"Les torsades de pointes": an unusual ventricular arrhythmia.

Since the original description by Dessertenne, predominantly European literature has reported the features of the unusual ventricular arrhythmia "les torsades de pointes." Named because of the way the polarity of the QRS complexes seems to spiral around the baseline of the ECG, this arrhythmia is virtually always associated with prolongation of the Q-T interval. Its importance lies not in its unusual structure but in the potentially fatal outcome if conventional treatment is administered. Antiarrhythmic drugs that further prolong the Q-T interval frequently aggravate the arrhythmia and are contraindicated. Overdrive pacing, preferably atrial, is the treatment of choice with attention to any correctable causes of associated Q-T prolongation. Electrophysiologic studies so far favor a re-entrant cause for the arrhythmia, but the exact mechanism and its true relation to both conventional ventricular tachycardia and ventricular fibrillation remain to be defined.