Fetal arrhythmias: prenatal evaluation and intrauterine therapeutics

Abstract

Introduction: Fetal arrhythmias are a common phenomenon with rather complicated etiologies. Debates remain regarding prenatal diagnosis and treatment of fetal arrhythmias. Methods:The literature reporting on prenatal diagnosis and treatment of fetal arrhythmias published in the recent two decades were retrieved, collected and analyzed. Results: Both fetal magnetocardiogram and electrocardiogram provide information of cardiac time intervals, including the QRS and QT durations. M-mode ultrasound detects the AV and VA intervals, fetal heart rate, and AV conduction. By using Doppler ultrasound, simultaneous recording of the atrial and ventricular waves can be obtained. Benign fetal arrhythmias, including premature contractions and sinus tachycardia, do not need any treatment before and after birth. Sustained fetal arrhythmias that predispose to the occurrence of hydrops fetalis, cardiac dysfunction or eventual fetal demise require active treatments. Intrauterine therapy of fetal tachyarrhythmias has been carried out by the transplacental route. If maternal transplacental treatment fails, intraumbilical, intraperitoneal, or direct fetal intramuscular injection of antiarrhythmic agents can be attempted. Conclusions: The outcomes of intrauterine therapy of fetal tachyarrhythmias depend on the types or etiology of fetal arrhythmias and fetal conditions. Most are curable to a transplacental treatment by the first-line antiarrhythmic agents. Fetal cardiac pacings are effective methods to restore sinus rhythm in drug-resistant or hemodynamically compromised cases. Immediate postnatal pacemaker implantation is warranted in refractory cases.

Multiple direct fetal amiodarone administration for supraventricular tachycardia with hydrops fetalis: a case report

“… 4 , 9 The IP route is technically easier and provides a depot for sustained drug release but has a longer response. 10 The IV route provides direct access to the fetal circulation and allows quicker response but has the risk of cord injury and a shorter drug effect. 4 , 10 Combined direct intraumbilical and IP application results in immediate cardioversion and a longer drug effect.…”

“… 10 The IV route provides direct access to the fetal circulation and allows quicker response but has the risk of cord injury and a shorter drug effect. 4 , 10 Combined direct intraumbilical and IP application results in immediate cardioversion and a longer drug effect. Cord injury during IV drug administration can lead to hematoma, blood flow occlusion, and fetal death.…”

Fetal foramen ovale flap tracings, as determined by M-mode echocardiography between weeks 24 and 39 of gestation

“…Also, the ratio between the FO diameter and that of the right atrium was calculated [4], but still, fetal FO studies lack in quantitative assessment of its function. M-mode echocardiography, because of its very high frame rate, seems to be a reasonable tool to analyze features of FO function during the cardiac cycle of the fetal heart, as it turned out so far to be useful for fetal heart function monitoring [5,6]. This study aimed to analyze M-mode echocardiography at an atrial level in normal healthy fetuses and to establish normal ranges of quantitative parameters assessing FO flap movements relative to the atrial wall diameter.…”

Fetal Atrial Flutter Associated with Atrial Septal Aneurysm

“…The atrial rate for AF is usually 300–500 beats/min and is usually sustained with variable AV block, whereas the atrial rate for other atrial tachycardias is either nonsustained or sustained at an atrial rate of 180–240 beats/min. The ventricles cannot respond in a 1:1 fashion to the extremely fast atrial rates and so there is 2:1 or variable atrioventricular block [ 29 , 30 ]. Most cases of fetal AF are not associated with cardiac anomalies.…”