Pregnancy outcome after gestational exposure to amiodarone in Canada

In Vivo Evaluation of the Pharmacokinetic Interaction between Levothyroxine and Amiodarone in Rat Plasma: Evaluation of Importance of Therapeutic Drug Monitoring during Co-Therapy

Amiodarone-induced thyrotoxicosis (AIT) is a common condition in patients who are receiving amiodarone for cardiac arrhythmia. This risk is elevated in iodine-deficient regions. Levothyroxine is the standard treatment for patients with hypothyroidism. This investigation is concerned with the evaluation of the possible pharmacokinetic interaction between amiodarone and levothyroxine upon co-therapy in rats and to investigate the cause of thyrotoxicosis. A selective, sensitive and precise RP-HPLC method was developed for the simultaneous determination of levothyroxine and amiodarone in rat plasma. A stationary phase of C18 Xterra RP column and a mobile phase consisting of acetonitrile: acidified water with 0.1% trifluoracetic acid (pH = 4.8) with gradient elution were used. The experiment was conducted at ambient temperature with flow rate of 1.5 mL/min for the chromatographic separation and quantitation of the investigated drugs. Protein precipitation with methanol was applied for the analysis of the two drugs in rat plasma. The method was linear over concentration range of 5-200 μg/mL for both levothyroxine and amiodarone. The European Medicines Agency guideline was applied for the validation of the developed bioanalytical method. The method was successfully applied to in vivo pharmacokinetic study in which levothyroxine and amiodarone were quantified in plasma of rats after receiving an oral dose of levothyroxine and amiodarone. After the calculation of the pharmacokinetic parameters, a statistical analysis was performed to elucidate the existence of significant difference between test and control groups in rats. The combination of levothyroxine and amiodarone significantly decreased levothyroxine bioavailability in rats, making the therapeutic drug monitoring mandatory in patients receiving levothyroxine and amiodarone. In addition, the increased clearance of levothyroxine upon the co-administration with amiodarone may explain the reported hypothyroidism.

Obstetric and fetal/neonatal outcomes in pregnant women with frequent premature ventricular complexes and structurally normal heart

BACKGROUND

High premature ventricular complex (PVC) burden may increase the risk of left ventricular dysfunction and all-cause mortality. We aimed to evaluate maternal and neonatal outcomes of pregnant women with structurally normal heart having PVC burden ≥1%.

METHODS

This retrospective cohort study used data from Chang Gung Research Database. Pregnancies from January 1, 2005, through June 30, 2020, with documented maternal PVC burden ≥1% by 24-h Holter monitor were identified. Pregnant women with a diagnosis of structural heart disease or arrhythmias other than PVC were excluded. We used propensity score matching (PSM) to balance the covariates between the PVC group and normal control group. The PVC group was classified into low-PVC (<10%) and high-PVC burden subgroups. The maternal and neonatal outcomes were assessed through 6 months after delivery or termination.

RESULTS

After PSM, there were 214, 61, and 46 pregnant women enrolled in the normal control group, low-PVC burden, and high-PVC burden subgroups, respectively. The high-PVC and low-PVC burden subgroups had composite adverse maternal and neonatal events similar to the control group without use of antiarrhythmic drugs (AADs), but a higher proportion of placental abruption was observed in the high-PVC burden subgroup. Maternal age, diabetes, and overweight were significant predictors of composite adverse maternal events, whereas only maternal age was a significant predictor of composite adverse neonatal events.

CONCLUSIONS

High PVC burden was not associated with poor composite adverse maternal and neonatal outcomes with no need of AADs therapy in pregnant women with structurally normal heart.

