A case report of a patient known to have long Q-T syndrome (LQTS) undergoing elective oral surgery is presented. While nitrous oxide-narcotic, nitrous oxideenflurane, or nitrous oxide-halothane techniques for anaesthetic management of LQTS have been previously reported, we report the use of nitrous o.tide-isoflurane for the maintenance of anaesthesia. The authors feel that isoflurane is a safe anaesthetic agent for use in LQTS.
Key wordsHEART: long Q-T syndrome, electrocardiography; ANAESTHETICS, VOLATILE: isoflurane; SURGERY: oral.Congenital long Q-T syndrome (LQTS) with syncopal episodes secondary, to ventricular tachyarrhythmias following emotional or physical stress has been described, l Ventricular tachyarrhythmias typically follow stimulation of the sympathetic nervous system secondary to stress, including the stress of anaesthesia and surgery. Indeed, unrecognized or improperly managed congenital LQTS may lead to intraoperative ventrieular tachyarrhythmias and even death?Although extensive medical literature on LQTS exists,~ descriptions of anaesthetic management are limited. Review of the literature indicates there have been only seven patients reported with this syndrome who have received anaesthesia? -7 These patients have been managed with nitrous oxideenflurane, nitrous oxide-halothane, and nitrous oxide-narcotic techniques. The following case is, to our knowledge, the first report of a palien! with LQTS anaesthetized with isoflurane.
Case reportA twenty-seven-year-old woman was scheduled for elective mandibular osteotomy. The diagnosis of LQTS was made three years prior to admission after the patient presented with a history of syncopal episodes since childhood. The patient had been well controlled on propranolol and diphenylhydantoin for three years. Three family members had LQTS with one death from the syndrome. There was no personal or family history of deafness. Electrocardiograms prior to admission documented long Q-T intervals with episodes of ventficular tachycardin. The patient's history was otherwise unremarkable. Physical examination on admission revealed a well-developed, well-nourished, white female in no acute distress. Heart rate was regular at 60 beats per minute with a blood pressure of !30/85 tort, respiratory rate was 16 per minute, and temperature was 36,7 ~ C. The patient was 5'8" tall and weighed 57 Kg. Examination of the heart, chest, abdomen, and CNS were within normal limits. Haemoglobin (hgb), haematocrit, blood urea nitrogen, serum creatinine, sodium (No), potassium (K), and calcium were within the normal range on admission. A standard 12 lead electrocardiogram (see Figure) showed a sinus bradycardia with a rate of 60 beats per minute. The Q-T interval was 0.44 s and there were prominent U waves.Hydromnrphone hydrochloride 0.5 mg, hydroxyzine hydrochloride 50mg, and glycopyrrolate 0.2 mg intramuscularly were given two hours prior to surgery. On arrival to the preoperative holding area, we instituted continuous electrocardiographic monitoring. Diazepam 10 mg and morphine sul...
