A cardiac CHANNELOPATHY and arrhythmia associated with a predisposition to ATRIAL FIBRILLATION and SUDDEN CARDIAC DEATH. Patients have a structurally normal heart, but electrocardiography (ECG) exhibits abbreviated QTc (Bazett's corrected QT) intervals of less than 360 ms. May be caused by autosomal dominant mutations in the KCNH2 gene. OMIM: 609620
