///2014 Abstract Details
2014 Abstract Details2019-07-18T14:34:47-06:00

New-Onset Atrial Fibrillation Complicating Labor in a Healthy Parturient

Abstract Number: S-40
Abstract Type: Case Report/Case Series

Jessica Rock M.D.1

Case:

An otherwise healthy, 23-year-old G1P0 presented at 38 weeks gestational age complaining of ruptured membranes and palpitations beginning 3 hours prior to admission. She was contracting regularly. Blood pressures were 120s/70s, but the radial pulse was fast and irregularly irregular. SpO2 was 98% on room air, and temperature 36.7˚ C. She denied angina, dyspnea, or pre-syncopal symptoms. Twelve-lead ECG showed atrial fibrillation with HR 180-200 bpm, and no evidence of Wolf-Parkinson-White Syndrome. Esmolol had no effect. The patient was found to be in labor and 4 cm dilated. She requested analgesia. As FHT was reassuring, the decision was made to provide epidural analgesia.

A lumbar epidural catheter was placed and, after a negative test dose, 10 mL of bupivacaine 0.125% was given in divided doses over ten minutes, with good analgesic effect. Maternal cardiac rhythm and rate did not change, but the automated BP machine failed to provide values, and the FHT exhibited decelerations with contractions. The patient continued to deny other symptoms. Her cervix was found to be 10 cm dilated with the fetal head at +2 station. As the FHT continued to return to baseline between contractions, the decision was made to proceed with forceps-assisted vaginal delivery. IV esmolol, metoprolol, and phenylephrine were given prior to and during pushing, with no effect on maternal or fetal HR. Maternal BP was 85/50 and maternal HR during second stage was 180s-210s; the patient continued to deny symptoms. Delivery of a live infant, Apgars 8 and 9, occurred just under two hours after admission. After delivery, the ventricular rate decreased to 110s-150s after administration of diltiazem, and the BP increased to 110s/60s. Chest CT was negative for PE; an aberrant pulmonary vein was seen arising from the LA. Echo showed normal biventricular size and function and biatrial enlargement consistent with pregnancy. CBC, CMP, and TSH were all normal. The patient continued on diltiazem; digoxin and metoprolol were added per cardiology. She spontaneously converted to sinus rhythm 11 hours after delivery.

Discussion:

Although pregnancy may predispose to cardiac dysrhythmias(1), lone atrial fibrillation in otherwise healthy parturients is very rare; most cases are explained by abnormal cardiac anatomy, drugs, electrolyte derangements, or PE(2). Treatment consists of rate control and, if necessary, anticoagulation and/or cardioversion. In this case, the rapid progress of labor and lack of response to β-blocking agents complicated treatment. This appears to be the first report of lone atrial fibrillation concurrent with onset of labor; however, it is possible that this patient was predisposed to atrial arrhythmias due to her aberrant pulmonary vein.

1. Cacciotti L, Camastra GS, Ansalone G. Atrial fibrillation in a pregnant woman with a normal heart. Intern 2010;5:87-8.

2. DiCarlo-Meacham A, Dahlke J. Atrial fibrillation in pregnancy. Obstetrics & Gynecology 2011;117:489-92

SOAP 2014