How to manage atrial fibrillation (AF) in pregnancy?

Management of Atrial Fibrillation During Pregnancy

Immediate electrical cardioversion is recommended in pregnant patients with AF who are hemodynamically unstable or have pre-excited AF to improve maternal and fetal outcomes. 1

Initial Assessment and Multidisciplinary Approach

• AF during pregnancy is associated with increased risk of death and requires prompt evaluation 1
• A multidisciplinary team approach is essential, including:
  • Cardiologists experienced in pregnancy
  • Gynecologists
  • Neonatologists
  • Maternal medicine specialists
  • Anesthesiologists 1

Rate vs. Rhythm Control Strategy

Hemodynamically Unstable Patients

• First-line: Immediate electrical cardioversion 1
  • Safe at all stages of pregnancy
  • Monitor fetal heart rate throughout and after cardioversion
  • Precede with anticoagulation when appropriate

Hemodynamically Stable Patients

Rate Control

• First-line: Beta-1 selective blockers 1, 2

  • Avoid atenolol (associated with intrauterine growth restriction)
  • Metoprolol is preferred due to safety record 2

• Second-line: Digoxin 1

  • Consider when beta-blockers are ineffective or contraindicated

• Alternative: Non-dihydropyridine calcium channel antagonists (verapamil, diltiazem) 1

  • Can be used if beta-blockers are contraindicated

Rhythm Control

• For persistent AF: Consider electrical cardioversion 1

  • Especially important in women with hypertrophic cardiomyopathy

• For pharmacological cardioversion in stable patients with structurally normal hearts:

  • Intravenous ibutilide or flecainide may be considered 1
  • Experience is limited with these agents during pregnancy

• For longer-term rhythm control:

  • Flecainide or propafenone may be considered when rate control drugs are ineffective 1
  • Avoid amiodarone if possible due to fetal risks 3

Anticoagulation Management

• Pregnancy creates a hypercoagulable state with increased thromboembolism risk 1
• Use standard risk assessment tools (CHA₂DS₂-VASc) as in non-pregnant women 1

Anticoagulation Recommendations:

• First trimester and after week 36: Low molecular weight heparin (LMWH) 1

  • Does not cross placenta
  • Frequent monitoring (every 10-14 days) and dose adjustments in third trimester

• Second trimester through week 36: Vitamin K antagonists (VKAs) 1

  • Avoid in first trimester (risk of miscarriage, teratogenicity)
  • Avoid after week 36 (risk of fetal intracranial bleeding)

• Direct oral anticoagulants (DOACs): Not recommended during pregnancy 1

Special Considerations

• Vaginal delivery: Recommended for most women 1

  • Contraindicated during VKA treatment due to risk of fetal intracranial bleeding

• Catheter ablation: Generally avoided during pregnancy 1

  • May be considered in refractory cases using zero-fluoroscopy techniques

• Women with mechanical heart valves: Require special consideration

  • May need continuous IV unfractionated heparin or dose-adjusted LMWH between weeks 6-12 1

Monitoring and Follow-up

• Close monitoring of anticoagulation levels, especially in third trimester
• Regular assessment of maternal and fetal well-being
• Continuous evaluation of treatment efficacy and side effects

Pitfalls and Caveats

• Avoid atenolol due to association with intrauterine growth restriction 1, 2
• VKAs are teratogenic in first trimester and increase risk of fetal hemorrhage in later stages 1
• Amiodarone should be avoided due to potential for congenital abnormalities 3, 4
• DOACs have limited safety data in pregnancy and should be avoided 1, 3
• Recognize that higher doses of anticoagulants may be needed during pregnancy due to physiological changes 1