Effect of Spinal Anesthesia on QT Interval

Aim: This study aimed to compare the effect of spinal anesthesia on QT interval in severe pre-eclamptic and normotensive parturients who underwent cesarean section in a Nigerian tertiary hospital. Patients and Methods: Twelve-lead electrocardiogram (ECG) was obtained before, and at intervals after spinal anaesthesia on fifty severe pre-eclamptic (Group A) and fifty normotensive parturients (Group B) who underwent caesarean section. The effect of spinal anaesthesia on QT interval was compared. Results: The preoperative (baseline) mean QT interval was longer in group A than in group B; 453.10 ± 34.11 ms versus 399 ± 18.79 ms, P < 0.001. The prevalence of prolonged QT interval in the severe pre-eclamptic group before spinal anesthesia was 80% while in the normotensive group it was 0%, P < 0.001. At 5, 30, 60, and 120 min after the establishment of spinal anesthesia, the mean QT interval in the severe pre-eclamptic group was shortened and maintained within normal limits; 414.74 ± 28.05, 418.28 ± 30.95, 411.18 ± 19.21 and 401.36 ± 17.52 ms with P < 0.001 throughout. In the normotensive group, there was no significant change in the mean QT interval. Conclusions: This study demonstrated that the QT interval was more prolonged among the severe pre-eclamptic parturients. Spinal anesthesia using 0.5% hyperbaric bupivacaine normalized the QT interval and maintained it within normal limits during the study period.