This 88-year-old man with a history of hypertension and diabetes was admitted to hospital for treatment of congestive heart failure. He had been on sotalol 80 mg po bid for the past year due to previous episodes of paroxysmal atrial fibrillation. The following ECG was recorded on admission: 

•  Sinus rhythm, 60/min
•  Left axis deviation
•  Non-specific ST abnormality
•  Long QT (QT/QTc  488/488 msec)

Sotalol prolongs the action potential duration of the myocardium and the QT

One day after admission, his cardiac monitor showed the occurrence of an arrhythmia, not associated with any symptoms:

• Sinus rhythm with premature ventricular complexes and a 2.2 sec. episode of non-sustained polymorphic ventricular tachycardia (torsade de pointes)
• Ventricular rate 98/min
• Long QT 

There were no serum electrolyte abnormalities. As sotalol may induce torsade de points, the drug was stopped. No further arrhythmias occurred, and the patient was discharged four days later after successful diuresis: