Figure 2. Corrected QT interval and heart rate during sevoflurane anesthesia in a patient with idiopathic long QT syndrome. The left axis and diamonds represent QTc interval. The right axis and circles show heart rate at various times during the reported case. Administration of sevoflurane, 1.2% to 1.8%, is shown by the arrows and parallels an increase in QTc. The data points before sevoflurane inhalation represent, sequentially, administration of midazolam, institution of the lidocaine infusion, induction with propofol and fentanyl, relaxation with rocuronium, intubation, and inhalation of nitrous oxide. sevoflurane administration. Despite this, no extrasystoles appeared during sevoflurane administration. Blood pressure was stable at 100/50 mmHg throughout. Discontinuation of sevoflurane was followed by a return to shorter QTc intervals. A total of 6 ml bupivacaine, 0.25%, without epinephrine was injected into the extraction sites to provide analgesia. Emergence, including the effects of reversal of neuromuscular blockade with 2 mg intravenous neostigmine 0.3 mg intravenous glycopyrrolate, awakening, and extubation was associated with tachycardia and a rise in blood pressure to 130/75 mmHg, but no increase in QTc. As the patient awakened, single monoform extrasystoles appeared at the rate of 12/min. After extubation, multiform ventricular extrasystoles, as shown in panel D of Figure 2appeared at a rate of 39/min. Labetalol, 5 mg intravenously, was administered and the arrhythmia resolved. The labetalol effect probably reflects its antiadrenergic activity rather than a specific effect on QT prolongation. The heart rate and QTc after labetalol are shown by the last points in Figure 2. In the postanesthetic care unit, the lidocaine infusion was continued, but, 1 h later, multiform ventricular extrasystoles identical to those shown in panel D of Figure 1recurred. These responded to 5 mg intravenous labetalol and did not recur. Lidocaine was discontinued. After several hours of monitoring without further arrhythmias, the patient was discharged home where she continues to do well.

Figure 2. Corrected QT interval and heart rate during sevoflurane anesthesia in a patient with idiopathic long QT syndrome. The left axis and diamonds represent QTc interval. The right axis and circles show heart rate at various times during the reported case. Administration of sevoflurane, 1.2% to 1.8%, is shown by the arrows and parallels an increase in QTc. The data points before sevoflurane inhalation represent, sequentially, administration of midazolam, institution of the lidocaine infusion, induction with propofol and fentanyl, relaxation with rocuronium, intubation, and inhalation of nitrous oxide. sevoflurane administration. Despite this, no extrasystoles appeared during sevoflurane administration. Blood pressure was stable at 100/50 mmHg throughout. Discontinuation of sevoflurane was followed by a return to shorter QTc intervals. A total of 6 ml bupivacaine, 0.25%, without epinephrine was injected into the extraction sites to provide analgesia. Emergence, including the effects of reversal of neuromuscular blockade with 2 mg intravenous neostigmine 0.3 mg intravenous glycopyrrolate, awakening, and extubation was associated with tachycardia and a rise in blood pressure to 130/75 mmHg, but no increase in QTc. As the patient awakened, single monoform extrasystoles appeared at the rate of 12/min. After extubation, multiform ventricular extrasystoles, as shown in panel D of Figure 2appeared at a rate of 39/min. Labetalol, 5 mg intravenously, was administered and the arrhythmia resolved. The labetalol effect probably reflects its antiadrenergic activity rather than a specific effect on QT prolongation. The heart rate and QTc after labetalol are shown by the last points in Figure 2. In the postanesthetic care unit, the lidocaine infusion was continued, but, 1 h later, multiform ventricular extrasystoles identical to those shown in panel D of Figure 1recurred. These responded to 5 mg intravenous labetalol and did not recur. Lidocaine was discontinued. After several hours of monitoring without further arrhythmias, the patient was discharged home where she continues to do well.

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