Isoproterenol hypokalemia with

Torsade de pointes polymorphous ventricular tachycardia associated with QT prolongation resulting from sotalol poisoning can be treated with isoproterenol infusion, magnesium, or overdrive pacing (see p 14). Correction of hypokalemia may also be useful. 

Many patients suffer from rhythm disturbances early after transplantation. Commonly they have a junctional rhythm until normal sinus activity reoccurs. Intravenous isoproterenol therapy early after transplantation can maintain the heart rate about 100-120 beats per minute, optimizing the cardiac output and preventing arrhythmias. Epicar-dial (atrio-)ventricular pacing is an alternative to pharmacological therapy. Asymptomatic, transient atrial arrhythmias are common with an incidence of about 20%-25% during hospital stay. Ventricular arrhythmias are more common than atrial arrhythmias (incidence up to 60%) and reflect the ischemic and reperfusion injury (prolonged ischemia time), hypokalemia or hypomagnesemia. 

---