Diagnosis and management of arrhythmias in pregnancy

Arrhythmias are the most common cardiac complications occurring in pregnancy. Although the majority of palpitations in pregnancy may be explained by atrial or ventricular premature complexes, the full spectrum of arrhythmias can occur. In this article, we establish a systematic approach to the evaluation and management of arrhythmias in pregnancy. Haemodynamically unstable arrhythmias warrant urgent cardioversion. For mild cases of benign arrhythmia, treatment is usually not needed. Symptomatic but haemodynamically stable arrhythmic patients should first undergo a thorough evaluation to establish the type of arrhythmia and the presence or absence of structural heart disease. This will ultimately determine the necessity for treatment given the potential risks of anti-arrhythmic pharmacotherapy in pregnancy. We will discuss the main catalogue of anti-arrhythmic medications, which have some established evidence of safety in pregnancy. Based on our appraisal, we provide a treatment algorithm for the tachyarrhythmic pregnant patient.

Atrial fibrillation during pregnancy: a 9-month period with limited options

Pregnancy is a physiological condition with reversible hemodynamic, neurohormonal and coagulation changes to the maternal body during this 9‑month period. The occurrence of atrial fibrillation (AF) is altogether rare among pregnant women, but necessitates immediate treatment und further work-up. Despite numerous pharmacological and invasive therapeutic modalities for AF in non-pregnant patients, very few options are considered safe enough for the fetus and the mother during pregnancy. Commonly used medications such as beta blockers, calcium channel antagonists, antiarrhythmic drugs and anticoagulation therapy must be carefully individualized according to the week of gestation and possible underlying comorbidities of the mother, thus highlighting the importance of an interdisciplinary evaluation by a cardiologist and a gynecologist. The current review summarizes the existing knowledge and treatment options for AF in pregnancy and suggests a simplified algorithm for this clinical constellation.

Cardiac arrhythmias in pregnant women: need for mother and offspring protection

Cardiac arrhythmias are the most common cardiac complication reported in pregnant women with and without structural heart disease (SHD); they are more frequent among women with SHD, such as cardiomyopathy and congenital heart disease (CHD). While older studies had indicated supraventricular tachycardia as the most common tachyarrhythmia in pregnancy, more recent data indicate an increase in the frequency of arrhythmias, with atrial fibrillation (AF) emerging as the most frequent arrhythmia in pregnancy, attributed to an increase in maternal age, cardiovascular risk factors and CHD in pregnancy. Importantly, the presence of any tachyarrhythmia during pregnancy may be associated with adverse maternal and fetal outcomes, including death. Thus, both the mother and the offspring need to be protected from such consequences. The use of antiarrhythmic drugs (AADs) depends on clinical presentation and on the presence of underlying SHD, which requires caution as it promotes pro-arrhythmia. In hemodynamically compromised women, electrical cardioversion is successful and safe to both mother and fetus. Use of beta-blockers appears quite safe; however, caution is advised when using other AADs, while no AAD should be used, if at all possible, during the first trimester when organogenesis takes place. Regarding the anticoagulation regimen in patients with AF, warfarin should be substituted with heparin during the first trimester, while direct oral anticoagulants are not indicated given the lack of data in pregnancy. Finally, for refractory arrhythmias, ablation and/or device implantation can be performed with current techniques in pregnant women, when needed, using minimal exposure to radiation. All these issues and relevant current guidelines are herein reviewed.

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.

Transient neonatal hypothyroidism following a short course of maternal amiodarone therapy

Background Amiodarone is an iodine-rich medication used to treat maternal and fetal arrhythmias, with known effects on thyroid hormone homeostasis. Case presentation We describe a case of transient neonatal hypothyroidism following a short prenatal course of maternal amiodarone therapy resulting in neonatal TSH elevations exceeding those reported in the available literature.

