Effect of chronic arsenic exposure from drinking waters on the QT interval and transmural dispersion of repolarization.

This study investigated the effects of chronic arsenic exposure on QT- and QTc-interval prolongation, QTc dispersion (QTcd) and transmural dispersion of repolarization (TDR). We compared cardiac parameters from 40 male subjects chronically exposed to arsenic (group A) with those of 40 male subjects not exposed to arsenic (group B). Although subjects in both groups had non-corrected QT intervals within normal limits, subjects in group A had significantly longer QTc and QTcd intervals compared with group B. A total of 70% of group A compared with 10% of group B had QTcd values > 50 ms. The mean TDR value was also significantly higher in group A compared with group B. Although non-corrected QT intervals were within normal limits, those subjects chronically exposed to arsenic had a slight QT prolongation and a higher prevalence of subtle repolarization abnormalities, which might be clinically relevant.