The risk of torsades de pointes in patients on sotalol is increased in the setting of renal failure. QT dispersion and prolonged QT intervals have been described as markers for pro-arrhythmia. Four cases of torsades de pointes caused by low dose sotalol in patients with renal failure are reported. All four cases demonstrated that the 12-lead electrocardiogram, with markedly prolonged QT intervals and increased QT dispersion, could have been used to predict pro-arrhythmia.