Postnatal outcome in patients with fetal tachycardia

Pharmacological Management of Cardiac Arrhythmias in the Fetal and Neonatal Periods: A Scientific Statement From the American Heart Association: Endorsed by the Pediatric & Congenital Electrophysiology Society (PACES)

Disorders of the cardiac rhythm may occur in both the fetus and neonate. Because of the immature myocardium, the hemodynamic consequences of either bradyarrhythmias or tachyarrhythmias may be far more significant than in mature physiological states. Treatment options are limited in the fetus and neonate because of limited vascular access, patient size, and the significant risk/benefit ratio of any intervention. In addition, exposure of the fetus or neonate to either persistent arrhythmias or antiarrhythmic medications may have yet-to-be-determined long-term developmental consequences. This scientific statement discusses the mechanism of arrhythmias, pharmacological treatment options, and distinct aspects of pharmacokinetics for the fetus and neonate. From the available current data, subjects of apparent consistency/consensus are presented, as well as future directions for research in terms of aspects of care for which evidence has not been established.

Outcome of Fetal Dysrhythmias with and without Extracardiac Anomalies

Fetal dysrhythmias are common abnormalities, which can be categorized into three types: rhythm irregularities, tachyarrhythmias, and bradyarrhythmias. Fetal arrhythmias, especially in high-risk pregnancies, require special monitoring and treatment. The aim of this study was to assess the stillbirth and early and late neonatal mortality rates for pregnancies complicated by fetal dysrhythmias from one single tertiary referral center from 2000 to 2022. Of the 1018 fetuses with congenital heart disease, 157 (15.42%) were evaluated in this analysis. Seventy-four (46.7%) fetuses had bradyarrhythmias, 51 (32.5%) tachyarrhythmias, and 32 (20.4%) had rhythm irregularities. Additional structural heart defects were detected in 40 (25.3%) fetuses and extracardiac anomalies in 29 (18.4%) fetuses. Thirteen (8.2%) families opted for termination of the pregnancy. Eleven (7.6%), out of 144 continued pregnancies ended in spontaneous intrauterine fetal death (IUFD). Neonatal death was observed in nine cases (5.7%), whereas three (1.9%) died within the first 7 days of life. Although most intrauterine fetal deaths occurred in pregnancies with fetal bradyarrhythmia, neonatal death was observed more often in fetuses with tachyarrhythmia (8.5%). The presence of extracardiac anomalies, congenital heart disease (CHD), and Ro-antibodies are predictive factors for the occurrence of IUFD. Rhythm irregularities without any other risk factor do not present higher risks of adverse perinatal outcome.

Neurodevelopmental outcome after antenatal therapy for fetal supraventricular tachyarrhythmia: 3-year follow-up of multicenter trial

OBJECTIVES

Although many studies have supported the efficacy of transplacental treatment for fetal supraventricular tachyarrhythmia, the long-term neurodevelopmental outcome after antenatal antiarrhythmic treatment is not well understood. The aim of this study was to investigate the prognosis and neurodevelopmental outcome at 36 months of corrected age and the incidence of tachyarrhythmia after birth, following protocol-defined antenatal therapy for fetal supraventricular tachyarrhythmia.

METHODS

This was a 3-year follow-up study of a multicenter trial that evaluated the efficacy and safety of protocol-defined transplacental treatment for fetal supraventricular tachycardia (SVT) and atrial flutter (AFL). The primary endpoints were mortality and neurodevelopmental impairment (NDI) at 36 months of corrected age. NDI was defined as any of the following outcomes: cerebral palsy, bilateral blindness, bilateral deafness or neurodevelopmental delay. Neurodevelopmental delay was evaluated using appropriate developmental quotient scales, mainly the Kyoto Scale of Psychological Development, or examination by pediatric neurologists. The detection rate of tachyarrhythmia at birth and at 18 and 36 months of corrected age was also evaluated as the secondary endpoint. In addition, the association of NDI at 36 months with perinatal and postnatal factors was analyzed.