Health-Relevant Phenotypes in the Offspring of Mice Given CAR Activators Prior to Pregnancy

Hepatic induction in response to drugs and environmental chemicals affects drug therapies and energy metabolism. We investigated whether the induction is transmitted to the offspring. We injected 3-day- and 6-week-old F0 female mice with TCPOBOP, an activator of the nuclear receptor constitutive androstane receptor (CAR, NR1I3), and mated them 1-6 weeks afterward. We detected in the offspring long-lasting alterations of CAR-mediated drug disposition, energy metabolism, and lipid profile. The transmission to the first filial generation (F1) was mediated by TCPOBOP transfer from the F0 adipose tissue via milk, as revealed by embryo transfer, crossfostering experiments, and liquid chromatography-mass spectrometry analyses. The important environmental pollutant PCB153 activated CAR in the F1 generation in a manner similar to TCPOBOP. Our findings indicate that chemicals accumulating and persisting in adipose tissue may exert liver-mediated, health-relevant effects on F1 offspring simply via physical transmission in milk. Such effects may occur even if treatment has been terminated far ahead of conception. This should be considered in assessing developmental toxicity and in the long-term follow-up of offspring of mothers exposed to both approved and investigational drugs, and to chemicals with known or suspected accumulation in adipose tissue.

Early Gestational Hypoxia and Adverse Developmental Outcomes

Hypoxia is a normal and essential part of embryonic development. However, this state may leave the embryo vulnerable to damage when oxygen supply is disturbed. Embryofetal response to hypoxia is dependent on duration and depth of hypoxia, as well as developmental stage. Early postimplantation rat embryos were resilient to hypoxia, with many surviving up to 1.5 hr of uterine clamping, while most mid-gestation embryos were dead after 1 hour of clamping. Survivors were small and many had a range of defects, principally terminal transverse limb reduction defects. Similar patterns of malformations occurred when embryonic hypoxia was induced by maternal hypoxia, interruption of uteroplacental flow, or perfusion and embryonic bradycardia. There is good evidence that high altitude pregnancies are associated with smaller babies and increased risk of some malformations, but these results are complicated by increased risk of pre-eclampsia. Early onset pre-eclampsia itself is associated with small for dates and increased risk of atrio-ventricular septal defects. Limb defects have clearly been associated with chorionic villus sampling, cocaine, and misoprostol use. Similar defects are also observed with increased frequency among fetuses who are homozygous for thalassemia. Drugs that block the potassium current, whether as the prime site of action or as a side effect, are highly teratogenic in experimental animals. They induce embryonic bradycardia, hypoxia, hemorrhage, and blisters, leading to transverse limb defects as well as craniofacial and cardiovascular defects. While evidence linking these drugs to birth defects in humans is not compelling, the reason may methodological rather than biological. Birth Defects Research 109:1358-1376, 2017.© 2017 Wiley Periodicals, Inc.

Concurrent maternal and fetal tachyarrhythmia in pregnancy

The occurrence of a maternal and fetal tachyarrhythmia together in pregnancy is exceedingly rare. We report a case of a persistent fetal atrial ectopic tachycardia occurring in conjunction with a maternal atrial tachycardia with left ventricular systolic dysfunction. Amiodarone was effective in treating both maternal and fetal arrhythmias.

Evaluation and Management of Maternal Cardiac Arrhythmias

Pregnant women often complain of palpitations. The differential diagnosis for new-onset palpitations in pregnancy ranges from benign conditions to life-threatening arrhythmias. Maternal arrhythmias can occur in isolation or in the setting of underlying structural heart disease. Optimal management of maternal cardiac arrhythmias includes identification of the specific arrhythmia, diagnosis of comorbid conditions, and appropriate intervention. In general, management of maternal cardiac arrhythmias is similar to that of the general population. Special consideration must be given as to the effects of medications and procedures on both the mother and fetus to optimize outcomes. The importance of multidisciplinary care with cardiology, obstetrics, and anesthesia is emphasized.

Antiarrhythmic drugs in pregnancy

The risk of arrhythmia development or recurrence is increased during pregnancy. For those arrhythmias that are unresponsive to conservative therapy, such as vagal maneuvers or life style interventions, or that present a higher risk to the mother or fetus, medical therapy may be necessary. In each case, the patient and provider must carefully consider the risks and benefits of a particular therapy. This requires an understanding of the data regarding the safety and efficacy of any particular drug, which in some cases may be extensive and in others quite limited. Fortunately, options exist for the treatment of arrhythmias during pregnancy.

