Arrhythmias in the Fetus.

Diagnosis and management of fetal arrhythmias have changed over the past 40-50 years since propranolol was first used to treat fetal tachycardia in 1975 and when first attempts were made at in utero pacing for complete heart block in 1986. Ongoing clinical trials, including the FAST therapy trial for fetal tachycardia and the STOP-BLOQ trial for anti-Ro-mediated fetal heart block, are working to improve diagnosis and management of fetal arrhythmias for both mother and fetus. We are also learning more about how "silent arrhythmias", like long QT syndrome and other inherited channelopathies, may be identified by recognizing "subtle" abnormalities in fetal heart rate, and while echocardiography yet remains the primary tool for diagnosing fetal arrhythmias, research efforts continue to advance the clinical envelope for fetal electrocardiography and fetal magnetocardiography. Pharmacologic management of fetal arrhythmias remains one of the most successful achievements of fetal intervention. Patience, vigilance, and multidisciplinary collaboration are key to successful diagnosis and treatment.

Fetal arrhythmias frequently co-occur with congenital heart disease in fetuses. The peaks observed in M-mode fetal echocardiograms serve as pivotal diagnostic markers for fetal arrhythmias. However, speckles, artifacts, and noise pose notable challenges for accurate image analysis. While current deep learning networks mainly overlook cardiac cyclic information, this study concentrated on the integration of such features, leveraging contextual constraints derived from cardiac cyclical features to improve diagnostic accuracy. This study proposed a novel deep learning architecture for diagnosing fetal arrhythmias. The architecture presented a loss function tailored to the cardiac cyclical information and formulated a diagnostic algorithm for classifying fetal arrhythmias. The training and validation processes utilized a dataset comprising 4440 patches gathered from 890 participants. Incorporating cyclic loss significantly enhanced the performance of deep learning networks in predicting peak points for diagnosing fetal arrhythmia, resulting in improvements ranging from 7.11% to 14.81% in F1-score across different network combinations. Particularly noteworthy was the 18.2% improvement in the F1-score for the low-quality group. Additionally, the precision of diagnosing fetal arrhythmia across four categories exhibited improvement, with an average improvement rate of 20.6%. This study introduced a cyclic loss mechanism based on the cardiac cycle information. Comparative evaluations were conducted using baseline methods and state-of-the-art deep learning architectures with the fetal echocardiogram dataset. These evaluations demonstrated the proposed framework's superior accuracy in diagnosing fetal arrhythmias. It is also crucial to note that further external testing is essential to assess the model's generalizability and clinical value.

Sustained fetal arrhythmia can produce life-threatening fetal distress, fetal hemodynamic compromise, hydrops fetalis, or even fetal death. Survivors may subsequently possess severe neurologic deficits. We conducted a retrospective observational study of pregnant women hospitalized with fetal arrhythmias from January 2011 to May 2020 at West China Second University Hospital, and fetal arrhythmias were diagnosed by specialists in cardiac ultrasonography. Of 90 cases of fetal arrhythmias, 14 (15.6%) were complicated by fetal congenital heart disease (CHD), 21 (23.33%) by fetal-hydrops, 15 (16.67%) cases by intrauterine therapy, and 6 (6.67%) by maternal auto-immune disease. In the fetal-hydrops group, the intrauterine therapy rate was significantly higher (47.62% vs 7.24%, P < .001) and the survival rate significantly lower (47.62% vs 92.75%, P < .001) than in the nonfetal hydrops group. A fetus whose arrhythmia was complicated by fetal-hydrops and CHD was delivered earlier and exhibited a lower cardiovascular profile score at diagnosis and birth, lower birth weight, and a higher rate of pregnancy termination than cases without hydrops and CHD (P < .05). Among the cases with maternal auto-immune disease, 71.43% (5/7) manifested fetal atrioventricular block. Multiple linear regression analysis revealed that 3 variables - fetal-hydrops (P < .001), body mass index (P = .014), and gestational age at diagnosis of fetal arrhythmia (P = .047) - were correlated with the gestational delivery age of arrhythmic fetuses. Parents should be counseled by the multidisciplinary team regarding the individualized management and prognosis of the arrhythmic fetus, and individualized fetal intrauterine therapy should be performed if necessary.

