The efficacy of flecainide versus digoxin in the management of fetal supraventricular tachycardia

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.

Atrial Flutter in Pediatric Patients

Atrial flutter (AFL) in pediatric patients is a rare condition as the physical dimensions of the immature heart are inadequate to support the arrhythmia. This low incidence makes it difficult for patients in this particular setting to be studied. AFL accounts for 30% of fetal tachyarrhythmias, 11% to 18% of neonatal tachyarrhythmias, and 8% of supraventricular tachyarrhythmias in children older than 1 year of age. Transesophageal overdrive pacing can be used, instead, with lower success rate (60%-70%). The recommended drugs are digoxin which can decrease the ventricular rate until the spontaneous interruption of the AFL. Digoxin can be combined with flecainide or amiodarone in case of failure.

Transplacental treatment of foetal supraventricular tachycardia with triple antiarrhythmic combination to avoid intra-foetal intervention

Although a high percentage of foetuses with supraventricular tachycardia respond to single or dual antiarrhythmic therapy, on occasion when there is no response to these combination regimens, direct intra-foetal therapy remains the only choice, albeit such an approach carries a potential risk to the foetus.Data with regard to the safety and efficacy of triple antiarrhythmic combination have not been reported before. Here, we present a foetus with intractable tachycardia in whom arrhythmia termination was successfully achieved with triple oral antiarrhythmic therapy.

Efficacy and Safety of Various First-Line Therapeutic Strategies for Fetal Tachycardias: A Network Meta-Analysis and Systematic Review

Background: Fetal arrhythmias are common cardiac abnormalities associated with high mortality due to ventricular dysfunction and heart failure, particularly when accompanied by hydrops. Although several types of common fetal tachycardias have been relatively identified medications, such as digoxin, flecainide, and sotalol, there is no first-line drug treatment protocol established for the treatment of various types of fetal tachycardias.

Methods: We conducted a network meta-analysis using a Bayesian hierarchical framework to obtain a model for integrating both direct and indirect evidence. All tachycardia types (Total group), supraventricular tachycardia (SVT subgroup), atrial flutter (AF subgroup), hydrops subgroup, and non-hydrops subgroup fetuses were analyzed, and five first-line regimens were ranked according to treatment outcomes: digoxin monotherapy (D), flecainide monotherapy (F), sotalol monotherapy (S), digoxin plus flecainide combination therapy (DF), and digoxin plus sotalol combination therapy (DS). Effectiveness and safety were determined according to the cardioversion rate and intrauterine death rate.

Results: The pooled data indicated that DF combination therapy was always superior to D monotherapy, regardless of the tachycardia type or the presence of hydrops: Total, 2.44 (95% CrI: 1.59, 3.52); SVT, 2.77 (95% CrI: 1.59, 4.07); AF, 67.85 (95% CrI: 14.25, 168.68); hydrops, 6.03 (95% CrI: 2.54, 10.68); and non-hydrops, 5.06 (95% CrI: 1.87, 9.88). DF and F had a similar effect on control of fetal tachycardias. No significant differences were observed when comparing S, DS with D therapies across the subgroup analyses for the SVT, hydrops, and non-hydrops groups. No significant differences in mortality risks were among the various treatment regimens for the total group. And no significant differences were found in rates of intrauterine death rates at the same cardioversion amount.

Conclusion The flecainide monotherapy and combination of digoxin and flecainide should be considered the most superior therapeutic strategies for fetal tachycardia.

Systematic Review Registration: (https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=288997), identifier (288997).

Atypical fetal junctional ectopic tachycardia: a case report and literature review

Background

Junctional ectopic tachycardia (JET) is caused by ectopic rhythms, originating in the atrioventricular node, typically with heart rate between 200 and 250 bpm. Herein, we present a case of fetal JET with normal fetal heart rate and a review of nine cases.

Case presentation

A 32-year-old, gravida 2, para 1, woman in whom fetal JET could not be diagnosed prenatally because the fetal heart rate was within the normal range. The fetus was diagnosed with premature restriction of the foramen ovale, and a cesarean section was performed, owing to the right heart overload that was characterized by fetal ascites and abnormal fetal Doppler velocity. Postnatally, the female neonate was diagnosed with JET on a 12-lead electrocardiogram, which revealed a neonatal heart rate of 158 bpm with narrow QRS and atrioventricular dissociation. After failure to respond to amiodarone therapy, she was treated with flecainide, which controlled the JET rate from 120 to 150 bpm. Fetal tachycardia with ventriculo-atrial (VA) dissociation or 1:1 VA conduction with a shorter VA interval than that of atrioventricular reentrant tachycardia confirmed the diagnosis of fetal JET.

Conclusions

JET should be suspected even in the absence of tachycardia in patients with ductus venosus and pulmonary vein retrograde flow or tricuspid and mitral regurgitation without a cardiac anomaly, as tachycardia might sometimes be intermittent in cases of JET.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04655-6.