Protocol of the PSYCHOTSH study: association between neonatal thyroid stimulating hormone concentration and intellectual, psychomotor and psychosocial development at 4-5 year of age: a retrospective cohort study

Background

Several European countries, including Belgium, still suffer from mild iodine deficiency. Thyroid stimulating hormone (TSH) concentration in whole blood measured at birth has been proposed as an indicator of maternal iodine status during the last trimester of pregnancy. It has been shown that mild iodine deficiency during pregnancy may affect the neurodevelopment of the offspring. In several studies, elevated TSH levels at birth were associated with suboptimal cognitive and psychomotor outcomes among young children. This paper describes the protocol of the PSYCHOTSH study aiming to assess the association between neonatal TSH levels and intellectual, psychomotor and psychosocial development of 4–5 year old children. The results could lead to a reassessment of the recommended cut-off levels of 5 > mU/L used for monitoring iodine status of the population.

Methods

In total, 380 Belgian 4–5 year old preschool children from Brussels and Wallonia with a neonatal blood spot TSH concentration between 0 and 15 mU/L are included in the study. For each sex and TSH-interval (0–1, 1–2, 2–3, 3–4, 4–5, 5–6, 6–7, 7–8, 8–9 and 9–15 mU/L), 19 newborns were randomly selected from all newborns screened by the neonatal screening centre in Brussels in 2008–2009. Infants with congenital hypothyroidism, low birth weight and prematurity were excluded from the study. Neonatal TSH concentration was measured by the Autodelphia method in dried blood spots, collected by heel stick on filter paper 3 to 5 days after birth. Cognitive abilities and psychomotor development are assessed using the Wechsler Preschool and Primary Scale of Intelligence - third edition - and the Charlop-Atwell Scale of Motor coordination. Psychosocial development is measured using the Child Behaviour Check List for age 1½ to 5 years old. In addition, several socioeconomic, parental and child confounding factors are assessed.

Conclusions

This study aims to clarify the effect of mild iodine deficiency during pregnancy on the neurodevelopment of the offspring. Therefore, the results may have important implications for future public health recommendations, policies and practices in food supplementation. In addition, the results may have implications for the use of neonatal TSH screening results for monitoring the population iodine status and may lead to the definition of new TSH cut-offs for determination of the severity of iodine status and for practical use in data reporting by neonatal screening centres.

Pregnancy in adult congenital heart disease

Cardiac disease in pregnancy is a challenging health care problem. The number of cases and their complexity is increasing, such that heart disease is now the leading cause of maternal mortality in developed countries. Numerically, women with congenital heart disease (CHD) make up the majority of cases and although maternal mortality is infrequent, a good outcome is only achieved though meticulous care, which starts pre-pregnancy and continues for months after the pregnancy has ended. All women with CHD should be assessed and counseled before pregnancy and carefully monitored during pregnancy, the delivery and in the puerperium. In most cases, pregnancy is well tolerated but in some conditions, such as pulmonary hypertension or severe dilatation of the aorta, pregnancy is extremely high risk and should be advised against.

Mild iodine deficiency in pregnancy in Europe and its consequences for cognitive and psychomotor development of children: a review

Despite the introduction of salt iodization programmes as national measures to control iodine deficiency, several European countries are still suffering from mild iodine deficiency (MID). In iodine sufficient or mildly iodine deficient areas, iodine deficiency during pregnancy frequently appears in case the maternal thyroid gland cannot meet the demand for increasing production of thyroid hormones (TH) and its effect may be damaging for the neurodevelopment of the foetus. MID during pregnancy may lead to hypothyroxinaemia in the mother and/or elevated thyroid-stimulating hormone (TSH) levels in the foetus, and these conditions have been found to be related to mild and subclinical cognitive and psychomotor deficits in neonates, infants and children. The consequences depend upon the timing and severity of the hypothyroxinaemia. However, it needs to be noted that it is difficult to establish a direct link between maternal iodine deficiency and maternal hypothyroxinaemia, as well as between maternal iodine deficiency and elevated neonatal TSH levels at birth. Finally, some studies suggest that iodine supplementation from the first trimester until the end of pregnancy may decrease the risk of cognitive and psychomotor developmental delay in the offspring.