RESULTS

Of 50 patients enrolled in the original trial, one withdrew consent and in two there was fetal death, leaving 47 patients available for enrollment in this follow-up study. Of these, 45 cases were available for analysis after two infants were lost to follow-up. The mortality rate was 2.2% (1/45) during a median follow-up of 3.2 (range, 2.1-9.4) years. The infant died at the age of 2.1 years. Another infant had missing neurodevelopmental assessment data. In the remaining 43 infants, at 36 months of corrected age, NDI was detected in 9.3% (4/43) overall and in two of three (66.7%) cases with fetal hydrops with subcutaneous edema. Cerebral palsy was noted in two infants with severe subcutaneous edema or ascites at an early gestational age. Neurodevelopmental delay was found in two infants with severe congenital abnormalities (one with tuberous sclerosis and the other with heterotaxy syndrome). Tachyarrhythmia was present in 31.9% (15/47) cases in the neonatal period and decreased to 8.9% (4/45) and 4.5% (2/44) at 18 and 36 months of corrected age, respectively. The median ventricular rate at diagnosis was significantly higher in infants with NDI compared to those without (265 vs 229 bpm; P = 0.003). In infants with NDI, compared to those without, fetal hydrops with subcutaneous edema at diagnosis was more common (50.0% vs 2.6%; P = 0.019) and the duration of fetal effusion was longer (median, 10.5 vs 0 days; P = 0.013). Postnatal arrhythmia and physical development abnormalities were not associated with NDI.

CONCLUSIONS

This multicenter 3-year follow-up study is the first to demonstrate the long-term mortality and morbidity of infants born following protocol-defined transplacental treatment for fetal SVT and AFL. NDI was associated with the presence of fetal hydrops with subcutaneous edema at diagnosis and longer duration of fetal effusion. Neurodevelopmental delay was detected only in infants with severe congenital abnormalities. Therefore, in infants that have undergone antenatal treatment for fetal tachyarrhythmia and in which there are no comorbidities, the risk of NDI is low. However, in those with fetal hydrops with subcutaneous edema and/or associated severe congenital abnormalities, the risk for long-term neurologic morbidity might be considered somewhat increased. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Frequency-Based Maternal Electrocardiogram Attenuation for Fetal Electrocardiogram Analysis

Fetal electrocardiogram (ECG) waveform analysis along with cardiac time intervals (CTIs) measurements are critical for the management of high-risk pregnancies. Currently, there is no system that can consistently and accurately measure fetal ECG. In this work, we present a new automatic approach to attenuate the maternal ECG in the frequency domain and enhance it with measurable CTIs. First, the coherent components between the maternal ECG and abdominal ECG were identified and subtracted from the latter in the frequency domain. The residual was then converted into the time domain using the inverse Fourier transform to yield the fetal ECG. This process was improved by averaging multiple beats. Two fetal cardiologists, blinded to the method, assessed the quality of fetal ECG based on a grading system and measured the CTIs. We evaluated the fetal ECG quality of our method and time-based methods using one synthetic dataset, one human dataset available in the public domain, and 37 clinical datasets. Among the 37 datasets analyzed, the mean average (± standard deviation) grade was 3.49 ± 1.22 for our method vs. 2.64 ± 1.26 for adaptive interference cancellation (p-value < 0.001), thus showing the frequency-based fetal ECG extraction was the superior method, as assessed from our clinicians' perspectives. This method has the potential for use in clinical settings.

Etiology and outcome of non-immune hydrops fetalis in relation to gestational age at diagnosis and intrauterine treatment

OBJECTIVE

To determine the etiology and outcome of non-immune hydrops fetalis (NIHF) according to gestational age at diagnosis and intrauterine treatment.

STUDY DESIGN

A total of 122 NIHF cases were included. Medical records and ultrasonographic images were reviewed. The etiology, outcome, and intrauterine treatment were assessed.

RESULTS

The etiology was determined in 100 cases, and Hb Bart's disease was the most common. Two cases each of homozygous Southeast Asian ovalocytosis (SAO) and hemoglobin Constant Spring (Hb CS) were found. NIHF diagnosed in early gestation (<24 weeks) had a higher rate of chromosomal abnormalities and fetal demise. Intrauterine treatment was given in 18 cases, and 50% had successful live births.

CONCLUSION

Hb Bart's disease was the most common cause of NIHF. SAO and Hb CS were associated with hydrops. NIHF in gestational age <24 weeks was associated with chromosomal abnormalities and fetal demise. Intrauterine treatment should be offered in selected cases.

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.

Fetal Tachycardia in the Delivery Room: Fetal Distress, Supraventricular Tachycardia, or Both?

