Influence of pregnancy on the risk for cardiac events in patients with hereditary long QT syndrome

Background —The effects of pregnancy on women with the hereditary long QT syndrome are currently unknown. The appropriate medical management of pregnant patients with the long QT syndrome has not been established. Methods and Results —The study was a retrospective analysis of the 422 women (111 probands affected with the long QT syndrome and 311 first-degree relatives) enrolled in the long QT syndrome registry who had one or more pregnancies. The first-degree relatives were classified as affected (QTc >0.47), borderline (QTc=0.45 to 0.47), and unaffected (QTc