All cases of arrhythmias associated with thioridazine were reviewed (177 cases). No case of severe ventricular arrhythmia was reported in children. In adults, at therapeutic doses, ventricular tachycardia or fibrillation (VT/VF) or torsade de pointes was observed mainly in patients with concomitant risk factors. At doses higher than 800 mg, atrioventricular (A-V) and bundle branch blocks were associated with VT/VF. Mortality was higher in patients with A-V blocks. Although transient cardiac pacing is known to be efficacious to control phenothiazine-induced arrhythmias, it was rarely used.