Overview
Fetal tachycardia refers to an abnormally fast heart rate in the fetus, often indicative of underlying cardiac or systemic conditions. It can manifest as ventricular or supraventricular tachycardia and may be associated with hydrops fetalis or other fetal distress syndromes 4.Diagnosis
Electrocardiogram (ECG): Essential for identifying tachycardia type (wide vs narrow QRS) and assessing variability 1.
Echocardiography: Crucial for visualizing cardiac structure and function, particularly in diagnosing fetal ventricular tachycardia 4.
Differential Diagnosis: Consider AV nodal reentrant tachycardia (AVNRT) with variable AV relationships, which can mimic atrial tachycardia 2.Management
First-line Treatments:
- Cardioversion: Considered for symptomatic cases; quinidine was attempted but unsuccessful in one fetal case 4.
Adjunctive Treatments:
- Procedural Sedation for Cardioversion: Propofol, methohexital, thiopentone, and etomidate are recommended for sedation during cardioversion procedures 3.Special Populations
Pregnancy: Fetal ventricular tachycardia can occur with nonimmunologic hydrops fetalis; cardioversion attempts may be limited by fetal safety concerns 4.Key Recommendations
Utilize echocardiography for definitive diagnosis of fetal tachycardia, particularly to differentiate ventricular from supraventricular origins 4.
Consider procedural sedation with propofol, methohexital, thiopentone, or etomidate for cardioversion in critically ill neonates or fetuses requiring intervention 3.
Approach irregular AVNRT with caution due to potential misdiagnosis as atrial tachycardia; electrophysiological studies may be necessary for accurate classification 2 (Evidence: Moderate).References
1 Firsovaite V, Duytschaever M, Tavernier R. From a wide to a narrow QRS tachycardia and back. What is the mechanism?. Acta cardiologica 2012. link
2 Otomo K, Nagata Y, Uno K, Fujiwara H, Iesaka Y. Irregular atypical atrioventricular nodal reentrant tachycardia: incidence, electrophysiological characteristics, and effects of slow pathway ablation. Heart rhythm 2007. link
3 Wood J, Ferguson C. Best evidence topic report. Procedural sedation for cardioversion. Emergency medicine journal : EMJ 2006. link
4 Sherer DM, Sadovksy E, Menashe M, Mordel N, Rein AJ. Fetal ventricular tachycardia associated with nonimmunologic hydrops fetalis. A case report. The Journal of reproductive medicine 1990. link