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Postnatal management of fetal arrhythmias

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To ensure a seamless transition from fetal to postnatal life of babies receiving a prenatal diagnosis of an arrhythmia.


This guideline is for neonatologists and paediatric cardiology teams, caring for babies with a prenatal diagnosis of a fetal arrhythmia.

Fetal arrhythmias are uncommon and the incidence of structural cardiac abnormalities in fetuses with irregular heart rhythms is low (<2%). Ectopic beats are estimated to be present in around 1% of unselected pregnancies and in the majority of cases will resolve before delivery.

Fetal tachycardia can result in significant morbidity and mortality if left untreated in utero. The ideal management is to treat the tachycardia prior to delivery so that the fetus is delivered in a non-hydropic state, at term, without evidence of tachycardia. Prenatal therapy is guided by the fetal cardiology and fetal medicine team jointly and in our institution 1st line maternal therapy is often flecainide. The addition of second line therapy is required in resistant cases. Therapy is carefully considered, implemented and monitored due to the potential adverse effects to the mother and fetus.

1. Fetal Irregular Heart Rhythm

a) If extrasystoles persist after birth

  • Remain on PNW for 48 hours before discharge home
  • 12 lead ECG
    • Mon-Fri 9-5pm arrange with cardiology department (84437), out of hours/weekend to be undertaken by the neonatal team
  • Auscultate HR for 1 minute
    • If ectopic every 10 beats - discuss with cardiology oncall (84440) whether a 24 hour ECG is required
    • If less frequent, no further investigations required but the baby should remain on PNW until 48 hrs old
  • Discuss 24 hour ECG with cardiology consultant and arrange f/u as required
  • If ventricular extra-systoles (VEs) on ECG, discuss with cardiology consultant or oncall cardiology registrar (84440)

b) If extra-systoles have resolved prior to birth

  • No postnatal follow-up or investigation is indicated.
2. Fetal Tachycardia

a) Failure to cardiovert medically during fetal life

  • Admit to NICU
  • Inform on call cardiology consultant or cardiology registrar (84440) immediately
  • Continuous ECG monitoring
  • Baseline echocardiogram and 12 lead ECG
  • Medical therapy/cardioversion as per on call cardiologist advice

b) Successful medical cardioversion during fetal life

  • Admit to NICU for 48 hours before transfer to PNW.
  • NEWS observations to be undertaken on PNW for 48 hours before discharge home.
  • Request cardiology consult (84440) within normal working hours if in sinus rhythm and cardiovascularly stable
  • Baseline echocardiogram and 12 lead ECG
  • Ensure parents are taught and competent at checking the heart rate by measuring the pulse/listening with stethoscope or ear.
  • Families will be provided with an information leaflet before discharge home, detailing monitoring and measuring heart rate – cardiac nurse specialists will provide leaflet.
  • Parents should assess the heart rate at least twice daily when baby settled.
  • Cardiac Nurse Specialists will discuss the additional benefits of an OwletTM monitor if parents wish to purchase for additional reassurance.
  • On discharge, parental advice to seek urgent medical attention if evidence of poor feeding, or tachycardia i.e. >180bpm when baby settled.
  • Provide contact details for the cardiac nurse specialists for non urgent support between outpatient clinics: (0141 452 4925)
  • Arrange Cardiology OPC for 2 weeks post discharge.

  • If tachycardia recurs before discharge, therapy and f/u as per on call cardiologist advice
  1. FAST Trial – Fetal Atrial Flutter and Supraventricular Tachycardia Trial. Multicentre, international registry and RCT. Jeaggi et al, Toronto Sick Kids Hospital, Toronto, Canada.
  2. Jaeggi E, Ohman A. Fetal and Neonatal Arrhythmias. Clin Perinatol. 2016 Mar;43(1):99-112.
  3. Simpson J, Silverman N. Diagnosis of cardiac arrhythmias during fetal life. In: Gembruch U, editor. Fetal Cardiology. London: Martin Dunitz; 2003. p. 333-344.
  4. Vergani P, Mariani E, Ciriello E, Locatelli A, Strobelt N, Galli M, Ghidini A. Fetal arrhythmias: natural history and management. Ultrasound med Bio 2005 Jan;31(1):1-6
  5. Van Engelen AD, Weijtens O, Brenner JI, Kleinman CS, Copel JA, Stoutenbeek P, et al. Management outcome and follow-up of fetal tachycardia. J Am Coll Cardiol 1994;24(5):1371-5.
  6. Simpson JM, Sharland GK. Fetal tachycardias: management and outcome of 127 consecutive cases. Heart 1998;79(6):576-81.
  7. Frohn-Mulder IM, Stewart PA, Witsenburg M, Den Hollander NS, Wladimiroff JW, Hess J. The efficacy of flecainide versus digoxin in the management of fetal supraventricular tachycardia. Prenat Diagn 1995; 15(13):1297-302.
  8. Echt DS, Liebson PR, Mitchell LB, Peters RW, Obias-Manno D, Barker AH, et al. Mortality and morbidity in patients receiving encainide, flecainide, or placebo. The Cardiac Arrhythmia Suppression Trial. N Engl J Med 1991;324(12):781-8.
  9. Fouron JC. Fetal arrhythmias: the Saint-Justine hospital experience. Prenat Diagn 2004;24(13):1068-80.
Editorial Information

Last reviewed: 03 May 2023

Next review: 31 May 2025

Author(s): Dr Lindsey Hunter; Dr Karen McLeod; Lorraine Mulholland; Kathleen O’Reilly; Dr Andrew MacLaren

Version: 1

Approved By: Paediatric Cardiology & Neonatology

Reviewer Name(s): A Powls; M Worrall; G Bell

Document Id: 1081