathways recently published, comparing the inter-observer variability, their predictive value and the most frequent problems observed during their application.
Methods: Ninety-six electrocardiograms from patients who underwent successful ablation of a single accessory pathway were reviewed. The location of each pathway was predicted by two independent observers according to three different reported electrocardiographic algorithms. The interobserver agreement, percentage of correct predictions and critical steps of each algorithm were analyzed.
Results: The interobserver agreement varied between 64 and 79% and the accuracy between 38 and 67%. The best results were obtained in the left lateral accessory pathways (69 to 89% correctly located). All the algorithms presented critical steps at which more than 20% of pathways were incorrectly classified.
Conclusions: The analyzed algorithms present a high interobserver variability. The accuracy obtained is clearly lower than that reported by the corresponding authors. These facts should be considered when being used them in clinical settings.