Key content Fetal cardiac arrhythmias are relatively common and account for up to 20% of referrals to fetal cardiologists. Arrhythmias may occur because of structural abnormalities of the fetal heart, or because of abnormal functioning of the cardiac conduction system in an otherwise structurally normal heart. Arrhythmias may be diagnosed using ultrasound and M‐mode and Doppler echocardiography. Transplacental therapy for tachyarrhythmias has been one of the success stories of fetal cardiology, and good outcomes can be expected in the absence of hydrops. Congenital heart block is most commonly caused by the transplacental passage of anti‐Ro and anti‐La antibodies and transplacental therapy is less successful in managing this. Learning objectives To enable clinicians to provide better counselling for patients about the prognosis of fetal arrhythmias. To learn how to diagnose fetal arrhythmias and know when to refer to a specialist centre if the diagnosis is suspected. To understand the treatment options available and the evidence‐based antenatal care schedule.

Objective:Fetal arrhythmias complicate 1-2% of all pregnancies. Ultrasound evaluation and Doppler technology are indispensable in both diagnosis and management. Digoxin, sotalol, flecainide and amiodarone are widely accepted antiarrhythmic agents that are frequently. We reviewed the maternal and fetal outcomes in cases with fetal arrhythmia in a tertiary care center in the last decade.Materials and Methods:Fetal arrhythmias were classified under three main groups: Irregular rhythms, tachyarrhythmia and bradyarrhythmia. Detailed anatomical evaluation and fetal echocardiography were performed in all cases to determine whether a structural cardiac and extracardiac anomaly accompanied fetal arrhythmia and the type of fetal arrhythmia. Digoxin was started primarily as first-line therapy in patients with persistent fetal tachyarrhythmia. In cases, not responding to digoxin, other antiarrhythmic agents (sotalol, flecainide) were combined with treatment without discontinuing digoxin.Results:Fetal arrhythmia was detected in 36 cases during the study period. 50% (n=18/36) of the cases had supraventricular tachycardia, whereas 28% (n=10/36) of them were fetal bradyarrhythmia and 22% (n=8/36) of them were with various irregular rhythms. Transplacental therapy was initiated in 13 patients with persistent supraventricular tachycardia and atrial flutter regardless of the presence of hydrops. The success rate in transplacental therapy was 77% (n=10/13).Conclusion:Successful transplacental therapy was achieved in approximately 80% of cases and delivery could be postponed to advanced gestational weeks, confirming the crucial role of this treatment for the management of tachyarrhythmia.

Timely prenatal diagnosis of various pathological conditions of the fetal heart is a particularly important problem of obstetric practice. For this purpose, the most frequently used are innovative ultrasound diagnostic technologies that give the opportunity to timely detect various fetal arrhythmias. Clinically significant arrhythmias are established to develop in fetuses and newborns in 1 out of 4,000 live births and are one of the causes of morbidity and mortality. About 10% of fetal arrhythmias require intrauterine treatment or constant monitoring, and they may also indicate the presence of serious hereditary syndromes associated with cardiac rhythm disorders and the likelihood of sudden infant death. The purpose of the review is to study the material of literature sources devoted to the primary prenatal ultrasound diagnosis of clinically significant fetal arrhythmias and dynamic echographic control in the management of pregnant women with fetal tachyarrhythmia. During the research, available domestic and foreign sources were used, which presented the features of the course of fetal cardiac arrhythmias, their types, and the possibilities of prenatal ultrasound diagnosis of this pathology. The search for publications is performed in databases eLIBRARY.RU , RSCI, PubMed, Embase. Based on the results of the analysis and generalization of the studied publications, it was found that ultrasound examination of the fetal heart plays a key role in the diagnosis of arrhythmias, it helps to determine the main mechanism of rhythm disturbance, assess the effect of arrhythmia on the fetal heart's functioning, exclude possible structural changes in the fetal heart, as well as enables to monitor the fetal condition during antiarrhythmic therapy. If fetal arrhythmias are suspected, an urgent ultrasound examination with ultrasound Dopplerography is recommended with an extension of the standard protocol for examining the fetal heart with an assessment of the frequency of atrial and ventricular contractions.

