Torsades de pointes associated with inherited channelopathies

Torsades de pointes (TdP) arrhythmias are a hallmark of the inherited channelopathy known as the congenital long QT syndrome (cLQTS). The arrhythmia typically associates with a prolonged heart rate-corrected QT interval (QTc) and is usually preceded by a pause. Because pause-dependent arrhythmias are typical for LQTS type 2 (associated with genetic variants in the KCNH2 gene), the arrhythmia is most frequently seen in this subtype. Treatment consists of immediate elimination of potential triggers (most often particular drugs), supplementation of potassium and magnesium and attempts to avoid long RR intervals, for example, by pacing. A distinguished form of a “TdP-like” arrhythmia is preceded by short-coupled extrasystoles and is observed in patients with idiopathic ventricular fibrillation. For short-coupled TdP, acute treatment includes isoproterenol, while long-term prevention may include quinidine [in addition to an implantable cardioverter-defibrillator (ICD)]. Ablation of the initiating extrasystole, usually originating from the specialized conduction system, is another option.