Fetal Arrhythmia Diagnosis and Pharmacologic Management

Abstract

One of the most successful achievements of fetal intervention is the pharmacologic management of fetal arrhythmias. This management usually takes place during the second or third trimester. While most arrhythmias in the fetus are benign, both tachy-and bradyarrhythmias can lead to fetal hydrops or cardiac dysfunction and require treatment under certain conditions. This review will highlight precise diagnosis by fetal echocardiography and magnetocardiography, the 2 primary means of diagnosing fetuses with arrhythmia. Additionally, transient or hidden arrhythmias such as bundle branch block, QT prolongation, and torsades de pointes, which can lead to cardiomyopathy and sudden unexplained death in the fetus, may also need pharmacologic treatment. The review will address the types of drug therapies; current knowledge of drug usage, efficacy, and precautions; and the transition to neonatal treatments when indicated. Finally, we will highlight new assessments, including the role of the nurse in the care of fetal arrhythmias. The prognosis for the human fetus with arrhythmias continues to improve as we expand our ability to provide intensive care unit-like monitoring, to better understand drug treatments, to optimize subsequent pregnancy monitoring, to effectively predict timing for delivery, and to follow up these conditions into the neonatal period and into childhood. Coordinated initiatives that facilitate clinical fetal research are needed to address gaps in knowledge and to facilitate fetal drug and device development.

Pharmacological Management of Cardiac Arrhythmias in the Fetal and Neonatal Periods: A Scientific Statement From the American Heart Association

“…Intraperitoneal, intra-amniotic, and intramuscular drug administration theoretically provides a sustained release of medication; however, this may be limited by unpredictable drug delivery. 20 Intracordal injection is effective but requires multiple injections and has a significant risk of procedural complication. 20 Direct fetal therapy also involves risk of the drug entering the maternal circulation and should be performed only at experienced centers.…”

“…22 Treatment of first-and second-degree AVB may prevent the progression to third-degree heart block. 20,23 Figure 3 illustrates a possible algorithm for immune-mediated AVB when treatment is considered. Hydroxychloroquine is not a medication for reversal of antibody-mediated heart block; however, 1 study suggests that it may reduce the recurrence rate by >50% in future siblings when given in the first trimester because of its suppression of the inflammatory anti-SSA/Roinduced fibrosis of the atrioventricular node.…”

“…If long QT syndrome or torsades de pointes is suspected, propranolol, mexiletine, lidocaine, and magnesium sulfate can be used. 2,19,20 Conversely, episodes of an accelerated idioventricular rhythm generally do not require treatment unless sustained and associated with hemodynamic compromise. 2…”

“…20 Intracordal injection is effective but requires multiple injections and has a significant risk of procedural complication. 20 Direct fetal therapy also involves risk of the drug entering the maternal circulation and should be performed only at experienced centers. 2,3…”

Monochorionic Twin Pregnancy Complicated by Arrhythmia in One Twin: Longitudinal Hemodynamic Effects of Flecainide Cardioversion Assessed by Fetal Venous Doppler

“…Transplacental antiarrhythmic treatment has proven successful in singletons with over 60% conversion rate. 4 Flecainide is preferred over digoxin in cases complicated by hydrops due to more effective transplacental transfer, even though similar results are reported with a more aggressive and invasive therapeutic approach. 5,6 We report a case of MC diamniotic (MCDA) twins where one twin developed tachyarrhythmia with hydrops and transplacental antiarrhythmic treatment was successful.…”