Cardiovascular disasters in pregnancy

Cardiovascular emergencies in pregnancy are rare but often catastrophic. This article reviews the diagnosis and management of venous thromboembolism, aortic dissection, acquired heart disease and cardiomyopathy, acute myocardial infarction, and cardiac dysrhythmias in the setting of pregnancy. It also reviews updated resuscitation guidelines for cardiac arrest and perimortem cesarean section.

Cardiac arrhythmias during pregnancy

OPINION STATEMENT

This article reviews the appropriate evaluation and management of cardiac arrhythmias in the pregnant patient. Any treatment strategy in this patient population has the inherent potential to adversely affect the health of the unborn child. As such, there is no room for empiric therapy in these patients. Adequate arrhythmia documentation is paramount, preferably by noninvasive means. The decision to treat should be based on symptom severity and the risk to both mother and fetus posed by potentially recurring arrhythmia episodes throughout the pregnancy. Minimal symptoms in the setting of a structurally normal heart call for a conservative approach. Less is better. If pharmacologic therapy is justified, drugs with historically demonstrated safety profiles in pregnancy should be tried first. The safety profiles of virtually all drugs used to treat cardiac arrhythmias during human pregnancy are based solely on an accumulation of past clinical experience. Newer antiarrhythmics therefore carry a largely unknown risk. Most inherent rhythm disorders manifest long before a woman reaches childbearing age. Women with previously diagnosed arrhythmias frequently experience a recurrence or worsening of their arrhythmia during the pregnancy. Counseling of these individuals and perhaps preemptive treatment by means such as arrhythmia ablation prior to a planned pregnancy would seem optimal.

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.

[Thyroid and pregnancy]

Pregnancy is associated with an increased requirement of hormone secretion by the thyroid, within the first weeks after conception. To this greater demand to occurs, pregnancy induces a series of physiological changes that affect thyroid function and, consequently, the tests of glandular function. For normal pregnant women living in areas with a sufficient supply of iodine, this challenge regarding the adjustment of thyroid hormone releases to this new state of equilibrium and its maintenance until the end of pregnancy it meets no difficulties. However, among women with impaired thyroid function due to some thyroid disease or among women residing in areas with an insufficient iodine supply, this does not occur. The management of thyroid dysfunction during gestation requires special considerations, since both hypothyroidism and hyperthyroidism can lead to maternal and fetal complications. In addition, thyroid nodules are detected at reasonable frequency among pregnant women, a fact that requires a differential diagnosis between benign and malignant growths during the pregnancy itself.

Right ventricular outflow tract tachycardia in the parturient

Parturition is marked by physiological changes that may elicit electrocardiographic anomalies. Sustained right ventricular tachycardia is an uncommon arrhythmia that necessitates cardioversion using physical, pharmaceutical or electrical means. Patients with right ventricular tachycardia must be evaluated for right ventricular dysplasia. Long-term management of right ventricular tachycardia includes beta-adrenergic blockade and/or radio ablation of right ventricle outflow region usually below the pulmonary annuls. This report discusses the case of a 28-year-old previously healthy primigravid who experienced right ventricular outflow tract tachycardia during labor.

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.