Background  Supraventricular tachycardia (SVT) is seldom considered a cause for fetal tachycardia; commoner etiologies including maternal fever and fetal distress are usually envisaged. Fetal arrhythmia can be missed as a diagnosis, potentially leading to suboptimal management. Cases  Three cases are described where detection of fetal tachycardia >200 beats per minute (bpm) at 36, 40, and 38 weeks gestation resulted in emergency cesarean section for presumed fetal distress. Retrospective review of the cardiotocograph in two cases revealed baseline heart rates 120 to 160 bpm, with loss of trace associated with auscultated rates over 200 bpm. The diagnosis of SVT was not initially considered and made later when the infants required cardioversion at the age of 3 weeks, 2 days, and 8 days, respectively. The 36-week infant required noninvasive ventilation for prematurity. Conclusion  SVT should be actively considered in the differential diagnosis of fetal tachycardia. Unrecognized fetal SVT may result in avoidable caesarean for suspected fetal distress, with potential prematurity-related problems. The cardiotocograph can be helpful if showing contact loss associated with rapid heart rate auscultation. The antenatal detection of fetal SVT is important as it can allow anticipation and prevention of neonatal SVT, which is potentially life-threatening if not detected and treated promptly.

Fetal Atrial Ectopic Rhythm Detected Using Handheld Doppler

Atrial ectopic rhythm is one of the most common fetal arrhythmias that can present during the prenatal period. Detection of fetal arrhythmia can be made by auscultating fetal heart rate and rhythm using a fetal handheld Doppler, and this can be done even in a resource-limited setting. The finding of an abnormal fetal heart rate and rhythm should prompt early referral to a pediatric cardiologist, as this may improve clinical outcomes. We present a case of atrial ectopic rhythm detected in utero using a handheld Doppler.

Low mortality in fetal supraventricular tachycardia: Outcomes in a 30-year single-institution experience

OBJECTIVES

To describe a single institutional experience managing fetuses with supraventricular tachycardia (SVT) and to identify associations between patient characteristics and fetal and postnatal outcomes.

BACKGROUND

Sustained fetal SVT is associated with significant morbidity and mortality if untreated, yet the optimal management strategy remains unclear.

METHODS

Retrospective cohort study including fetuses diagnosed with sustained SVT (>50% of the diagnostic echocardiogram) between 1985 and 2018. Fetuses with congenital heart disease were excluded.

RESULTS

Sustained SVT was diagnosed in 65 fetuses at a median gestational age of 30 weeks (range, 14-37). Atrioventricular re-entrant tachycardia and atrial flutter were the most common diagnoses, seen in 41 and 16 cases, respectively. Moderate/severe ventricular dysfunction was present in 20 fetuses, and hydrops fetalis was present in 13. Of the 57 fetuses initiated on transplacental drug therapy, 47 received digoxin first-line, yet 39 of 57 (68%) required advanced therapy with sotalol, flecainide, or amiodarone. Rate or rhythm control was achieved in 47 of 57 treated fetuses. There were no cases of intrauterine fetal demise. Later gestational age at fetal diagnosis (odds ratio [OR], 1.1, 95% confidence interval [CI], 1.01-1.2, P = .02) and moderate/severe fetal ventricular dysfunction (OR, 6.1, 95% CI, 1.7-21.6, P = .005) were associated with postnatal SVT. Two postnatal deaths occurred.

CONCLUSIONS

Fetuses with structurally normal hearts and sustained SVT can be effectively managed with transplacental drug therapy with minimal risk of intrauterine fetal demise. Treatment requires multiple antiarrhythmic agents in over half of cases. Later gestational age at fetal diagnosis and the presence of depressed fetal ventricular function, but not hydrops, predict postnatal arrhythmia burden.

Feasibility of Non-invasive Fetal Electrocardiographic Interval Measurement in the Outpatient Clinical Setting

