We present a case of a 65-year-old female admitted to the hospital due to severe intracranial hemorrhagia complicated by recurrences of polymorphic ventricular tachycardia of torsade de pointes type. ECG showed a marked prolongation of QT interval and giant U waves. The potassium level was 2.9 mmol/l and magnesium level - 0.6 mmol/l. Intravenous lidocaine and magnesium caused a complete supression of arrhythmia. Unfortunately, the patient died three days later due to cerebral damage and respiratory failure.