Fetal tachyarrhythmias: current knowledge for clinical practice

Area of Science:

• Cardiology
• Fetal Medicine
• Neonatology

Background:

• Fetal arrhythmias represent a significant portion of specialized fetal medicine consultations.
• Tachyarrhythmias, a subset of fetal arrhythmias, pose risks including decompensation, hydrops fetalis, and fetal demise.
• Accurate diagnosis and timely intrauterine management are critical for improving fetal and postnatal outcomes.

Purpose of the Study:

• To describe the most common fetal tachycardias.
• To outline current intrauterine management strategies for fetal tachycardias.
• To provide insights into effective antiarrhythmic drug selection for various fetal tachyarrhythmias.

Main Methods:

• Fetal ultrasound and echocardiography are utilized to assess fetal heart rate, rhythm, and patterns.
• Diagnostic differentiation of fetal tachyarrhythmia types is essential for targeted treatment.
• Review of existing literature on fetal tachyarrhythmia diagnosis and management.

Main Results:

• Supraventricular tachycardia (SVT) treatment generally shows superior efficacy with flecainide and sotalol compared to digoxin, with combination therapy for hydrops.
• For sustained ventricular tachycardia (VT) with heart rates over 200 bpm, maternal intravenous magnesium is the first-line treatment.
• Frequency control is a key strategy for fetuses unresponsive to rhythm reversal and with pulmonary immaturity.

Conclusions:

• Effective intrauterine management of fetal tachycardias can significantly improve fetal and postnatal prognoses.
• Treatment selection for fetal tachyarrhythmias depends on arrhythmia type, clinical presentation, and healthcare team expertise.
• Transplacental therapy is the predominant route for administering antiarrhythmic medications in utero.