Arrhythmias in Pregnancy

Increasing maternal mortality and incidence of arrhythmias in pregnancy have been noted over the past 2 decades in the United States. Pregnancy is associated with a greater risk of arrhythmias, and patients with a history of arrhythmias are at significant risk of arrhythmia recurrence during pregnancy. The incidence of atrial fibrillation in pregnancy is rising. This review discusses the management of tachyarrhythmias and bradyarrhythmias in pregnancy, including management of cardiac arrest. Management of fetal arrhythmias are also reviewed. For patients without structural heart disease, β-blocker therapy, especially propranolol and metoprolol, and antiarrhythmic drugs, such as flecainide and sotalol, can be safely used to treat tachyarrhythmias. As a last resort, catheter ablation with minimal fluoroscopy can be performed. Device implantation can be safely performed with minimal fluoroscopy and under echocardiographic or ultrasound guidance in patients with clear indications for devices during pregnancy. Because of rising maternal mortality in the United States, which is partly driven by increasing maternal age and comorbidities, a multidisciplinary and/or integrative approach to arrhythmia management from the prepartum to the postpartum period is needed.

Association of Fetal Atrial Flutter with Neonatal Atrioventricular Re-entry Tachycardia Involving Accessory Pathway: A Link to be Remembered

To investigate prenatal and postnatal outcomes of atrial flutter and its association with the development of a second tachycardia, following restoration of sinus rhythm, in the fetus or newborn. This study is a retrospective review of all fetuses that presented with atrial flutter from January 2001 to December 2019 at the University Hospital of Wales, Cardiff, UK. The specific type of arrhythmia, its time of appearance and clinical characteristics, echocardiographic findings, medical management, and postnatal outcomes were evaluated. Sixteen fetuses were diagnosed with atrial flutter (AFL). Thirteen fetuses had persistent AFL and three fetuses had intermittent AFL. Seven patients had hydrops, of which one had Ebstein's anomaly and the other six had normal hearts. Three of the fetuses that presented with AFL were diagnosed at 20, 21, and 23 weeks' gestation and the remainder were diagnosed in the third trimester. Thirteen patients with AFL received antiarrhythmic drugs and three were delivered without any treatment. Five fetuses with AFL developed atrioventricular reciprocating tachycardia following DC cardioversion after birth, and four of them exhibited pre-excitation on the ECG. These five patients (31.3%) required postnatal antiarrhythmic treatment for up to 2 years. Pre-excitation disappeared in two patients during follow-up and two asymptomatic patients with neonatal pre-excitation required accessory pathway ablation. Fetal atrial flutter has a strong association with atrioventricular reciprocating tachycardia and ventricular pre-excitation in the neonatal period. Therefore, electrocardiograms should be carefully reviewed in newborns following the initial resolution of atrial flutter.

Incidence of atrial fibrillation in pregnancy and clinical significance: A meta-analysis

PURPOSE

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia worldwide, and is associated with increased morbidity and mortality. However, the incidence and maternal/fetal outcomes of AF in pregnancy remain unclear. This study's aims were to investigate the pooled incidence of AF in pregnant women and to assess maternal/fetal outcomes of AF in pregnancy.

MATERIAL AND METHODS

A literature search for studies that reported incidence of AF in pregnancy, was conducted using MEDLINE, EMBASE and Cochrane Database from inception through May 2018. Pooled incidence with 95%CI were calculated using a random-effect model. The protocol for this meta-analysis is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42018095955).

RESULTS

We identified 7 cohort studies including 301,638 pregnancies. The pooled estimated incidence of AF in pregnancy among women with no known heart disease, and those with structural heart disease was 0.3% (95%CI: 0.01%-40.6%) and 2.2% (95%CI: 0.96%-5.01%), respectively. Among women with known AF, the pooled estimated incidence of recurrent AF in pregnancy was 39.2% (95%CI: 16.9%-67.2%). The pooled estimated incidence of pre-eclampsia and congestive heart failure among pregnant patients with AF was 4.1% (95%CI: 2.1%-7.8%) and 9.6% (95%CI: 5.7%-15.9%), respectively. The pooled estimated incidence of fetal events including premature birth, small for gestational age, respiratory distress syndrome, intraventricular hemorrhage, death was 26.6% (95%CI: 20.4%-34.0%).

CONCLUSION

The overall estimated incidence of AF and recurrent AF during pregnancy is as high as 2.2% and 39.2%, respectively. AF during pregnancy may result in poor maternal and fetal outcomes.

Transplacental treatment of fetal tachycardia: A systematic review and meta-analysis

OBJECTIVE

Multiple transplacental medications can be used to treat fetal tachycardia. We sought to perform a systematic review and meta-analysis to determine whether digoxin, flecainide, or sotalol was the most efficacious therapy for converting fetal tachycardia to sinus rhythm.

METHOD

We performed a systematic review and meta-analysis to compare digoxin, flecainide, or sotalol as first-line therapy for fetal tachycardia. Studies were identified by a search of PubMed (Medline), Web of Science, and Scopus.

RESULTS

There were 21 studies included. Flecainide (OR: 1.4, 95% CI: 1.1-2.0, I²  = 60%, P = 0.03) and sotalol (OR:1.4, 95% CI:1.1-2.0, I²  = 30%, P = 0.02) were superior to digoxin for conversion of fetal tachycardia to sinus rhythm. In those with hydrops, the benefit over digoxin was more notable for both flecainide (OR: 5.0, 95% CI: 2.5-10.0, I²  = 0%, P < 0.001) and sotalol (OR: 2.5, 95% CI: 1.7-5.0, I²  = 0%, P < 0.001). When limited to atrioventricular reentrant tachycardia, flecainide was superior to digoxin (OR:1.7, 95% CI:1.1-3.3, I²  = 62%, P = 0.03) and sotalol (OR:1.3, 95% CI:1.1-1.7, I²  = 0%, P = 0.01).

