///2015 Abstract Details
2015 Abstract Details2019-08-02T16:54:43-06:00

Atrioventricular nodal reentrant tachycardia during a cesarean delivery

Abstract Number: T-30
Abstract Type: Case Report/Case Series

Jay Kothari MD1 ; Glen Atlas MD2; Antonio Gonzalez-Fiol MD3

Atrioventricular nodal reentrant tachycardia (AVNRT) is a type of tachycardia caused by a reentry circuit within, or near, the atrioventricular node. Typically the heart rate increases rapidly to 120 – 250 bpm. It is the most common type of paroxysmal supraventricular tachycardia (PSVT). It is also the most common arrhythmia in pregnancy.

A 30-year-old G2P1 woman with a history of palpitations presented to our institution at 39 weeks gestation for repeat cesarean delivery. Vital signs were BP 106/55, HR 64, temp 36.6°C, RR 20. Spinal anesthesia was planned for the surgery. Past medical and surgical history included an arrhythmia diagnosed intraoperatively during her previous cesarean delivery 5 years prior. The patient denied any recent palpitations or syncope during this pregnancy or needing to take any anti-arrhythmic medications. Her previous medical record revealed that after 10 ml of lidocaine 2% with epinephrine her EKG showed a narrow complex tachycardia. The fetal heart rate decreased to 100 bpm and an emergent cesarean delivery under general anesthesia was performed due to a patchy epidural. Cardiology was consulted intraoperatively and the patient was diagnosed with AVNRT, an esmolol drip was necessary to convert her arrhythmia to a sinus rhythm at 70 bpm. A postoperative EKG showed PACs with aberrant conduction. A TTE showed no abnormalities, and the patient was discharged on a β-blocker.

We considered the possibility of a positive test dose as the cause of her previous arrhythmia. Her current cesarean delivery was performed using a spinal anesthetic technique, consisting of bupivacaine 0.75% 1.5 ml, fentanyl 15 mcg, and morphine PF 150 mcg. Shortly after, the patient developed a heart rate in the 180s and EKG showed a narrow complex tachycardia. She was then given esmolol 10 mg IV, which broke the SVT and the heart rate returned to 80 bpm. During this episode the fetal heart rate was stable at 145 bpm. Cardiology was consulted, they recommended metoprolol XL 25 mg PO daily and follow up in cardiology clinic. The remainder of her hospitalization was uneventful. No cardiac abnormality was found.

PSVT occurs approximately at a rate of 2.6% in pregnant individuals; mostly AVNRT. (2) Our patient had an episode of AVNRT during each pregnancy after neuraxial anesthesia, but did not have any underlying cardiac pathology. The dilation of the cardiac chambers (which increases the length of a re-entrant circuit) and a decreased refractory period are some of the cardiovascular changes in pregnancy that can facilitate AVNRT. (3) Our patient might be particularly sensitive to those conduction changes of pregnancy. Fortunately, the majority of the arrhythmias occurring during pregnancy are non-lethal and they would resolve as these conduction changes return to their normal non-pregnant physiological state.

1 Robins K. Br J of Anaes. 92,140-3(2004)

2 Ob Anes & Uncmn Dis, 2e. 2008: 36.

3 Heart Disease in Pregnancy (Ch 16), 2e. Oakley

SOAP 2015