In most cases, there are several predisposing causes, which may include: female sex, older age, hypokalemia, hypomagnesemia, hypothyroidism, slow ventricular rate, irregular ventricular rate, acute intracranial disasters (eg, bleeding, stroke, traumatic brain injury), eating disorders, organophosphate poisoning, and structural heart disease (especially acute ischemia, myocarditis, and ventricular hypertrophy).