CONCLUSION

Digoxin should not be first-line therapy for fetal tachycardia, particularly in the presence of hydrops fetalis. Flecainide should be the first-line therapy of choice in atrioventricular reentrant tachycardia. Further study may identify further sub-populations responding differently.

Clinical presentation, management, and postnatal outcomes of fetal tachyarrhythmias: A 10-year single-center experience

Background

Limited information is available regarding the prevalence and outcomes of fetal tachyarrhythmias from the developing countries.

Aims

This study aims to report referral patterns, management protocols, and pregnancy outcomes of fetuses with tachyarrhythmias reporting to a single center in South India.

Methods

All fetuses with documented sustained fetal tachyarrhythmia during the study period (2008-2017) were included. Arrhythmia characterization and hemodynamic evaluation were done using fetal echocardiography. Patients were grouped into supraventricular tachycardia (SVT) and atrial flutter (AF) groups. Patient characteristics, transplacental therapy (TPT), pregnancy, and postnatal outcomes were analyzed.

Results

Total of 19 fetuses included; 11 had SVT and 8 AF. Mean gestational age at referral was higher for AF (32.5 ± 3.2 vs. 29.6 ± 3.3 weeks; P = 0.05). Hydrops fetalis was present 8 (42%) fetuses; 4 in each group. TPT was instituted in 18 fetuses; 12 (66.7%) received combination therapy; 4 (21%) received direct fetal therapy. Eighteen fetuses (91%) were born alive with one intrauterine death in a fetus with SVT and severe hydrops. Seven (87.5%) fetuses with hydrops survived. Twelve patients (66.7%) were delivered in sinus rhythm. Six babies (33.3%) had tachycardia at birth requiring anti-arrhythmic therapy. All patients survived the neonatal period. Duration of trans-placental therapy (3.8 + 3.3 vs. 7.3 + 3.4 weeks) was shorter in the AF group.

Conclusions

Aggressive TPT using combination of drugs achieves excellent pregnancy and postnatal outcomes in fetuses with tachyarrhythmia. Early diagnosis and prompt referral before hemodynamic decompensation is critical for ensuring optimal outcomes.

First-Line Antiarrhythmic Transplacental Treatment for Fetal Tachyarrhythmia: A Systematic Review and Meta-Analysis

Background

There is no consensus on the most effective and best tolerated first‐line antiarrhythmic treatment for fetal tachyarrhythmia. The purpose of this systematic review and meta‐analysis was to compare the efficacy, safety, and fetal–maternal tolerance of first‐line monotherapies for fetal supraventricular tachycardia and atrial flutter.

Methods and Results

A comprehensive search of several databases was conducted through January 2017. Only studies that made a direct comparison between first‐line treatments of fetal tachyarrhythmia were included. Outcomes of interest were termination of fetal tachyarrhythmia, fetal demise, and maternal complications. Ten studies met inclusion criteria, with 537 patients. Overall, 291 patients were treated with digoxin, 137 with flecainide, 102 with sotalol, and 7 with amiodarone. Digoxin achieved a lower rate of supraventricular tachycardia termination compared with flecainide (odds ratio [OR]: 0.773; 95% confidence interval [CI], 0.605–0.987; I²=34%). In fetuses with hydrops fetalis, digoxin had lower rates of tachycardia termination compared with flecainide (OR: 0.412; 95% CI, 0.268–0.632; I²=0%). There was no significant difference in the incidence of maternal side effects between digoxin and flecainide groups (OR: 1.134; 95% CI, 0.129–9.935; I²=80.79%). The incidence of maternal side effects was higher in patients treated with digoxin compared with sotalol (OR: 3.148; 95% CI, 1.468–6.751; I²=0%). There was no difference in fetal demise between flecainide and digoxin (OR: 0.767; 95% CI, 0.140–4.197; I²=44%).

Conclusions

Flecainide may be more effective treatment than digoxin as a first‐line treatment for fetal supraventricular tachycardia.

Foetal tachyarrhythmia treatment remains challenging even if the vast majority of cases have a favourable outcome

AIM

The optimal treatment for foetal tachyarrhythmia remains controversial, and this study aimed to fill this gap in the knowledge.

METHODS

We retrospectively reviewed all cases of foetal tachyarrhythmia diagnosed at two tertiary foetal cardiology centres in Sweden from 1990 to 2012.

RESULTS

Of the 153 cases, 28% had atrial flutter (AF), 63% had atrioventricular reentrant tachycardia (AVRT) and 9% had other mechanisms. Hydrops was present in 45, less frequently in AF than in AVRT. Transplacental treatment was commenced in 99 and the rhythm normalised in two-thirds, without any significant difference in cardioversion rates between AF and AVRT cases or nonhydropic and hydropic foetuses. Sotalol treatment had a higher cardioversion rate than digoxin in AVRT (63% versus 33%, p < 0.05) but not in AF (57% versus 56%). Two or more drugs were used in 38%. Neonatal survival was 100% in nonhydropic and 84% in hydropic cases. After a median of eight years, 11/134 patients still had arrhythmias, one had died due to arrhythmia and another had undergone cardiac transplantation.

