Neurodevelopment after in utero amiodarone exposure

2023 HRS expert consensus statement on the management of arrhythmias during pregnancy

This international multidisciplinary expert consensus statement is intended to provide comprehensive guidance that can be referenced at the point of care to cardiac electrophysiologists, cardiologists, and other health care professionals, on the management of cardiac arrhythmias in pregnant patients and in fetuses. This document covers general concepts related to arrhythmias, including both brady- and tachyarrhythmias, in both the patient and the fetus during pregnancy. Recommendations are provided for optimal approaches to diagnosis and evaluation of arrhythmias; selection of invasive and noninvasive options for treatment of arrhythmias; and disease- and patient-specific considerations when risk stratifying, diagnosing, and treating arrhythmias in pregnant patients and fetuses. Gaps in knowledge and new directions for future research are also identified.

Management of tachyarrhythmias in pregnancy - A review

The most common arrhythmias detected during pregnancy include sinus tachycardia, sinus bradycardia, and sinus arrhythmia, identified in 0.1% of pregnancies. Isolated premature atrial or ventricular arrhythmias are observed in 0.03% of pregnancies. Arrhythmias may become more frequent during pregnancy or may manifest for the first time.

Foetal supraventricular tachycardia with hydrops fetalis: a role for direct intraperitoneal amiodarone

INTRODUCTION

Persistent foetal tachyarrythmias complicated by hydrops fetalis carry a poor prognosis, with foetal death reported in excess of a quarter despite treatment. We present our experience with direct intraperitoneal amiodarone administration in eight hydropic foetuses with resistant supraventricular tachycardia.

METHODS

Amiodarone was injected slowly into foetal peritoneal cavity under ultrasound guidance. All mothers were loaded with oral amiodarone before the procedure and maintained on it. The procedure was repeated guided by foetal rhythm.

RESULT

All eight cases had severe hydrops with a median foetal heart rate of 255 bpm (range 240-300 bpm), and the median gestational age was 27+1 weeks (range 21-33+3 weeks) at presentation. In six cases, the average time for supraventricular tachycardia to revert to sinus rhythm from the first procedure was 11.5 days. In one case, intravascular injection of amiodarone into the umbilical vein was performed before intraperitoneal injection, which resulted in conversion to sinus rhythm sustained until delivery. In the last case, supraventricular tachycardia and severe hydrops persisted and the baby was delivered 5 days later at 34 weeks' gestation. Hydrops resolved in five foetuses with a mean resolution time of 28.4 days. The mean gestational age at delivery was 34+5 days and seven of eight cases survived beyond the neonatal period with good postnatal outcomes.

CONCLUSION

Intraperitoneal administration of amiodarone is a relatively simple and effective strategy in refractory supraventricular tachycardia complicated by severe hydrops. The intraperitoneal route assures delivery of the drug to the severely hydropic foetus and enables a bolus dose to be delivered for sustained absorption.

Maternal cardiac arrhythmias during pregnancy and lactation

Arrhythmias occurring during pregnancy can cause significant symptoms and even death in mother and fetus. The management of these arrhythmias is complicated by the need to avoid harm to the fetus and neonate. It is useful to classify patients with arrhythmias into those with and without structural heart disease. Those with a primary electrical problem, but an otherwise normal heart, often tolerate rapid heart rates without compromise whereas patients with problems such as rheumatic heart disease, congenital heart disease or cardiomyopathy may quickly decompensate during an arrhythmia.

Hipotireoidismo neonatal transitório causado pelo uso de amiodarona durante a gestação: relato de dois casos e revisão da literatura

INTRODUÇÃO: A amiodarona (AMD) é uma droga antiarrítmica que contém 37% de iodo. A AMD pode alcançar o feto por via transplacentária e causar hipotireoidismo congênito (HC) ou transitório (HCT). Relatamos dois casos de HCT em virtude de exposição gestacional à AMD, detectados pelo programa de triagem neonatal para HC no Estado do Paraná, Brasil. CASO CLÍNICO 1 (C1): TSH neonatal 78,2 mU/L (normal < 15 mU/L). A AMD foi utilizada durante toda a gestação em virtude de arritmia materna. As dosagens séricas iniciais confirmaram o HC; e na primeira consulta [aos 14 dias de vida (dv)], foi iniciada levotiroxina (L-T4), 50 µg/dia. CASO CLÍNICO 2 (C2): TSH neonatal 134 mU/L. A AMD foi utilizada no último trimestre da gestação em virtude de arritmia materna. As dosagens séricas iniciais confirmaram o HC; aos 13 dv, foi iniciada L-T4 50 µg/dia. ACOMPANHAMENTO: TSH e T4 estavam normais aos 51 dv (C1) e aos 36 dv (C2) sendo então gradativamente reduzida a dose da medicação e suspensa aos 16 meses (C1) e aos dez meses (C2). As pacientes foram acompanhadas até 22 meses (C1) e 16 meses (C2) com testes de função tireoidiana normais. O crescimento e o desenvolvimento neuropsicomotor (DNPM), avaliados pelo teste CAT/CLAMS, eram normais. CONCLUSÃO: As avaliações da função tireoidiana e do DNPM são necessários quando a AMD é utilizada na gestação. O tratamento do HCT deve ser instituído tão logo o diagnóstico seja realizado.