Non-invasive fetal electrocardiography (ECG) is a promising method for evaluating fetal cardiac electrical activity. Despite advances in fetal ECG technology, its ability to provide reliable, interpretable results in a typical outpatient fetal cardiology setting remains unclear. We sought to determine the feasibility of measuring standard ECG intervals in an outpatient fetal cardiology practice using an abdominal fetal ECG device that employs blind source separation with reference, an innovative signal-processing technique for fetal ECG extraction. Women scheduled for clinically indicated outpatient fetal echocardiogram underwent 10 min of fetal ECG acquisition from the maternal abdomen using specialized gel electrodes. A bedside laptop computer performed fetal ECG extraction, allowing real-time visualization of fetal and maternal ECG signals. Offline post-processing of 1 min of recorded data yielded fetal P-wave duration, PR interval, QRS duration, RR interval, QT interval, and QTc. Fifty-five fetuses were studied with gestational age 18-37 weeks, including 13 with abnormal fetal echocardiogram findings and three sets of twins. Interpretable results were obtained in 91% of fetuses, including 85% during the vernix period and 100% of twin fetuses. PR interval and RR interval of 18-24 week gestation fetuses were significantly shorter than those with gestational age 25-31 and 32-37 weeks. Of the six fetuses with abnormal rhythms on fetal echocardiogram, fetal ECG tracing was interpretable in five and matched the rhythm noted on fetal echocardiogram. Abdominal fetal ECG acquisition is feasible for arrhythmia detection and ECG interval calculation in a routine clinical setting.

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.

Postnatal Outcomes of Fetal Supraventricular Tachycardia: a Multicenter Study

Supraventricular tachycardia (SVT), the most common fetal tachycardia, can be difficult to manage in utero. We sought to better understand predictors of the postnatal clinical course in neonates who experienced fetal SVT. We hypothesized that fetuses with hydrops or those with refractory SVT (failure of first-line SVT therapy) are more likely to experience postnatal SVT. This was a retrospective multicenter cohort study of subjects diagnosed with fetal SVT between 2006 and 2014. Fetuses with structural heart disease were excluded. Descriptive comparative statistics and univariate analysis with logistic regression were utilized to determine factors that most strongly predicted postnatal SVT and preterm delivery. The cohort consisted of 103 subjects. Refractory SVT was found in 37% (N = 38) of the cohort with this group more likely to be delivered prematurely (median = 36 vs. 37.5 weeks, p = 0.04). Refractory SVT did not increase the risk of postnatal SVT (p = 0.09). Postnatal SVT was seen in 61% (N = 63). Of those, 68% (N = 43) had postnatal SVT at ≤2 days of age. Postnatal SVT was associated with a later fetal SVT diagnosis (median = 30 vs. 27.5 weeks, p = 0.006). We found a strong correlation between postnatal SVT and later gestational age at fetal SVT diagnosis. Subjects with refractory SVT or hydrops did not have a higher risk of postnatal SVT. We propose strong consideration for term delivery in the absence of significant clinical compromise. Further studies to assess whether outcomes vary for preterm delivery versus expectant management in those with refractory SVT should be performed.

Pharmacological Therapy of Tachyarrhythmias During Pregnancy

Tachyarrhythmias are the most frequently observed cardiac complications during pregnancy. The majority of these maternal and foetal arrhythmias are supraventricular tachyarrhythmias; ventricular tachyarrhythmias are rare. The use of anti-arrhythmic drugs (AADs) during pregnancy is challenging due to potential foetal teratogenic effects. Maintaining stable and effective therapeutic maternal drug levels is difficult due to haemodynamic and metabolic alterations. Pharmacological treatment of tachyarrhythmias is indicated in case of maternal haemodynamic instability or hydrops fetalis. Evidenc e regarding the efficacy and safety of AAD therapy during pregnancy is scarce and the choice of AAD should be based on individual risk assessments for both mother and foetus. This review outlines the current knowledge on the development of tachyarrhythmias during pregnancy, the indications for and considerations of pharmacological treatment and its potential side-effects.

The fetal brain sparing response to hypoxia: physiological mechanisms

How the fetus withstands an environment of reduced oxygenation during life in the womb has been a vibrant area of research since this field was introduced by Joseph Barcroft, a century ago. Studies spanning five decades have since used the chronically instrumented fetal sheep preparation to investigate the fetal compensatory responses to hypoxia. This defence is contingent on the fetal cardiovascular system, which in late gestation adopts strategies to decrease oxygen consumption and redistribute the cardiac output away from peripheral vascular beds and towards essential circulations, such as those perfusing the brain. The introduction of simultaneous measurement of blood flow in the fetal carotid and femoral circulations by ultrasonic transducers has permitted investigation of the dynamics of the fetal brain sparing response for the first time. Now we know that major components of fetal brain sparing during acute hypoxia are triggered exclusively by a carotid chemoreflex and that they are modified by endocrine agents and the recently discovered vascular oxidant tone. The latter is determined by the interaction between nitric oxide and reactive oxygen species. The fetal brain sparing response matures as the fetus approaches term, in association with the prepartum increase in fetal plasma cortisol, and treatment of the preterm fetus with clinically relevant doses of synthetic steroids mimics this maturation. Despite intense interest into how the fetal brain sparing response may be affected by adverse intrauterine conditions, this area of research has been comparatively scant, but it is likely to take centre stage in the near future.