CONCLUSION

Transplacental treatment was frequently insufficient to obtain cardioversion in nonhydropic and hydropic foetuses, but all nonhydropic cases had favourable outcomes. Larger prospective studies are needed to optimise the treatment of cases with hydrops.

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.

Prenatal management and outcomes in mirror syndrome associated with twin-twin transfusion syndrome

OBJECTIVE

The aim of this article is to investigate the prevalence, clinical presentation, prenatal management, and prognosis of mirror syndrome associated with twin-twin transfusion syndrome (TTTS) treated by amnioreduction or selective fetocide.

METHOD

A retrospective study of twin pregnancies with TTTS was conducted. The prevalence of mirror syndrome, defined as severe maternal edema related to fetal hydrops and placental edema, was calculated for TTTS, and data on clinical characteristics, treatment, and outcomes of the patients were reviewed.

RESULTS

We observed mirror syndrome in 4.85% (5/103) of pregnancies with TTTS and 26.32% (5/19) of pregnancies with TTTS Stage IV. Most cases (4/5) of mirror syndrome associated with TTTS were diagnosed before 24 weeks of gestation. The patients manifested edema, anemia, hemodilution, and hypoproteinemia (5/5); proteinuria (4/5); complicated postpartum hemorrhage (4/5); and pulmonary edema and congestive heart failure (2/5). Maternal hemoglobin, hematocrit, and plasma protein dropped after amnioreduction. The perinatal survival rate at 28 days was 28.57% (2/7), and only one infant born after selective feticide survived beyond 18 months.

CONCLUSION

TTTS carries a high risk of mirror syndrome, a disease with significant materno-fetal mortality and morbidity. Amnioreduction alone or with selective feticide in mirror syndrome may transiently aggravate anemia and hemodilution and lead to severe maternal complications. © 2014 John Wiley & Sons, Ltd.

Sotalol as first-line treatment for fetal tachycardia and neonatal follow-up

OBJECTIVES

In fetal tachycardia, pharmacological therapy with digoxin, flecainide and sotalol has been reported to be effective. In a recent retrospective multicenter study, sotalol was considered to be less effective than the other drugs in treatment of fetal supraventricular tachycardia (SVT). The aim of this study was to re-evaluate the efficacy and safety of maternally administered sotalol in the treatment of fetal tachycardia.

METHODS

This was a retrospective review of the records of 30 consecutive fetuses with tachycardia documented on M-mode echocardiography between January 2004 and December 2010 at Wilhelmina Children's Hospital, a tertiary referral university hospital. Patients were subdivided into those diagnosed with supraventricular tachycardia and those with atrial flutter (AF) and presence of hydrops was noted. Other variables investigated included QTc interval measured on maternal electrocardiogram before and after initiation of antiarrhythmic therapy, fetal heart rhythm and heart rate pre- and postnatally, oral maternal drug therapy used, time to conversion to sinus rhythm (SR), percentage of fetuses converted following transplacental treatment, maternal adverse effects, presence or absence of tachycardia as noted on postnatal ECG, postnatal therapy or prophylaxis and neonatal outcome. Findings are discussed with reference to the literature.

RESULTS

A total of 28 patients (18 with SVT, 10 with AF) were treated with sotalol as first-line therapy. Fetal hydrops was present in six patients (five with SVT, one with AF). All hydropic patients converted antenatally to SR (67% with sotalol as a single-drug therapy, 33% after addition of flecainide). Of the non-hydropic patients, 91% converted to SR (90% with sotalol only, 10% after addition of flecainide or digoxin). In 9% (with AF) rate control was achieved. There was no mortality. No serious drug-related adverse events were observed. Postnatally, rhythm disturbances were detected in 10 patients, two of whom still had AF. In eight, SVT was observed within 3 weeks postnatally, and in five of these within 72 hours.

CONCLUSIONS

Sotalol can be recommended as the drug of first choice for treatment of fetal AF and has been shown to be an effective and safe first-line treatment option for SVT, at least in the absence of hydrops. Postnatal maintenance therapy after successful prenatal therapy is not necessarily indicated, as the risk of recurrence is low beyond 72 hours of age.

The pediatric cardiology pharmacopeia: 2013 update

The use of medications plays a pivotal role in the management of children with heart diseases. Most children with increased pulmonary blood flow require chronic use of anticongestive heart failure medications until more definitive interventional or surgical procedures are performed. The use of such medications, particularly inotropic agents and diuretics, is even more amplified during the postoperative period. Currently, children are undergoing surgical intervention at an ever younger age with excellent results aided by advanced anesthetic and postoperative care. The most significant of these advanced measures includes invasive and noninvasive monitoring as well as a wide array of pharmacologic agents. This review update provides a medication guide for medical practitioners involved in care of children with heart diseases.

Rapid control of foetal supraventricular tachycardia with digoxin and flecainide combination treatment

OBJECTIVES

To evaluate the efficacy of flecainide and digoxin combination in foetal supraventricular tachycardia.

SETTING

This study was carried out in a tertiary referral centre.

METHODS

We conducted a retrospective review of 29 patients diagnosed with supraventricular foetal tachycardia between 2001 and 2009. Mode of presentation, foetal cardiac function, maternal anti-arrhythmic serum levels, drug tolerance, and maternal electrocardiogram recordings were assessed. The postnatal outcome of each infant was also evaluated for tachycardia recurrence.

