Effect of spinal anesthesia on the QT interval in term and post-term pregnancies scheduled for elective cesarean section: a prospective study

Abstract Objectives: In this study, we aimed to investigate the effects of spinal anesthesia on the QT interval in patients with term and post-term pregnancy that were scheduled for elective cesarean section. Materials and methods: Forty pregnant women scheduled for elective cesarean section under spinal anesthesia were assigned into two groups: Post-term group (Group P) (n = 20) and Term group (Group T) (n = 20). After entering the operation room, standard monitoring [electrocardiography (ECG), noninvasive blood pressure, heart rate, respiratory rate, and peripheral oxygen saturation] was performed. The patient was placed in the sitting position and spinal anesthesia was performed with a median approach at the L3–L4a level using a 25G Quincke-type spinal needle. After cerebrospinal fluid was viewed, 12.5 mg (2.5 mL) hyperbaric bupivacaine was administered intrathecally over 1 min. Other ECG records were made at min 1 (T1), 5 (T2), and 10 (T3) after the induction of spinal anesthesia and after skin closure (T4). QT and QT dispersion were measured from ECG. Heart rate-corrected QT (QTc) and QT dispersion (QTcd) values were calculated using the Bazett formula. Results: Demographic characteristics of the patients were similar in both groups. Postoperative QTc, QTd, and QTcd values were significantly increased in Group P compared to those in Group T (p < .05). Conclusion: Spinal anesthesia led to increased postoperative QTc, QTd, and QTcd values in the patients with a gestational age of ≥42 weeks who underwent cesarean section. Accordingly, it is advisable to perform postoperative strict cardiac monitoring particularly in post-term pregnant women undergoing spinal anesthesia.