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.

Tachycardia in the Neonate

Atrial flutter (AFL) is the second most common type of tachyarrhythmia in the fetus and neonate. An atrial rate of 240 to 360 beats per minute, 2:1 atrioventricular conduction, and a "saw tooth" appearance on electrocardiogram (ECG) are characteristic. On echocardiogram, bilateral atrial dilatation is the most common finding. Treatment is dependent on the severity of symptoms; delivery is usually indicated in the case of fetal heart failure or hydrops fetalis, whereas postnatal AFL is most commonly treated with direct current cardioversion (DCC). This article presents an illustrative case in which the patient presented antenatally via abnormal nonstress testing and subsequent fetal echocardiogram that was concerning for AFL. Postnatal ECG confirmed this diagnosis and the patient received DCC on the day of birth, followed by digoxin and propranolol as maintenance therapy.

Society for maternal-fetal medicine (SMFM) clinical guideline #7: nonimmune hydrops fetalis

OBJECTIVE

Nonimmune hydrops is the presence of ≥2 abnormal fetal fluid collections in the absence of red cell alloimmunization. The most common etiologies include cardiovascular, chromosomal, and hematologic abnormalities, followed by structural fetal anomalies, complications of monochorionic twinning, infection, and placental abnormalities. We sought to provide evidence-based guidelines for the evaluation and management of nonimmune hydrops fetalis.

METHODS

A systematic literature review was performed using MEDLINE, PubMed, EMBASE, and Cochrane Library. The search was restricted to English-language articles published from 1966 through June 2014. Priority was given to articles reporting original research, although review articles and commentaries also were consulted. Abstracts of research presented at symposia and scientific conferences were not considered adequate for inclusion in this document. Evidence reports and guidelines published by organizations or institutions such as the National Institutes of Health, Agency for Health Research and Quality, American Congress of Obstetricians and Gynecologists, and Society for Maternal-Fetal Medicine were also reviewed, and additional studies were located by reviewing bibliographies of identified articles. Grading of Recommendations Assessment, Development, and Evaluation methodology was employed for defining strength of recommendations and rating quality of evidence. Consistent with US Preventive Task Force guidelines, references were evaluated for quality based on the highest level of evidence.

RESULTS AND RECOMMENDATIONS

Evaluation of hydrops begins with an antibody screen (indirect Coombs test) to determine if it is nonimmune, detailed sonography of the fetus(es) and placenta, including echocardiography and assessment for fetal arrhythmia, and middle cerebral artery Doppler evaluation for anemia, as well as fetal karyotype and/or chromosomal microarray analysis, regardless of whether a structural fetal anomaly is identified. Recommended treatment depends on the underlying etiology and gestational age; preterm delivery is recommended only for obstetric indications including development of mirror syndrome. Candidates for corticosteroids and antepartum surveillance include those with an idiopathic etiology, an etiology amenable to prenatal or postnatal treatment, and those in whom intervention is planned if fetal deterioration occurs. Such pregnancies should be delivered at a facility with the capability to stabilize and treat critically ill newborns. The prognosis depends on etiology, response to therapy if treatable, and the gestational age at detection and delivery. Aneuploidy confers a poor prognosis, and even in the absence of aneuploidy, neonatal survival is often <50%. Mirror syndrome is a form of severe preeclampsia that may develop in association with fetal hydrops and in most cases necessitates delivery.

Successful medical treatment of fetal supraventricular tachycardia that cause hydrops fetalis

Supraventricular tachycardia (SVT) is the most frequent fetal tachyarrhythmia. Diagnosis is established with M-mode ultrasound and/or Doppler investigation. Untreated cases may develop fetal heart failure and hydrops. Even these cases should not be left untreated - maternal administration of anti-arrhythmic drugs should be undertaken. In this manuscript, we describe a successful treatment with maternal administration of sotalol and digoxin in a fetus that developed hydrops because of SVT.

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.