RESULTS

In all, 27 foetuses were treated with digoxin and flecainide combination, and two foetuses were delivered without any treatment. Of the 27 foetuses treated, six [corrected] had atrial flutter and the remaining 21 [corrected] had atrioventricular re-entry tachycardia. There were eight foetuses with hydrops (27%), of whom three had atrial flutter and five had atrioventricular re-entry tachycardia; 26 foetuses (96%) responded to flecainide and digoxin combination, with restoration of sinus rhythm in 22 (81.4%) and rate control in the other four. In one severely hydropic foetus, there was no response to treatment. In all, 26 treated infants were delivered alive, but one pregnancy was terminated for non-cardiac causes when the foetus was in sinus rhythm. There was no intrauterine death due to tachycardia. Although there were minor side effects to anti-arrhythmic medications, none of the pregnant women developed proarrhythmia.

CONCLUSION

Flecainide and digoxin combination treatment offers a safe and effective treatment for foetal supraventricular tachycardia with fast restoration of sinus rhythm.

Prenatal diagnosis, management and outcome of fetal dysrhythmia: a tertiary fetal medicine centre experience over an eight-year period

OBJECTIVE

To review the prenatal diagnosis, management and outcome of fetal dysrhythmia.

SUBJECTS AND METHODS

Prenatal diagnosis, management and outcomes of fetuses with dysrhythmia were reviewed retrospectively (01/01/1997 to 31/12/2004).

RESULTS

Over an 8-year period, 318 pregnant mothers were referred for assessment of suspected fetal dysrhythmias. Median gestation was 30 weeks (range 19-41). Fetal dysrhythmia was identified in 182 (57%) and classified as: (i) 126 atrial extrasystoles; (ii) 26 tachyarrhythmia, and (iii) 30 bradyarrhythmia. Of the fetuses with tachyarrhythmia, 23 had supraventricular tachycardia (SVT), 2 atrial flutter and 1 sinus tachycardia. One death associated with severe hydrops occurred in the tachyarrhythmia group. 19 cases of SVT were successfully treated in utero. Both cases of atrial flutter required direct current cardioversion in the neonatal period. In the bradyarrhythmia group, there were 15 isolated cases and 10 cases associated with congenital heart disease, with 73 and 20% survival, respectively.

CONCLUSIONS

Benign atrial extrasystoles are the commonest cause for referral and assessment of fetal dysrhythmia. The overall prognosis for SVT is good with the majority responding to transplacental therapy. In cases with congenital atrioventricular block, the outcome was less favourable, especially when the atrioventricular block was associated with congenital heart disease.

Prenatal pharmacotherapy for fetal anomalies: a 2011 update

Fetal therapy can be defined as any prenatal treatment administered to the mother with the primary indication to improve perinatal or long-term outcomes for the fetus or newborn. This review provides an update of the pharmacological therapies that are solely directed at the fetus with anomalies and outlines a future transcriptomic approach. Fetal anomalies targeted with prenatal pharmacotherapy are a heterogeneous group of structural, endocrine, and metabolic conditions, including congenital cystic adenomatoid malformation (CCAM), congenital adrenal hyperplasia, congenital heart block, fetal tachyarrhythmias, inborn errors of metabolism, fetal thyroid disorders, and polyhydramnios. To date, the majority of pharmacotherapies for fetal anomalies have been evaluated only in retrospective, uncontrolled studies. The way forward will be with an evidence-based approach to prenatal pharmacological interventions.

Perinatal management and long-term cardiac outcome in fetal arrhythmia

BACKGROUND

cardiac arrhythmias are commonly observed in the fetus, however, may have major consequences for fetal development and post natal life.

AIMS

to evaluate the perinatal management and cardiac outcome of fetuses with tachy- or bradyarrhythmia.

STUDY DESIGN

perinatal management, outcome and long-term cardiac follow-up were evaluated retrospectively in consecutive fetuses with cardiac arrhythmias.

RESULTS

forty-four fetuses were diagnosed: supraventricular tachycardia (SVT, n=28), atrial flutter (AF, n=7) and atrioventricular block (AVB, n=9). The overall incidence of cardiac anomalies was 18% mainly in the AVB group; hydrops was present in 34%. Direct or transplacental fetal anti-arrhythmic medication was given in 76%. Mortality was 6% in SVT/AF and 78% in the AVB group, respectively. AF resolved in all patients. In the SVT group, Wolff-Parkinson-White (WPW) syndrome was present in 21%, diagnosed at birth or later in life. After the age of one year about 90% of patients in the SVT group remained asymptomatic and free of drugs (median follow-up 76months).

CONCLUSIONS

mortality rate is low in patients with fetal SVT and AF but high in patients with AVB. Related morbidity includes WPW-syndrome and congenital cardiac anomalies. Electrocardiographic screening is recommended in all fetal SVT cases before adolescence since WPW-syndrome may occur later in life.

Perinatal isolated atrial flutter associated with maternal cocaine and opiate use in a late preterm infant

Atrial flutter is a serious form of neonatal tachyarrhythmia. Maternal drug use of cocaine and/or opiate is associated with central and autonomic nervous signs in fetuses and newborn infants. The fetal cardiovascular effects of cocaine and opiate exposure are not well characterized. We present the case of isolated atrial flutter in a late preterm infant who has been perinatally exposed to cocaine and opiate.