Arrhythmias in the pregnant patient: Current concepts in evaluation and management

Maternal arrhythmias during pregnancy may jeopardize the health of both mother and fetus. The correct identification of the arrhythmia is critical in the pregnant patient. Treatment should be reserved for arrhythmias that are hemodynamically unstable or cause debilitating symptoms. When medications are deemed necessary, the physician should use as few drugs as possible at the lowest effective doses and choose drugs with a history of safe use in pregnancy. Resuscitation of a pregnant patient in cardiac arrest should be modified with regard to the normal physiologic changes of pregnancy. With careful management, most of these challenging patients will have excellent outcomes.

Pregnancy: Maternal and Fetal Heart Disease

Cardiac disorders complicate less than 1% of all pregnancies. Physiologic changes in pregnancy may mimic heart disease. In order to differentiate these adaptations from pathologic conditions, an in-depth knowledge of cardiovascular physiology is mandatory. A comprehensive history, physical examination, electrocardiogram, chest radiograph, and echocardiogram are sufficient in most cases to confirm the diagnosis. Care of women with cardiac disease begins with preconception counseling. Severe lesions should be taken care of prior to contemplating pregnancy. Management principles for pregnant women are similar to those for the non-pregnant state. A team approach comprised of a maternal fetal medicine specialist, cardiologist, neonatologist, and anesthesiologist is essential to assure optimal outcome for both the mother and the fetus. Although fetal heart disease complicates only a small percentage of pregnancies, congenital heart disease causes more neonatal morbidity and mortality than any other congenital malformation. Unfortunately, screening approaches for fetal heart disease continue to miss a large percentage of cases. This weakness in fetal screening has important clinical implications, because the prenatal detection and diagnosis of congenital heart disease may improve the outcome for many of these fetal patients. In fact, simply the detection of major heart disease prenatally can improve neonatal outcome by avoiding discharge to home of neonates with ductal-dependent congenital heart disease. Fortunately, recent advances in screening techniques, an increased ability to change the prenatal natural history of many forms of fetal heart disease, and an increasing recognition of the importance of a multidisciplinary, team approach to the management of pregnancies complicated with fetal heart disease, together promise to improve the outcome of the fetus with congenital heart disease.

FETAL BRADYCARDIA. A PRACTICAL APPROACH

Fetal bradycardia may herald fetal demise. This article highlights arrhythmic fetal bradycardia rather than bradycardia caused by perinatal distress. We briefly examine the embryonic conduction system's development and physiology and we review the classification, aetiology, evaluation, and approach to fetal bradycardia. Our aim is to provide the clinician with practical information about fetal bradycardia that enlightens causative conditions and aids management.

Successful treatment of atrial flutter with amiodarone in a premature neonate. Case report and literature review

This case report describes a 30-week gestation neonate who presented at birth with hydrops fetalis due to atrial flutter. Digoxin and electric cardioversion were unsuccessful in maintaining a stable sinus rhythm. The infant continued with intractable atrial flutter and severe hemodynamic deterioration until intravenous loading of amiodarone achieved conversion to stable sinus rhythm. Amiodarone was continued for 45 days; there was no recurrence of atrial flutter. Of note, the infant developed severe chronic lung disease after mechanical ventilation for 28 days. A lung biopsy ruled out amiodarone-induced pulmonary toxicity. A table is provided reviewing the different forms of neonatal supraventricular tachycardias. Apart from the successful management of the tachycardia, the role of amiodarone as an effective antiarrhythmic agent and its potential side effects, such as pulmonary toxicity and transient hypothyroidism, are discussed.