Ever since the first report on fetal magnetocardiography by Kariniemi in 1974 numerous studies have examined cardiac activity in healthy fetuses using this technique. Recently there has been an increase in reports on the identification of fetal pathological states, in particular in the diagnosis of fetal arrhythmias, using magnetocardiography. Other possible applications of this non-invasive method include the assessment of intrauterine growth retardation and fetal stress. In a patient with gestational hypertension and asymmetric growth retardation without pathological ultrasound findings, fetal magnetocardiography showed a reduced beat-to-beat heart rate variability indicating signs of fetal stress. On the day following the magnetocardiographic recording, fetal Doppler ultrasonography findings indicated an incipient brain sparing effect. The fetal growth retardation was reflected in the duration of the fetal cardiac time intervals. We conclude that fetal magnetocardiography non-invasively enables the timely identification of pathological fetal conditions.

Echocardiography is widely used for the diagnosis of fetal cardiac arrhythmias. However, this method does not detect configurational changes in the electrocardiogram (ECG) such as life-threatening changes in QRS and the prolongation of the QT interval. Fetal magnetocardiography (fMCG) and fetal electrocardiography (fECG) are valuable tools for the detection of electrophysiological cardiac signals although both have certain limitations. Such techniques must deal with excess internal noise such as maternal respiratory movements, fetal movements, muscle contraction and fetal body movement and external noise (e.g., electromagnetic waves). Heart rate variability (HRV) is a well-known phenomenon with fluctuation in the time interval between heartbeats. The lack of translation invariance is a serious defect in the conventional wavelet transforms (discrete wavelet transform (DWT)). Fluctuation of the impulse response at each energy level is observed in the multi-resolution analysis (MRA). Configurational changes in the ECG waveforms are frequently observed after noise reduction by the conventional wavelet transforms. Both the lack of translation invariance of conventional wavelet transforms and HRV cause deformation of the ECG waveforms. We describe here the CDWTs with perfect translation invariance (PTI). Compared with conventional wavelets, PTI of the fECG and fMCG resulted in only minor configurational changes in the ECG waveforms. This technique yields persistently stable ECG waveforms, including P wave and QRS complex. First, an independent component analysis (ICA) was applied to fECG or fMCG data to remove noise. We provide an example to show that the morphological change in QRS complex is barely affected when PTI is applied to normal fECG. Examples of fetal arrhythmias, such as ventricular trigeminy, ventricular bigeminy and premature atrial contraction are demonstrated using this technique. The results lead us to the conclusion that ICA and noise reduction in fECG and fMCG by PTI are promising methods for the diagnosis of fetal arrhythmia.

Fetal arrhythmias present as an irregular cardiac rhythm and heart rate. Fetal echocardiography and cardiotocography play a pivotal role in diagnosing and managing fetal arrhythmia. Fetal magnetocardiography and electrocardiography can provide electrical assessment but have several limitations; thus, prenatal diagnosis of fetal arrhythmia remains challenging. Most cases of fetal arrhythmia have a structurally normal heart with isolated premature contractions that spontaneously resolve in utero or after birth without treatment. Despite the theoretical advantage of fetoplacental circulation, progression to heart failure or hydrops is found in fetuses with tachy- or bradyarrhythmia due to the limited heart rate reserve. There is a clear clinical consensus on the efficacy of transplacental antiarrhythmic therapy using digoxin, sotalol, and flecainide for fetal supraventricular tachyarrhythmia. A recent Japanese multicenter clinical trial confirmed the efficacy and safety of these agents. Fetal ventricular tachycardia is an infrequent occurrence but can be associated with heart failure, hydrops, and sudden death. It is important to search for long QT syndrome. Transplacental administration of magnesium, propranolol, mexiletine, and lidocaine, alone or in combination, has been attempted for fetal ventricular tachycardia. Fetal complete atrioventricular block is caused by maternal autoantibodies or fetal congenital heart defects and is irreversible. There is currently no consensus on the indications for fetal treatment, including beta-sympathomimetics for bradyarrhythmia. Dexamethasone and intravenous immunoglobulin have been used to prevent or treat atrioventricular block and myocarditis, but recent studies have not shown the efficacy of these agents.