Diagnosis, clinical features, management, and post-natal follow-up of fetal tachycardias

OBJECTIVE

To evaluate the diagnosis, clinical features, management and post-natal follow-up in consecutive fetuses identified with tachycardia.

METHODS

We reviewed consecutive fetuses with tachycardia identified in a single tertiary institution between January, 2001, and December, 2008. We considered several options for management, including no treatment but close surveillance, trans-placental antiarrhythmic therapy in fetuses presenting prior to 36 weeks of gestation, and delivery and treatment as a neonate for fetuses presenting after 36 weeks of gestation. Data was gathered by a review of prenatal and postnatal documentation.

RESULTS

Among 29 fetuses with tachycardia, 21 had supraventricular tachycardia with 1 to 1 conduction, 4 had atrial flutter, 3 had atrial tachycardia, while the remaining fetus had ventricular tachycardia. Of the group, 8 fetuses (27.6%) were hydropic. Transplacental administration of antiarrhythmic drugs was used in just over half the fetuses, delivery and treatment as a neonate in one-quarter, and no intervention but close surveillance in one-sixth of the case. Twenty-six of 29 fetuses (89.7%) were born alive. Only patients with fetal hydrops suffered mortality, with 37.5% of this group dying, this being statistically significant, with the value of p equal to 0.03, when compared to non-hydropic fetuses. Only 3 patients (11.5%) were receiving antiarrhythmic prophylaxis beyond the first year of life.

CONCLUSION

A significant proportion of fetal tachycardias recognized before 36 weeks of gestation can be treated successfully by transplacental administration of antiarrhythmic drugs. Fetuses presenting after 36 weeks of gestation can be effectively managed postnatally. The long-term prognosis for fetuses diagnosed with tachycardia is excellent, with the abnormal rhythm resolving spontaneously during the first year of life in most of them.

Overview of fetal arrhythmias

PURPOSE OF REVIEW

Though fetal arrhythmias account for a small proportion of referrals to a fetal cardiologist, they may be associated with significant morbidity and mortality. The present review outlines the current literature with regard to the diagnosis and, in brief, some management strategies in fetal arrhythmias.

RECENT FINDINGS

Advances in echocardiography have resulted in significant improvements in our ability to elucidate the mechanism of arrhythmia at the bedside. At the same time, magnetocardiography is broadening our understanding of mechanisms of arrhythmia especially as it pertains to ventricular arrhythmias and congenital heart block. It provides a unique window to study electrical properties of the fetal heart, unlike what has been available to date. Recent reports of bedside use of fetal ECG make it a promising new technology. Fetal magnetocardiography is also developing. The underlying mechanisms resulting in immune-mediated complete heart block in a small subset of 'at-risk' fetuses is under investigation.

SUMMARY

There have been great strides in noninvasive diagnosis of fetal arrhythmias. However, we still need to improve our knowledge of the electromechanical properties of the fetal heart as well as the mechanisms of arrhythmia to further improve outcomes. Multiinstitutional collaborative studies are needed to help answer some of the questions regarding patient, drug selection and management algorithms.

Fetal dysrhythmias

Fetal cardiac dysrhythmias are potentially life-threatening conditions. However, intermittent extrasystoles, which are frequently encountered in clinical practice, do not require treatment. Sustained forms of brady- and tachyarrhythmias might require fetal intervention. Fetal echocardiography is essential not only to establish the diagnosis but also to monitor fetal response to therapy. In the last decade, improvements in ultrasound methodology and new diagnostic tools have contributed to better diagnostic accuracy and to a greater understanding of the electrophysiological mechanisms involved in fetal cardiac dysrhythmias. The most common form of supraventricular tachycardia - that caused by an atrioventricular re-entry circuit - should be differentiated from other forms of tachyarrhythmias, such as atrial flutter and atrial ectopic tachycardia. Ventricular tachycardia is rare in the fetus. Sustained tachycardias, intermittent or not, might be associated with the development of congestive heart failure and hydrops fetalis. Prompt treatment with either anti-arrhythmic drugs or delivery must be considered. Persistent fetal bradycardias associated with complete heart block are also potentially dangerous, whereas bradyarrhythmia due to blocked ectopy is well tolerated in pregnancy. Heart block can be associated with maternal anti-Ro/La autoantibodies or develop in fetuses with left atrial isomerism or with malformations involving the atrioventricular junction. The treatment of fetuses with immune-mediated heart block remains debatable. The use of antenatal steroid therapy is not widely accepted and there is concern over the risks and benefits of its use in the fetus. Direct fetal cardiac pacing has rarely been attempted.

Drug management of fetal tachyarrhythmias: are we ready for a systematic and evidence-based approach?

Fetal tachyarrhythmias are a life-threatening condition complicating a small proportion of normal pregnancies. Despite major advances in the (intrauterine) pharmacologic treatment of these arrhythmias over the last years major uncertainties remain. Among these are controversies in the choice of agents in relation to arrhythmia type, and timing and duration of treatment. Currently, no evidence-based approach to the management of fetal tachyarrhythmias is available. An international registry is proposed as an important step toward obtaining the necessary data to develop evidence-based management strategies.