Cardiovascular pharmacotherapeutic considerations during pregnancy and lactation

Cardiovascular drugs are often used in pregnancy for the treatment of maternal and fetal conditions. Mothers could also require continued postpartum drug therapy. Most cardiovascular drugs taken by pregnant women can cross the placenta and therefore expose the developing embryo and fetus to their pharmacologic and teratogenic effects. These effects are influenced by the intrinsic pharmacokinetic properties of a given drug as well as by the complex physiological changes occurring during pregnancy. Many drugs are also transferred into human milk and therefore can potentially have adverse effects on the nursing infant. This 2-part article summarizes some of the available literature concerning the risks and benefits of using various cardiovascular drugs and drug classes during pregnancy and lactation. Included in the discussion are cardiac glycosides, antiarrhythmic drugs, drugs used to treat both acute and chronic hypertension, cholesterol-lowering agents, anticoagulants, thrombolytics, and antiplatelet drugs.

Amiodarone-induced neonatal hypothyroidism: a unique form of transient early-onset hypothyroidism

Amiodarone is an iodine-rich drug used to treat cardiac dysrhythmias. The structure of amiodarone resembles that of thyroxine, and treatment with amiodarone may alter thyroid function. The effects of antenatal amiodarone use on fetal/neonatal thyroid function have only been addressed in a limited number of patient reports. We describe two cases of transient neonatal hypothyroidism due to in utero amiodarone exposure, followed by a brief review of the available literature.

Fetal supraventricular tachycardia: a role for amiodarone as second-line therapy?

OBJECTIVE

The aim of this study was to evaluate the role of amiodarone for the prenatal treatment of hydropic fetuses with supraventricular tachycardia.

METHODS

A group of 26 hydropic fetuses with supraventricular tachycardia was studied retrospectively.

RESULTS

Twenty-five fetuses received transplacental treatment. The overall prenatal conversion rate was 60%. Nine fetuses were converted to sinus rhythm using either flecainide (n = 7) or amiodarone (n = 2) as first line therapy, whilst digoxin alone or in association with sotalol failed to restore sinus rhythm in all cases. After first-line therapy, supraventricular tachycardia persisted in 10 fetuses. Nine fetuses received amiodarone alone or in association with digoxin as second-line therapy, five of whom were converted to sinus rhythm. Among the 11 live neonates treated by amiodarone in utero, 2 (17%) presented an elevated thyroid stimulating hormone at day 3-4. These two infants received thyroid hormone substitution therapy and had a normal outcome.

CONCLUSION

When first-line therapy fails to restore sinus rhythm in hydropic fetuses with supraventricular tachycardia, amiodarone therapy should be considered as it allows a substantial number of fetuses to be converted prenatally.

Drugs in pregnancy. Drugs to avoid

Drugs given in pregnancy can adversely affect the fetus in many ways. Anxiety about birth defects is a major parental concern during pregnancy. Doctors, midwives and their patients often seek information about the potential teratogenicity of drugs that are taken by, or prescribed for, the pregnant woman. Because no drug is entirely without side-effects, great caution should be taken when prescribing in pregnancy. The development of knowledge in understanding the use of drugs during pregnancy has been in stalemate in comparison to other areas of therapeutics, due mainly to difficulties in testing new products in pregnant women and lack of good quality research. In this chapter, we review current knowledge of the epidemiology of drug use among pregnant women, drug metabolism in pregnancy, adverse fetal and neonatal effects of drugs and specific effects of drugs that are relatively or absolutely contraindicated in pregnancy.

