Ventricular tachyarrhythmias in the long QT syndromes.

Marked prolongation of the electrocardiographic QT interval often is associated with a distinctive form of ventricular tachycardia characterized by the gradual oscillation around the baseline of the peaks of successive QRS complexes. This was named torsades de pointes, or "twisting of the points." This form of ventricular tachycardia tends to be rapid and self-terminating and often occurs in clusters, leading afflicted patients to present with recurrent dizziness and syncope. Ventricular fibrillation and sudden death are common.