SCN5A and overlapping connective tissue disease: LQTS patients show lower ages of onset for AF, typically at age 50±14 years.33, 34 LQTS, particularly LQTS3, patients show increased risks of life‐threatening ventricular arrhythmias after 40 years of age that are influenced by particular specific factors, such as gender and clinical history.12, 35 LQTS3 patients can also show long‐term changes normally associated with Nav1.5 haplo‐insufficiency resulting in overlap syndromes that combine both loss (BrS) and Nav1.5 gain‐of‐function (LQTS3) phenotypes.