Fetal arrhythmias (FA) are reported in the literature in 1% to 5% of all pregnancies, and about 10% of cases are potentially harmful to fetal life. It should be emphasised that both the diagnosis and treatment of FA are still relevant, unresolved and controversial.The objective: to determine the diagnostic and prognostic value and the relationship of the main morphometric parameters and abnormal macroscopic findings of the umbilical cord and placenta with the development of heart failure in the case of FA.Material and methods. 102 pregnant women were included in the study. The main group involved 72 pregnant women with fetal heart rhythm disturbances – FA, the control group – 30 somatically healthy patients with a physiological course of pregnancy and satisfactory intrauterine fetal condition. During the study, 4 cases of antenatal fetal death were excluded from the main group. Ultrasound examination of the fetal cardiac structure and recording of fetal cardiac activity were carried out. Postnatal macroscopic examination of the placenta and umbilical cord were studied: placental weight, its shape, thickness, presence of macroscopic involutional-dystrophic changes, umbilical cord length and diameter, number of vessels, tortuosity index, type of the placenta insertion, volume of Wharton’s jelly, presence of knots and entanglement of the umbilical cord.Results. Pregnancy in the group with FA was accompanied by a high percentage of complications (86.8%), in which the most important factors in terms of stratification of the risk of negative perinatal outcomes were the threat of pregnancy loss (26.5%), acute respiratory infections in the first half of pregnancy (30.9%), asymptomatic bacteriuria and vaginitis, autoimmune disorders (antiphospholipid syndrome, autoimmune thyroiditis), latent cytomegalovirus infection (27.9%), and gestational diabetes (22.1%). Pregnancies with FA were associated with an increased proportion of preterm births (20.6%), birth of a fetal low weight for a gestational age (29.4%), surgical delivery (32.4%), antenatal death (4.4%) and the need for intensive care (13.2%).Out of 68 live births, 55 children (88.9%) were born with an Apgar score of ≥ 7 points, 13 babies (19.1%) were born with an Apgar score of ≤ 6 points, 9 babies (13.2%) were transferred to the neonatal intensive care unit, and birth weight &lt; 10th percentile was found in 20 cases (29.4%).The postnatal macroscopic examination of the placenta and umbilical cord demonstrated an increased rate of macroscopic umbilical cord abnormalities (37.5%), namely eccentric umbilical cord insertion (61.8%), marginal and velamentous umbilical cord insertion (22.1%), an increased frequency of short umbilical cord (47.1%), changes in the umbilical cord tortuosity index (hyper-tortuosity (42.6%) and hypotortuosity (33.8%)), and deficiency of Wharton’s jelly (27.9%). The assessment of the identified features of postnatal placental macromorphology revealed an increase in placental tissue weight, a decrease in average thickness and an increased rate of abnormal forms (60.3%).Conclusions. Macroscopic abnormalities of the placenta and umbilical cord were diagnosed postnatally in patients with FA, namely an increase in the weight of the placental tissue, a decrease in the average thickness and an increased rate of abnormal forms (60.3%), eccentric insertion of the umbilical cord (61.8%), marginal and velamentous umbilical cord insertion (22.1%), increase in the proportion of short umbilical cord (47.1%), changes in the umbilical cord tortuosity index (hyper-tortuosity up to 42.6% and hypotortuosity up to 33.8%), and deficiency of Wharton’s jelly (27.9%).

Simultaneous recordings of pulsed wave Doppler signals in hepatic vein and descending aorta using dual Doppler: a novel method for evaluating fetal arrhythmias

