Abbreviation: TdP
A polymorphic ventricular tachycardia with a shifting ECG axis that is triggered by early afterdepolarizations of the left ventricle in patients with a prolonged QTc interval. Associated with electrolyte abnormalities (hypokalemia, hypomagnesemia), certain drugs, and congenital heart disease. It often reverts spontaneously to sinus rhythm but a life-threatening ventricular fibrillation may sometimes develop.