QT interval prolongation after oxytocin bolus during surgical induced abortion.
BACKGROUND
Although oxytocin, a uterotonic agent, may cause short-term vasodilation that results in severe hypotension, it is still routinely given as an intravenous bolus injection during surgical suction curettage. Two reported cases of ventricular tachycardia after oxytocin bolus in patients with long QT interval syndrome led us to assess the effect of oxytocin on QT interval.


METHODS
Thirty-eight healthy women scheduled for a surgical suction curettage with general anesthesia were enrolled. General anesthesia was induced by propofol and maintained by either propofol (n = 18) or sevoflurane (n = 20). Electrocardiographic recordings were obtained before and at 1, 2, 3, and 5 minutes after a 10-U intravenous bolus of oxytocin.


RESULTS
Intravenous oxytocin induced a pronounced QTc interval prolongation of 41 +/- 21 ms ( P < .0001), which was maximal 1 minute after administration. The QTc interval returned to control values 3 minutes after oxytocin bolus. Oxytocin bolus also induced an increase in heart rate of 19 +/- 10 beats/min and a significant decrease in systolic arterial pressure of 11 +/- 9 mm Hg (both P < .0001). The drug used to maintain anesthesia was not an independent factor of QT interval prolongation in ANOVA analysis.


CONCLUSIONS
Oxytocin intravenous bolus induced a large and transient QTc interval prolongation, suggesting that it may lead to proarrhythmia in circumstances favoring QTc interval increase.
Departent of Anesthesiology and Intensive Care, Beaujon University Hospital, Assistance Publique, Hôpitaux de Paris, Clichy, France. beny.charbit@bjn.ap-hop-paris.fr
Beny
B
Charbit
Christian
C
Funck-Brentano
Emmanuel
E
Samain
Virginie
V
Jannier-Guillou
Pierre
P
Albaladejo
Jean
J
Marty
D000028:Abortion, Induced; D000328:Adult; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008133:Long QT Syndrome / Q000139:chemically induced*; D010120:Oxytocics / Q000008:administration & dosage / Q000009:adverse effects*; D010121:Oxytocin / Q000008:administration & dosage / Q000009:adverse effects*; D011247:Pregnancy; D014619:Vacuum Curettage
D010120:Oxytocics; D010121:Oxytocin