Potassium Channel Block and Novel Autoimmune-Associated Long QT Syndrome.

This article reviews advances in the pathogenesis of anti-SSA/Ro antibody-induced corrected QT (QTc) prolongation in patients with autoimmune diseases; particularly connective tissue disease (CTD). Evidence shows that anti-SSA/Ro antibody-positive patients with CTD show QTc prolongation and complex ventricular arrhythmias. Molecular and functional data provide evidence that the human ether-a-go-go-related gene potassium channel conducting the rapidly activating delayed rectifier potassium current is directly inhibited by anti-SSA/Ro antibodies, resulting in action potential duration prolongation leading to QT interval lengthening. Routine electrocardiogram screening in anti-SSA/Ro antibody-positive patients and counseling for patients with other QTc prolonging risk factors is recommended.