Objectives: Fetal cardiac rhabdomyomas are rare but well-known to be associated with arrhythmia or conduction abnormalities. However, since in utero electrophysiological information is quite limited, it remains unclear which type of rhabdomyoma will develop arrhythmia after birth. The aim of this study is to identify factors that predict postnatal arrhythmia requiring therapy in fetuses with cardiac rhabdomyoma.Study design: A retrospective review of infants prenatally diagnosed with cardiac rhabdomyoma was performed at our tertiary pediatric cardiac center between 1990 and 2016. Fetal arrhythmia was diagnosed using fetal echocardiography and magnetocardiography. We compared the characteristics of cases with and without antiarrhythmic therapy after birth. Cases without antiarrhythmic therapy after birth consisted of those who had postnatal arrhythmia but did not require antiarrhythmic therapy and those who had no postnatal arrhythmia.Results: A total of 20 fetuses with cardiac rhabdomyoma were included in this study. Ten cases (50%) were confirmed as having tuberous sclerosis after birth. The mean gestational week at diagnosis and delivery were 32.1 ± 2.7 and 37.6 ± 2.8 weeks, respectively. Mean cardiac tumor size in utero was 21 ± 11 mm (range, 7–54 mm) in diameter. Fetal arrhythmia was found in six cases; three resolved in utero with transplacental antiarrhythmic therapy. Postnatal arrhythmia or conduction abnormalities were found in 12 cases; 7 required antiarrhythmic therapy. Cases with antiarrhythmic therapy after birth had larger cardiac tumor in utero than those without therapy (29.6 ± 12.8 mm versus 16.3 ± 5.8 mm, p < .01). Cardiac tumor size >30 mm in diameter predicted postnatal arrhythmia requiring therapy with sensitivity of 57.1% and specificity of 100%. Location and number of cardiac tumor and presence of arrhythmia or conduction abnormalities in utero were similar between the two groups.Conclusions: Cardiac rhabdomyomas >30 mm in diameter are associated with postnatal arrhythmia requiring therapy regardless of number and location.

Objective To evaluate the diagnostic value of tissue Doppler imaging (TDI) in classification of fetal arrhythmias, and conclude characters of each type of arrhythmias by analyzing wave forms of TDI. Methods Fifty-five fetuses suffered arrhythmia were included in study group. By comparing the results with control standard(M and PW), the sensitivity, specificity and reliability of TDI in diagnosis of fetal arrhythmias was calculated. At last, the character of waves by TDI of each type of arrhythmia was concluded. Fetal kinetocardiogram was made to identify the origin of arrhythmias. All cases were asked to perform electrocardiography and echocardiography examination after birth. Results The sensitivity, specificity and reliability of TDI was 98%, 100% and 100%, respectively. The character of atrioventricular waves and kinetocardiogram of 8 types fetal arrhythmias were conclude. Conclusions TDI has great value in classification of fetal arrhythmias. Key words: Ultrasonography,prenatal; Fetal heart; Arrhythmia

Objective To evaluate the value of fetal dual Doppler ultrasonography in the diagnosis of fetal arrhythmias. Methods 77 531 fetuses were examined by echocardiography.If fetal arrhythmias were found, information of pulsed wave Doppler signals in hepatic vein (HV) and descending aorta (DAo) using dual Doppler were collected simultaneously. Results On dual Doppler examination, 131 of the fetuses showed signals of cardiac dysrhythmias, including 60 fetuses with irregular fetal heart rhythm but having normal heart rate, 45 with tachyarrhythmias and 26 with bradyarrhythmias. Sixteen and 2 with tachy- or bradyarrhythmias fetuses complicated fetal malformation or severely maternal systemic diseases. Eighteen and 3 with tachy- or bradyarrhythmias fetuses revealed intrauterine death or intermediate pregnancy induction. The three main kinds of fetal arrhythmias had statistical differences in complicating with fetal malformation, maternal diseases, intrauterine fetal demise or intermediate pregnancy induction(all P<0.05). There was a significant difference in the accuracy of diagnosing rhythm abnormalities in the fetus between conventional ultrasonography and dual Doppler ultrasonography(k=0.562, P<0.05). Sixty cases of irregular fetal heart rhythm, 42 cases of fetal tachyarrhythmias, and 8 cases of fetal bradyarrhythmias were changed to normal rhythm at the third-pregnancy or prenatal period through appropriate treatment. All surviving fetuses were examined by echocardiography within 3 days, without any combination of congenital heart disease, and 1 months after the delivery, the ECG were shown as sinus rhythm. Conclusions Dual Doppler ultrasonography is a precise and rapid method of assessing various types of fetal arrhythmias. Different types of fetal arrhythmias have different fetal prognosis. Key words: Echocardiography, Doppler; Fetal heart; Arrhythmias; Dual Doppler

P92. When there is a lack of magnesium during pregnancy