Hemodynamics in fetal arrhythmia

Abstract

Fetal arrhythmias are among the few conditions that can be managed in utero. However, accurate diagnosis is essential for appropriate management. Ultrasound-based imaging methods can be used to study fetal heart structure and function noninvasively and help to understand fetal cardiovascular pathophysiology, and they remain the mainstay of evaluating fetuses with arrhythmias in clinical settings. Hemodynamic evaluation using Doppler echocardiography allows the elucidation of the electrophysiological mechanism and helps to make an accurate diagnosis. It can also be used as a tool to understand fetal cardiac pathophysiology, for assessing fetal condition and monitoring the effect of antiarrhythmic treatment. This narrative review describes Doppler techniques that are useful for evaluating fetal cardiac rhythms to refine diagnosis and provides an overview of hemodynamic changes observed in different types of fetal arrhythmia.

Reference Ranges for Fetal Atrioventricular and Ventriculoatrial Time Intervals and Their Ratios during Normal Pregnancy

“…Our results demonstrate that under physiological conditions, the VA time is about 2-5 times longer that the corresponding AV time. Re-entry tachycardias typically present with a VA time that is shorter than the AV time because a fast conducting accessory connection directs the electrical impulse from the ventricle back to the atria, and the AV:VA ratio will therefore increase to >1.0 [20]. While all other supraventricular fetal tachyarrhythmias are summarised as long VA tachyarrhythmias, it will be interesting in further studies to see whether the AV:VA ratio varies according to the underlying pathology, and to test the use of our reference ranges in that setting.…”

Maternal steroid therapy for fetuses with second‐degree immune‐mediated congenital atrioventricular block: a systematic review and meta‐analysis

“…Prenatal diagnosis of second‐degree AVB was done in the presence of a progressive lengthening of AV conduction, until an isolated impulse was blocked (Mobitz I) or, in the case of a sudden block of an isolated impulse, without prior lengthening of the AV conduction time (Mobitz II). Finally, third‐degree AVB was diagnosed when there was no AV conduction , with the atria and ventricles beating independently .…”

“…Congenital atrioventricular block (AVB) encompasses a wide spectrum of conditions characterized by the interruption of the conduction of electrical impulses from the atria to the ventricles . First‐degree AVB is characterized by a prolonged atrioventricular (AV) interval, whereas in second‐degree ABV, some beats are conducted and others are blocked.…”

“…First‐degree AVB is characterized by a prolonged atrioventricular (AV) interval, whereas in second‐degree ABV, some beats are conducted and others are blocked. In third‐degree AVB, there is complete interruption of AV conduction so that atria and ventricles beat independently . AVB can occur in fetuses with congenital heart disease; however, when isolated it is commonly associated with maternal autoantibodies, especially SSA/Ro and SSB/La .…”

“…Early gestational age at diagnosis, low ventricular rate and the presence of fetal hydrops have been reported to be the major determinants of perinatal outcome in fetuses affected by immune‐mediated AVB . Despite this, optimal management once AVB has been detected in utero has yet to be established .…”