Acute therapy of maternal and fetal arrhythmias during pregnancy

Atrial premature beats are frequently diagnosed during pregnancy. Supraventricular tachycardia (atrial tachycardia, atrioventricular nodal reentrant tachycardia, circus movement tachycardia) is diagnosed less frequently. For acute therapy, electrical cardioversion with 50 to 100 J is indicated in all unstable patients. In stable supraventricular tachycardia, the initial therapy includes vagal maneuvers to terminate tachycardias. For short-term management, when vagal maneuvers fail, intravenous adenosine is the first choice drug and may safely terminate the arrhythmia. Ventricular premature beats are also frequently present during pregnancy and are benign in most patients; however, malignant ventricular tachyarrhythmias (sustained ventricular tachycardia, ventricular flutter, or ventricular fibrillation) may occur. Electrical cardioversion is necessary in all patients who are hemodynamically unstable with life-threatening ventricular tachyarrhythmias. In hemodynamically stable patients, initial therapy with ajmaline, procainamide, or lidocaine is indicated. In patients with syncopal ventricular tachycardia, ventricular fibrillation, ventricular flutter, or aborted sudden death, an implantable cardioverter-defibrillator is indicated. In patients with symptomatic bradycardia, a pacemaker can be implanted using echocardiography at any stage of pregnancy. The treatment of the pregnant patient with cardiac arrhythmias requires important modifications of the standard practice of arrhythmia management. The goal of therapy is to protect the patient and fetus through delivery, after which chronic or definitive therapy can be administered.

Thyroid medications during pregnancy

Euthyroid women experience dramatic changes in their thyroid physiology in order to accommodate the presence of placental and fetal tissues. These adaptations to the pregnant state make it crucial to develop reliable trimester-specific intervals for thyroid parameters. Use of non-pregnant reference intervals could lead to erroneous assessment of thyroid status in this rapidly changing hormonal environment. Only with a full appreciation of physiologic changes in thyroid parameters during a euthyroid pregnancy, can thyroid dysfunction be appropriately diagnosed and managed. Iodine sufficiency during pregnancy can be achieved with supplementation using a multivitamin. Both hypothyroidism and hyperthyroidism should be diagnosed using the appropriate reference intervals for pregnancy. Hypothyroid women are best treated with a specific brand of levothyroxine. Hypothyroidism should ideally be treated prior to conception. If newly recognized during pregnancy, it should be fully treated as early as possible. Frequent monitoring of thyroid status is essential as many women demonstrate an increased requirement for thyroid hormone during the first trimester. Although mild hyperthyroidism may be well tolerated during pregnancy, overt hyperthyroidism requires treatment. Thionamides are the mainstay of therapy. Following their initiation, close monitoring is required to avoid maternal and fetal hypothyroidism. There are occasional circumstances when other medical therapy or surgical therapy may be employed for hyperthyroidism. Thyroidectomy is generally safe in the second trimester in an appropriately prepared woman. There is limited data about the role and safety of oral contrast agents, iodine, amiodarone, and perchlorate. Radioiodine therapy is contradicted during pregnancy.

Recurrence rates of arrhythmias during pregnancy in women with previous tachyarrhythmia and impact on fetal and neonatal outcomes

In women with heart disease, sustained arrhythmias can result in an increased risk to the mother and fetus. The purpose of this study was to determine the recurrence rates of arrhythmias during pregnancy in women with cardiac rhythm disorders and examine the impact on fetal and neonatal outcomes. Women with tachyarrhythmias before pregnancy who underwent obstetric care at the Toronto General and Mount Sinai Hospitals from 1990 to 2002 were included. The recurrence rates of arrhythmias were calculated. A multivariate logistic model was used to identify predictors of fetal complications. Seventy-three women had 87 pregnancies; 36 pregnancies were in women with a history of paroxysmal supraventricular tachycardia, 23 with paroxysmal atrial fibrillation or atrial flutter (AF/Afl), 6 with persistent AF/Afl, and 22 with ventricular tachycardia. In the women in sinus rhythm at baseline, 44% (36 of 81 pregnancies) developed recurrences of tachyarrhythmias during pregnancy or in the early postpartum period. The specific recurrence rates during pregnancy in women with a history of supraventricular tachycardia, paroxysmal AF/Afl, and ventricular tachycardia were 50%, 52%, and 27%, respectively. The 6 women in AF/Afl at baseline remained in this rhythm throughout their pregnancy. Adverse fetal events occurred in 17 of the 87 pregnancies (20%). Adverse fetal events occurred more commonly in women who developed antepartum arrhythmias (RR 3.4, 95% confidence interval 1.0 to 11.0, p = 0.045) compared with those who did not. In conclusion, in women with preexisting cardiac rhythm disorders, exacerbation of arrhythmia during pregnancy is common. Recurrence of arrhythmia during the antepartum period increases the risk of adverse fetal complications, independent of other maternal and fetal risk factors.