Detection and management of life threatening arrhythmias in the perinatal period

The management of tachyarrhythmias and bradyarrythmias in the fetus requires a team approach with careful monitoring of fetal well-being as well as care in establishing a precise diagnosis with use of m-mode and Doppler echocardiography to determine the atrial and ventricular rate. A persistent fetal heart rate less than 80 beats per minute (bpm) suggests complete atrioventricular block. A persistent fetal heart rate over 180 bpm suggests pathological tachycardia, most of which are a supraventricular tachycardia mediated via an accessory pathway. However, around 20% are due to atrial flutter, and this review highlights why medical management should be different for these cases, and for those with hydrops or cardiac failure. It also illustrates which fetus or infant may be at particular risk, and illustrates key features in their management before and after birth.

Fetal and maternal magnetocardiography during flecainide therapy for supraventricular tachycardia

BACKGROUND

Fetal magnetocardiography is a noninvasive technique capable of identifying fetal arrhythmias and can simultaneously characterize the cardiac rhythm of the mother and fetus.

CASES

Three patients, two singleton pregnancies and one twin pregnancy, were admitted for evidence of fetal supraventricular tachycardia. Fetal magnetocardiography was used to monitor the effects of flecainide therapy on the fetus and mother. Two singleton pregnancy fetuses showed improved heart rate and cardiac rhythm within 1 week of the initial dosing. Maintenance dosages controlled the conditions thereafter. Flecainide slowed the supraventricular tachycardia in the twin subject, but magnetocardiography revealed maternal adverse effects necessitating termination of flecainide therapy.

CONCLUSION

Magnetocardiography is a valuable tool for rhythm diagnosis and for monitoring the maternal and fetal cardiac rhythms in a patient undergoing flecainide therapy for fetal supraventricular tachycardia.

Cardiac arrhythmias in the fetus and newborn

Arrhythmias are potentially life-threatening problems in the fetus and newborn. Appropriate management depends on accurate diagnosis. Atrioventricular re-entry is the most common type of supraventricular tachycardia in both the fetus and newborn. It should be distinguished from other types of tachycardia - such as atrial flutter, atrial ectopic tachycardia, permanent junctional re-entry tachycardia, and ventricular tachycardia. Neonatal and fetal bradycardias are less common clinical problems. Sustained bradycardia is most often caused by complete atrioventricular block. It can be mimicked by the more common but benign occurrence of non-conducted atrial premature beats.

Amiodarone in Treatment of Fetal Supraventricular Tachycardia

We report a case of nonimmune hydrops fetalis detected at 32 weeks of gestation. Fetal heart rate was 300 beats per minute. Ultrasound and fetal Doppler echocardiography showed it to be due to supraventricular tachycardia (SVT). Following failed maternal therapy with digoxin alone, amiodarone with digoxin was used. Conversion to sinus rhythm and resolution of hydrops followed this treatment. Since there is no ideal treatment protocol for these cases at present, we reviewed reports of transplacental treatment of SVT.

Fetal brady- and tachyarrhythmias: new and accepted diagnostic and treatment methods

Sustained bradyarrhythmias are typically the result of symptomatic sinus bradycardia, atrial bigeminy or complete atrioventricular (AV) block. Fetal tachyarrhythmias relate to sinus tachycardia, atrial flutter and supraventricular tachycardia as the main aetiology. Ultrasound is essential to understand the underlying arrhythmia mechanism, to study the impact on cardiac function, to exclude cardiac defects or tumours, and to survey the fetal heart rate and well-being, e.g. during anti-arrhythmic treatment. Based on retrospective studies, several more or less safe, effective and well-tolerated anti-arrhythmic agents are currently available for the treatment of atrial and supraventricular tachycardia. Isolated congenital complete AV block is mainly related to maternal anti-Ro/La auto-antibodies. The rationale to treat a fetus at this irreversible stage of AV nodal damage is primarily to mitigate or prevent concomitant myocardial inflammation and to augment cardiac output. A recently published study demonstrated a significant improved outcome with transmaternal dexamethasone and beta-stimulation.

Prenatal diagnosis of fetal arrhythmias

Life-threatening fetal arrhythmias are rare and warrant sophisticated specialty prenatal care, often provided by maternal-fetal medicine obstetricians, and pediatric and adult cardiologists. This medical field is in quick transition, and new methods of diagnosis and treatment of the fetus with arrhythmias are emerging. In this article, the mechanisms of arrhythmias are presented in light of recent progress in the new field of fetal electrophysiology. Treatments are reviewed with recommendations based on the small number of series of fetal tachycardia and fetal atrioventricular (AV) block drug treatment strategies published to date. Finally, a summary of areas of potential future research is provided.

Intrauterine therapy for fetal supraventricular tachycardia in a twin pregnancy

A case of a twin pregnancy in which one fetus developed hydrops secondary to supraventricular tachycardia was detected at 21 weeks' gestation. Transplacental digoxin therapy successfully converted the supraventricular tachycardia to a normal sinus rhythm without evidence of maternal or fetal side-effects. The pregnancy proceeded to term and elective cesarean section was carried out at 37 weeks' gestation.

Neonatal intractable atrial flutter successfully treated with intravenous flecainide

We present a neonatal case with intractable atrial flutter that did not respond to digitalization and electrical cardioversion. Intravenous flecainide administration completely resolved the atrial flutter. Proarrhythmic effects were not induced by flecainide administration. Although the efficacy of flecainide for atrial flutter during the infantile or childhood period is low, intravenous flecainide is worth consideration as a treatment for atrial flutter, even in intractable cases as described here, during the neonatal period.

