An uncommon form of tachycardia characterized by beat-to-beat alternation of the morphology and the axis of the QRS complexes seen in some of the ELECTROCARDIOGRAM leads. The usual ventricular rate ranges from 140 to 180 bpm and can be regular or irregular. It is usually associated with DIGITALIS toxicity, but may occur in cases of HYPERKALEMIC PERIODIC PARALYSIS; HYPOKALEMIC PERIODIC PARALYSIS; BRUGADA SYNDROME; and severe structural heart disease. (Anesth Analg. 2002 Aug;95(2):310-5)
