RCOG World Congress 2023

Focal Atrial Tachycardia in pregnancy: An Enigmatic challenge for the Obstetrician

Introduction

•Arises from a single site within either atrium

•Atrial activation starts rhythmically from a single area (focus), spreading centrifugally

•Arrhythmia arises from a smaller area; in contrast to classical macro-re-entry which involves multiple sites or forms circuit >2cm in diameter

•Incidence in pregnancy: 0.02-0.5%

Case Report

•23year, G4A3, 30 weeks gestation referred with chief complaint of Palpitations and shortness of breath on mild exertion since 4-5days (NYHA 3)

•ECG was suggestive of Ectopic Atrial Tachycardia.

•Screening 2D Echo- Moderate TR, mild MR, mild PAH with normal Left ventricular systolic function

Medical Management

•Patient was prepared for emergency pharmacological cardioversion. She responded to Diltiazem 90mg thrice daily along with Metoprolol 100mg twice daily dosing but only transiently.

•She was given the option of starting Flecainide (class IIIc anti-arrhythmic) Vs catheter ablation of ectopic focus under minimal fluoroscopy.

•The patient opted for Tab. Flecainide , which was started at 50mg twice daily dosing.

•Despite being on 3 anti-arrhythmic drugs, she had no relief. After thorough counselling with the patient, she was taken up for LSCS at 33weeks after steroid cover and delivered a healthy baby boy of 2kg.

Postoperative management

•Her heart rate continued to remain >=140/min, irregularly irregular, despite 3 anti-arrhythmics.

•However, after 72hours, her heart rate settled down to 86-92/min following which Flecainide was stopped.

•Both mother and baby were discharged in good condition on postoperative day8.

•Follow-up ECG done after a week showed resolution of Focal Atrial Tachycardia.

•Dose of metoprolol and diltiazem was titrated down and eventually stopped.

Discussion: Tachyarrhythmias in pregnancy are hypothesized to be due to increased sympathetic activity. The increase in plasma volume and heart rate leads to stretching of atrial and ventricular myocytes leading to activation of ion channels, resulting in arrhythmogenesis. It is often persistent and refractive to medical therapy. Usually it resolves after delivery. For acute treatment, adenosine should be used , as it is also diagnostic. Otherwise, beta-blockers, Calcium channel blockers or digoxin can be used for rate control. If these agents fail, sotalol or flecainide may be considered. Focal Atrial Tachycardia can be associated with tachycardia induced cardiomyopathy. Use of flecainide is a reasonable therapeutic option for the treatment of malignant pre-excited tachycardia. It should be preferred over ablation in low-volume centres.

Conclusion: Management of tachyarrhythmia depends on the presence of underlying structural heart disease and includes specific anti-arrhythmic drugs with safety data during pregnancy. Treatment of choice is catheter ablation of ectopic focus under minimal/zero fluoroscopy. Therefore a multidisciplinary and stepwise approach is of paramount importance.

References:

1.Enriquez AD, Economy KE, Tedrow UB. Contemporary management of arrhythmias during pregnancy. Circ Arrhythm Electrophysiol. 2014;7(5):961-7

2.Chauveau S, Le Vavasseur O, Morel E, Dulac A, Chevalier P. Flecainide is a safe and effective treatment for pre-excited atrial fibrillation rapidly conducted to the ventricle in pregnant women: a case series. Eur Heart J Case Rep. 2019;3(2)

3.Wang NC, Shen C, McLaughlin TJ, et al. Maternal focal atrial tachycardia during pregnancy: A systematic review. J Cardiovasc Electrophysiol. 2020;1-16

4.Santos JG, Briosa A, Sebaiti D, Almeida S, et al. One ominous case of focal atrial tachycardia in pregnancy, two victims and a successful outcome: a case report. Int J Arrhythm. 2022;23(1)

RCOG World Congress 2023

Focal Atrial Tachycardia in pregnancy - An Enigmatic challenge for the Obstetrician

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