Case Report

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There have been some case reports about propofol being antiarrhythmic [1-2]. Herein, after obtaining patient's informed and written consent, we want to share a case history wherein when delivery of baby with cesarean section happened immediately (within four minutes) after induction of general anesthesia with propofol, it was unclear whether it was induction of general anesthesia or delivery of baby that converted maternal atrial fibrillation into maternal sinus rhythm.

A 24-year-old and 63.3 kilogram-weighing primigravida patient presented for elective induction of labor at 40 weeks. She had no significant past medical or surgical or social or family history. She reported no allergies. One hour after trans-cervical Foley balloon insertion and inflation for mechanical induction of labor and immediately after receiving nalbuphine 10mg plus diphenhydramine 25mg intravenous bolus for pain control, fetal deceleration and maternal tachycardia were observed. Fetal deceleration resolved with maternal hands-and-knees position but maternal tachycardia with irregular pulse persisted. Twelve-lead electrocardiogram confirmed maternal atrial fibrillation with rapid ventricular rate response at 150s-160s. Patient denied any coexistent symptoms and her other vital signs were within normal limits. Patient was COVID-19 negative and had not received COVID-19 vaccination recently thus ruling out COVID-19 and its vaccination related cardiac changes [3]. Cardiology team was consulted and their team recommended metoprolol 2.5-5mg intravenous boluses (scheduled as well as on as-needed basis) to target heart rate at 120s-130s, maintenance of magnesium at >2mg/dL plus potassium at >4mmol/L, and delivery of baby in case of fetal distress. Transthoracic echocardiogram was within normal limits. Esmolol infusion for heart rate control, computed tomography chest to rule out pulmonary embolism, trans-esophageal echocardiogram to visualize cardiac valvular structures, cardioversion and anticoagulation were deferred for postpartum period pending urgent delivery of baby. Patient's heart rate did not respond to multiple intravenous doses of metoprolol. Urgent delivery of baby by cesarean section was planned. Considering her cardiac condition, it was debated whether slowly titrated epidural anesthesia or low dose spinal anesthesia should be utilized. Collaboratively, spinal anesthesia was decided but patient's persistent movement during attempts at spinal anesthesia led to abandonment of spinal anesthesia and pursuit of emergent general anesthesia for cesarean section. The thought to use etomidate for induction of general anesthesia considering maternal atrial fibrillation with rapid ventricular response was abandoned in favor of using propofol for induction of general anesthesia. General anesthesia was induced in rapid sequence with 150mg propofol (>2mg/kg) and 140mg succinylcholine (>2mg/kg) while maintaining cricoid pressure during GlideScope intubation of trachea. Phenylephrine 120mcg was given intravenously after tracheal intubation. Within four minutes, baby was surgically delivered and while placenta was being delivered surgically, normal sinus rhythm with normal heart rates at 100s was observed on the five-lead electrocardiogram on the anesthesia monitor. Patient vital signs remained stable intraoperatively and postoperatively. Postoperatively, twelve-lead electrocardiogram confirmed normal sinus rhythm with normal heart rates in 80s. Patient did not need transfer to intensive care unit for heart rate control with esmolol infusion under continuous and invasive arterial blood pressure monitoring. Trans-esophageal echocardiogram and cardioversion were not required. Computed tomography of chest ruled out pulmonary embolism. Subcutaneous heparin every eight hours was prophylactically initiated postoperatively. Intravenous metoprolol was converted to metoprolol 25mg by mouth twice a day. Additionally, patient received magnesium 4g and potassium 40mEq postoperatively. The patient was planned to follow up outpatient cardiology after discharge from postpartum floors.

This case highlights that if our team has had expected propofol to potentially convert atrial fibrillation to normal sinus rhythm, our team would have discussed the consideration of elective general anesthesia for the patient although it is still likely that our team might have pursued regional anesthesia considering its predictable safety profile for mother and neonate as compared to general anesthesia related inadvertent and unpredictable conversion of atrial fibrillation to sinus rhythm. Moreover, as the things were moving very fast from induction of anesthesia to intubation of trachea to delivery of baby, the five-lead electrocardiogram's rhythm was not specifically observed by our team to detect unexpected conversion of atrial fibrillation to sinus rhythm during the intervening four-minute time period wherein propofol in itself could have converted atrial fibrillation to sinus rhythm even before the intravenous dose of phenylephrine after intubation of trachea and thereafter much before the delivery of baby. Therefore, it was unclear whether it was induction of general anesthesia or delivery of baby that converted maternal atrial fibrillation into maternal sinus rhythm. However, considering the historically available medical literature about propofol, it can be certainly stated that propofol in itself contributed (even if not exclusively) towards conversion of maternal atrial fibrillation to normal sinus rhythm. Moreover, it remains unclear whether trans-cervical Foley balloon inflation or nalbuphine plus diphenhydramine combination caused persistent atrial fibrillation or whether it was induction of labor and corresponding pains in predisposed primigravida that led to atrial fibrillation [4-10] which got resolved with induction of anesthesia and thereafter delivery of baby. Anyhow, admission to intensive care unit and invasive trans-esophageal echocardiogram followed by traumatic electrical cardioversion were avoided by inadvertent resolution of atrial fibrillation with potential "chemical" cardioversion by anesthesia medications and potential "mechanical" or "physiological" cardioversion by delivery of baby. Interestingly, atrial fibrillation might have gotten started at the induction of labor pains and attempts at intravenous labor analgesia and gotten ended at the induction of general anesthesia and cesarean section delivery of baby.

References

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1. Cessation of Paroxysmal Atrial Fibrillation during Acute Intravenous Propofol Administration. https://pubs.asahq.org/anesthesiology/article/92/3/910/39699/Cessation-of-Paroxys mal-Atrial-Fibrillation-during
2. Propofol and arrhythmias: two sides of the coin. https://www.ncbi.nlm.nih.gov/pmc/articl es/PMC3505762/
3. Myocarditis and Pericarditis Following mRNA COVID-19 Vaccination. https://www.cdc.go v/coronavirus/2019-ncov/vaccines/safety/myocarditis.html
4. The Unexpected Pitter Patter: New-Onset Atrial Fibrillation in Pregnancy. https://www.hindawi.com/journals/criem/20 15/318645/
5. Onset of Lone Atrial Fibrillation During Labor Under Epidural Analgesia. https://www.ncbi.nlm.nih.gov/pmc/articl es/PMC3865834/
6. What Is a Foley Bulb Induction? https://ww w.verywellfamily.com/what-is-a-foley-catheter-induction-of-labor-2758962
7. Opioids/Nalbuphine Interactions. https://www.webmd.com/drugs/2/dru g-91727/cpm-pyrilamine-pe-hydrocodone-oral/details/list-interaction-details/dmid-2153/dmtitle-opioid s-nalbuphine/intrtype-drug
8. Opiates Raise AFib Risk, Make Heart Attacks More Likely. https://www.healthline.com/health-news/opiates-raise-atrial-fibrillation-r isk-makes-heart-attacks-more-likely-042715#1
9. Cardiovascular effects of nalbuphine in patients with coronary or valvular heart disease. https://pubmed.ncbi.nlm.nih.gov/6983316/
10. Non-sedating antihistamine drugs and cardiac arrhythmias – biased risk estimates from spontaneous reporting systems? https://www.ncbi.nlm.nih.gov/pmc/articl es/PMC1874280/

Source(s) of Funding

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Not Applicable

Competing Interests

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Not Applicable