The effects of amiodarone on the thyroid

Amiodarone is a benzofuranic-derivative iodine-rich drug widely used for the treatment of tachyarrhythmias and, to a lesser extent, of ischemic heart disease. It often causes changes in thyroid function tests (typically an increase in serum T(4) and rT(3), and a decrease in serum T(3), concentrations), mainly related to the inhibition of 5'-deiodinase activity, resulting in a decrease in the generation of T(3) from T(4) and a decrease in the clearance of rT(3). In 14-18% of amiodarone-treated patients, there is overt thyroid dysfunction, either amiodarone-induced thyrotoxicosis (AIT) or amiodarone-induced hypothyroidism (AIH). Both AIT and AIH may develop either in apparently normal thyroid glands or in glands with preexisting, clinically silent abnormalities. Preexisting Hashimoto's thyroiditis is a definite risk factor for the occurrence of AIH. The pathogenesis of iodine-induced AIH is related to a failure to escape from the acute Wolff-Chaikoff effect due to defects in thyroid hormonogenesis, and, in patients with positive thyroid autoantibody tests, to concomitant Hashimoto's thyroiditis. AIT is primarily related to excess iodine-induced thyroid hormone synthesis in an abnormal thyroid gland (type I AIT) or to amiodarone-related destructive thyroiditis (type II AIT), but mixed forms frequently exist. Treatment of AIH consists of L-T(4) replacement while continuing amiodarone therapy; alternatively, if feasible, amiodarone can be discontinued, especially in the absence of thyroid abnormalities, and the natural course toward euthyroidism can be accelerated by a short course of potassium perchlorate treatment. In type I AIT the main medical treatment consists of the simultaneous administration of thionamides and potassium perchlorate, while in type II AIT, glucocorticoids are the most useful therapeutic option. Mixed forms are best treated with a combination of thionamides, potassium perchlorate, and glucocorticoids. Radioiodine therapy is usually not feasible due to the low thyroidal radioiodine uptake, while thyroidectomy can be performed in cases resistant to medical therapy, with a slightly increased surgical risk.

Effects of amiodarone administration during pregnancy on neonatal thyroid function and subsequent neurodevelopment

Amiodarone, a benzofuranic derivative, iodine-rich drug, has been used in pregnancy for either maternal or fetal tachyarrhythmias. Amiodarone, its main metabolite (desethylamiodarone) and iodine are transferred, albeit incompletely, through the placenta, resulting in a relevant fetal exposure to the drug and iodine overload. Since the fetus acquires the capacity to escape from the acute Wolff-Chaikoff effect only late in gestation, the iodine overload may cause fetal/neonatal hypothyroidism and goiter. Among the reported 64 pregnancies in which amiodarone was given to the mother, 11 cases (17%) of hypothyroidism in the progeny (10 detected at birth, 1 in utero) were reported, 9 non-goitrous (82%) and 2 (18%) associated with goiter. Hypothyroidism was transient in all cases, and only 5 infants were treated short-term with thyroid hormones. Only 2 newborns had transient hyperthyroxinemia, associated with low serum TSH concentrations in one. Neurodevelopment assessment of the hypothyroid infants, when carried out, showed in some instances mild abnormalities, most often reminiscent of the Non-verbal Learning Disability Syndrome; however, these features were also reported in some amiodarone-exposed euthyroid infants, suggesting that there might be a direct neurotoxic effect of amiodarone during fetal life. Breast-feeding was associated with a substantial ingestion of amiodarone by the infant, but in the few cases followed it did not cause changes in the newborn's thyroid function. In conclusion, amiodarone therapy during pregnancy may cause fetal/neonatal hypothyroidism and, less frequently, goiter. Thus, the use of amiodarone in pregnancy should be limited to maternal/fetal tachyarrhythmias which are resistant to other drugs or life-threatening. If amiodarone is used during gestation, a careful fetal/neonatal evaluation of thyroid function and morphology is warranted. It seems prudent to advise that fetal/neonatal hypothyroidism be treated, as soon as the diagnosis is made, even in utero, to avoid neurodevelopment abnormalities, although the latter may occur independently of hypothyroidism. If breast-feeding is allowed, careful evaluation of the infant's thyroid function and morphology is required because of the continuing exposure of the infant to the drug.

Fetal cardiology

The prevalence of congenital heart disease increases with increasing NT, and many defects can be detected by echocardiography performed by a specialist at 13 to 17 weeks. There is increasing evidence that a prenatal diagnosis improves fetal outcome. Physiology and pathophysiology of the human fetal pulmonary circulation play an important role in the fetal circulation, and recent studies about the reactivity of these vessels in the third trimester have contributed to increase our understanding. The main issue in fetal arrhythmias (brady- and tachycardia) is the correct indication, efficacy, and safety of treatment.