Flumazenil is innocuous in a paroxysmal supraventricular tachycardia and radiofrequency ablation: a paediatric case report and review of the literature

The efficacy and safety of flumazenil in reversing midazolam-induced paradoxical reaction in a child suffering from paroxysmal supraventricular tachycardia (PSVT) and undergoing radiofrequency ablation procedure has not been described before. We report a boy who had suffered for years from poorly controlled PSVT because of noncompliance to medications and was being sedated by midazolam and morphine (4 mg each) and prepared for radiofrequency ablation when he began attempting to speak, writhing and flailing his arms, for which physical restraint was required. We also review the current knowledge on the subject. Two doses of flumazenil 0.05 mg i.v. swiftly halted the untoward episode. The child opened his eyes and was calm, coherent and able to answer simple questions. All haemodynamic and respiratory parameters remained stable throughout this event, except for a temporary increase in heart rate (from 68 to 83 b x min-1). The aberrant behaviour did not resume when he was allowed to fall asleep during the ablation of a concealed left lateral accessory pathway. After that procedure, he awoke calm and pain free with no recollection of the aggressive episode. He was kept for 24 h in an intermediate cardiac care unit and was then discharged home. This apparent first report on the efficacious use of flumazenil for the reversal of a paradoxical reaction to midazolam during an electrophysiological study suggests that it neither induces abnormal heart rate nor interferes with the electrophysiological study or the ablation procedure.