Treatment of fetal tachycardia with sotalol: transplacental pharmacokinetics and pharmacodynamics

OBJECTIVES

The aim of this study was to investigate the pharmacokinetics and pharmacodynamics of sotalol in the treatment of fetal tachycardia.

BACKGROUND

Maternally administered, intrauterine therapy of fetal tachycardia is dependent on the transplacental passage of the antiarrhythmic agent.

METHODS

In a prospective study of patients treated for fetal tachycardia with sotalol, concentrations of sotalol were determined in maternal and umbilical blood and in amniotic fluid, and the relationship between these concentrations and the occurrence of conversion to sinus rhythm was investigated.

RESULTS

Eighteen fetal patients were studied, nine with atrial flutter and nine with supraventricular tachycardia. Fourteen were treated with sotalol; 13 converted to sinus rhythm, of whom 2 relapsed. There was one intrauterine death. Four patients were treated with sotalol and digoxin, of whom two were treated successfully. Mean birth weight was 3,266 g. The daily maternal sotalol dose was linearly related to the maternal plasma concentration. The mean fetal/maternal sotalol plasma concentration was 1.1 (range 0.67 to 2.87, SD 0.63), and the mean amniotic fluid/fetal blood ratio of sotalol was 3.2 (range 1.28 to 5.8, SD 1.4). The effectiveness of sotalol therapy could not be extrapolated from maternal blood levels.

CONCLUSIONS

Sotalol is a potent antiarrhythmic agent in the treatment of fetal tachycardia. The placental transfer is excellent. Sotalol accumulates in amniotic fluid but not in the fetus itself. Therefore it seems that renal excretion in the fetus is efficient and greater than the oral absorption by fetal swallowing. The maternal blood level is not a reliable predictor of the chances of success of therapy. Sotalol is not associated with fetal growth restriction.

Review of diagnosis, treatment, and outcome of fetal atrial flutter compared with supraventricular tachycardia

OBJECTIVE

To review the diagnosis, treatment, and outcome of fetal atrial flutter compared with supraventricular tachycardia.

DESIGN

Retrospective review of published reports: 11 papers about fetal tachyarrhythmia published between 1991 and 2002 were selected for review.

MAIN OUTCOME MEASURES

All selected studies were analysed for the type of arrhythmia, degree of atrioventricular block in atrial flutter, occurrence of hydrops fetalis, gestational age at diagnosis, first and second line drug treatment, associated cardiac and extracardiac malformations, and mortality of the fetuses.

RESULTS

Atrial flutter accounted for 26.2% of all cases of fetal tachyarrhythmias, and supraventricular tachycardia for 73.2%. Hydrops fetalis was reported in 38.6% and 40.5% of fetuses with atrial flutter and supraventricular tachycardia, respectively (NS). Hydropic fetuses with atrial flutter had higher ventricular rates (median 240 beats/min, range 240-300) than non-hydropic fetuses (220 beats/min, range 200-310) (p = 0.02), whereas the atrial rates were not significantly different (median 450 beats/min, range 370-500). Digoxin treatment resulted in a higher conversion rate in non-hydropic fetuses with fetal tachyarrhythmias than in hydropic fetuses (p < 0.001). The overall mortality of atrial flutter was similar to that of supraventricular tachycardia, at 8.0% v 8.9% (p = 0.7).

CONCLUSIONS

The prevalence of hydrops fetalis did not differ in fetal atrial flutter and supraventricular tachycardia with 1:1 conduction. There was no difference between the response rate to digoxin in fetus with atrial flutter or supraventricular tachycardia. Mortality was similar in the two types of tachyarrhythmia.

Fetal supraventricular tachycardia diagnosed and treated at 13 weeks of gestation: a case report

Supraventricular tachycardia (SVT) is the most commonly encountered clinically significant tachycardia in the fetus. When SVT is sustained, congestive heart failure and fetal hydrops may ensue, due to both systolic and diastolic dysfunction. Sonographic diagnosis is usually incidental during the second or third trimester. Treatment goals are cardioversion to sinus rhythm and reversal of cardiac dysfunction. We describe a case of fetal SVT diagnosed at 13 weeks of gestation. Treatment with digoxin and flecainide was successful; the heart rate returned to sinus rhythm within one day, and fetal hydrops resolved within 8 days of treatment. We suspect that as more first-trimester examinations are performed, more cases with SVT will be diagnosed. We discuss the treatment protocol, and suggest that co-administration of two drugs that act synergistically may be more efficient than monotherapy, which is currently used as the first line of treatment. In addition, we discuss the potentially deleterious effect of heart failure encountered at an early developmental stage on the central nervous system. More data need to be collected in order to substantiate a clear recommendation regarding optimal management.

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.

Fetal cardiology

A systematic approach to examination of the fetal heart will enhance the detection of structural cardiac abnormalities and will enable an accurate diagnosis of congenital heart disease to be made. Once an abnormality has been detected appropriate counselling must be provided and adequate support given to the parents. Associated extracardiac abnormalities should be sought for, and plans for the remainder of pregnancy, delivery and postnatal management should be made using a team approach. In cases resulting in termination of pregnancy, permission for autopsy should be sought to confirm the ultrasound diagnosis. Although in-utero therapy is available for some forms of fetal arrhythmia and a few limited cases of structural heart disease, this should be conducted in tertiary centres.