Background: The etiology of accessory pathway (AP) formation is generally unknown.
Objective: The purpose of this study was to test the hypothesis that AP formation is genetically mediated by examining whether AP location differs by sex and/or race, using sex and race as proxies to distinguish genetically different individuals.
Methods: This was a single-center, retrospective cohort study of 282 consecutive patients undergoing their first electrophysiology study that revealed at least one AP between 2004 and 2008. Sex and race were compared with AP location determined by invasive electrophysiology study.
Results: Eighty-nine (52%) males and 40 (36%) females had a left posterior AP (P = .006). Sixty-four (57%) females had a right annular AP, compared with 55 (32%) males (P <.001). After adjusting for age and race, females had 2.8-fold greater odds of having a right annular AP compared with males (95% confidence interval [CI] 1.70-4.65 greater odds; P <.001). While right anterior (free-wall) pathways were rare in all other races (12%), a significantly larger proportion of Asians (n = 10, 26%) had a right anterior AP (P = .017). After adjusting for sex and age, Asians had 3.8-fold greater odds of having a right anterior AP compared with other races (95% CI 1.5-9.4 greater odds; P = .004).
Conclusions: Females more commonly had right annular APs, and Asians had right anterior APs substantially more frequently than other races. These findings suggest that the pathogenesis of AP formation may have a genetic component.