Cardiovascular drugs for the newborn

This article reviews the various cardiovascular drugs for newborns, including antiarrhythmics, antihypertensives, inotropes, and pulmonary vasodilators. Antiarrhythmic drugs are classified according to their mechanisms of action, such as effects on ion channels, duration of repolarization, and receptor interaction, which help with understanding the effects of individual antiarrhythmic drugs and selection of drugs for specific arrhythmias. Drug treatment for hypertension should start with a single drug from one of the following classes: ACE inhibitors, angiotensin-receptor antagonists, beta-receptor antagonists, calcium channel blockers, or diuretics. The inotropic drug should be selected according to its specific pharmacologic properties and the specific cardiovascular abnormality to be corrected. An effective pulmonary vasodilator must dilate the pulmonary vasculature more than the systemic vasculature.

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.

Cardiac disease in pregnancy

This article reviews the complications, management and prognosis of cardiac disease in pregnancy.

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.

Role of amiodarone in the treatment of fetal supraventricular tachyarrhythmias and hydrops fetalis

We report three consecutive hydropic fetuses with fetal tachyarrhythmias treated with amiodarone-two in combination with digoxin and one with digoxin, procainamide, and propranolol. Sinus rhythm was achieved in one case and ventricular rate control was achieved in two cases. All fetuses treated with amiodarone gradually improved. Observed side effects of amiodarone were a maternal rash in one mother and transient neonatal hypothyroidism in one infant. We conclude that amiodarone might be effective and safe for fetal tachyarrhythmias and impending hydrops. The small number of patients suggests that a multicenter cooperative approach is required in order to determine if this is correct.

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.

Drug treatment of fetal tachycardias

The pharmacological treatment of fetal tachycardia (FT) has been described in various publications. We present a study reviewing the necessity for treatment of FT, the regimens of drugs used in the last two decades and their mode of administration. The absence of reliable predictors of fetal hydrops (FH) has led most centers to initiate treatment as soon as the diagnosis of FT has been established, although a small minority advocate nonintervention. As the primary form of pharmacological intervention, oral maternal transplacental therapy is generally preferred. Digoxin is the most common drug used to treat FT; however, effectiveness remains a point of discussion. After digoxin, sotalol seems to be the most promising agent, specifically in atrial flutter and nonhydropic supraventricular tachycardia (SVT). Flecainide is a very effective drug in the treatment of fetal SVT, although concerns about possible pro-arrhythmic effects have limited its use. Amiodarone has been described favorably, but is frequently excluded due to its poor tolerability. Verapamil is contraindicated as it may increase mortality. Conclusions on other less frequently used drugs cannot be drawn. In severely hydropic fetuses and/or therapy-resistant FT, direct fetal therapy is sometimes initiated. To minimize the number of invasive procedures, fetal intramuscular or intraperitoneal injections that provide a more sustained release are preferred. Based on these data we propose a drug protocol of sotalol 160 mg twice daily orally, increased to a maximum of 480 mg daily. Whenever sinus rhythm is not achieved, the addition of digoxin 0.25 mg three times daily is recommended, increased to a maximum of 0.5 mg three times daily. Only in SVT complicated by FH, either maternal digoxin 1 to 2mg IV in 24 hours, and subsequently 0.5 to 1 mg/day IV, or flecainide 200 to 400 mg/day orally is proposed. Initiating direct fetal therapy may follow failure of transplacental therapy.