Examples of acquired long QT syndrome. A common feature is a pause (often after an ectopic beat), indicated by a star, with deranged repolarization in the following cycle (red arrows). (A) Continuous recording from a 79-year-old man with advanced heart disease treated with the antiarrhythmic dofetilide. The abnormal QT interval is followed by 7 beats of polymorphic ventricular tachycardia (torsade de pointes). In this patient, torsade de pointes then precipitated sustained monomorphic ventricular tachycardia, due to underlying heart disease. (B) Torsade de pointes in a patient treated with the antipsychotic haloperidol. (C) Torsade de pointes in a patient with complete heart block. The blue arrows indicate nonconducted atrial depolarizations. (D) Markedly abnormal postpause repolarization in a patient with advanced heart failure. Such disordered repolarization may represent increased risk for torsade de pointes (7).