Fetal arrhythmia: Prenatal diagnosis and perinatal management

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.

Double Doppler Tei index combined with lung ultrasound to evaluate the right ventricular function and lung condition in neonates with pulmonary hypertension

PURPOSE

To explore the applicability of the Tei index combined with lung ultrasound score (LUS) in the evaluation of the lung condition and the right ventricular function of patients with neonatal pulmonary hypertension (PH).

METHODS

Thirty healthy neonates and 75 neonates with PH were included. Two-dimensional, M-mode, and double Doppler ultrasound were used to detect RVFAC, TAPSE, TAPSV, and double Doppler Tei index (DD-Tei index). Intra-group correlation coefficient (ICC), Bland-Altman, the Spearman rank method, and the ROC (receiver operating characteristic) were used for other objectives within the study. LUS was used to score the lung condition of 75 neonates with PH with or without respiratory distress and 30 normal neonates in the control group, and the differences were compared. Spearman rank correlation was used to analyze the lung score, DD-Tei index, pulmonary artery pressure, assisted breathing therapy, and the correlation of invasive mechanical ventilation.

RESULTS

There were statistically significant differences in the decrease of the values of RVFAC, TAPSE, TAPSV, and the increase of the DD-Tei index among the groups. RVFAC, TAPSE, TAPSV, and DD-Tei index showed good performance for PH, and the DD-Tei index had the best diagnostic performance. The increase in pulmonary artery pressure, lung score, and DD-Tei index in the PH were statistically significant compared with the control group. The DD-Tei index and lung scores were positively correlated with pulmonary artery pressure, assisted breathing therapy, and invasive mechanical ventilation.

CONCLUSION

Dual Doppler ultrasonography combined with pulmonary ultrasound performed well in the assessment of the right ventricular function and lung condition of neonatal with PH.

Abnormal fetal heart rate patterns caused by pathophysiologic processes other than fetal acidemia

Fetal acidemia is a common final pathway to fetal death, and in many cases, to fetal central nervous system injury. However, certain fetal pathophysiological processes are associated with significant category II or category III fetal heart rate changes before the development of or in the absence of fetal acidemia. The most frequent of these processes include fetal infection and/or inflammation, anemia, fetal congenital heart disease, and fetal central nervous system injury. In the presence of significant category II or category III fetal heart rate patterns, clinicians should consider the possibility of the aforementioned fetal processes depending on the clinical circumstances. The common characteristic of these pathophysiological processes is that their associated fetal heart rate patterns are linked to increased adverse neonatal outcomes despite the absence of acidemia at birth. Therefore, in these cases, the fetal heart rate patterns may provide more insight about the fetal condition and pathophysiology than the acid-base status at birth. In addition, as successful timing of intrapartum interventions on the basis of evolution of fetal heart rate patterns aims to prevent fetal acidemia, it may not be logical to continue to use the fetal acid-base status at birth as the gold standard outcome to determine the predictive ability of category II or III fetal heart rate patterns. A more reasonable approach may be to use the umbilical cord blood acid-base status at birth as the gold standard for determining the appropriateness of the timing of our interventions.

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.

Transplacental Therapeutic Drug Monitoring in Pregnant Women with Fetal Tachyarrhythmia Using HPLC-MS/MS

Fetal arrhythmia develops in 0.1-5% of pregnancies and may cause fetal heart failure and fetal hydrops, thus increasing fetal, neonatal, and infant mortality. The timely initiation of transplacental antiarrhythmic therapy (ART) promotes the conversion of fetal tachycardia to sinus rhythm and the regression of the concomitant non-immune fetal hydrops. The optimal treatment regimen search for the fetus with tachyarrhythmia is still of high value. Polymorphisms of these genes determines the individual features of the drug pharmacokinetics. The aim of this study was to study the pharmacokinetics of transplacental anti-arrhythmic drugs in the fetal therapy of arrhythmias using HPLC-MS/MS, as well as to assess the effect of the multidrug-resistance gene ABCB1 3435C > T polymorphism on the efficacy and maternal/fetal complications of digoxin treatment. The predisposition to a decrease in the bioavailability of the digoxin in patients with a homozygous variant of the CC polymorphism showed a probable association with the development of ART side effects. A pronounced decrease in heart rate in women with the 3435TT allele of the ABCB1 gene was found. The homozygous TT variant in the fetus showed a probable association with an earlier response to ART and rhythm disruptions on the digoxin dosage reduction. high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) methods for digoxin and sotalol therapeutic drug monitoring in blood plasma, amniotic fluid, and urine were developed. The digoxin and sotalol concentrations were determined in the plasma blood, urine, and amniotic fluid of 30 pregnant women at four time points (from the beginning of the transplacental antiarrhythmic therapy to delivery) and the plasma cord blood of 30 newborns. A high degree of correlation between the level of digoxin and sotalol in maternal and cord blood was found. The ratio of digoxin and sotalol in cord blood to maternal blood was 0.35 (0.27 and 0.46) and 1.0 (0.97 and 1.07), accordingly. The digoxin concentration in the blood of the fetus at the moment of the first rhythm recovery episode, 0.58 (0.46, 0.8) ng/mL, was below the therapeutic interval. This confirms the almost complete transplacental transfer of sotalol and the significant limitation in the case of digoxin. Previously, ABCB1/P-glycoprotein had been shown to limit fetal exposure to drugs. Further studies (including multicenter ones) to clarify the genetic features of the transplacental pharmacokinetics of antiarrhythmic drugs are needed.

Fetal Arrhythmia Diagnosis and Pharmacologic Management

One of the most successful achievements of fetal intervention is the pharmacologic management of fetal arrhythmias. This management usually takes place during the second or third trimester. While most arrhythmias in the fetus are benign, both tachy‐ and bradyarrhythmias can lead to fetal hydrops or cardiac dysfunction and require treatment under certain conditions. This review will highlight precise diagnosis by fetal echocardiography and magnetocardiography, the 2 primary means of diagnosing fetuses with arrhythmia. Additionally, transient or hidden arrhythmias such as bundle branch block, QT prolongation, and torsades de pointes, which can lead to cardiomyopathy and sudden unexplained death in the fetus, may also need pharmacologic treatment. The review will address the types of drug therapies; current knowledge of drug usage, efficacy, and precautions; and the transition to neonatal treatments when indicated. Finally, we will highlight new assessments, including the role of the nurse in the care of fetal arrhythmias. The prognosis for the human fetus with arrhythmias continues to improve as we expand our ability to provide intensive care unit–like monitoring, to better understand drug treatments, to optimize subsequent pregnancy monitoring, to effectively predict timing for delivery, and to follow up these conditions into the neonatal period and into childhood. Coordinated initiatives that facilitate clinical fetal research are needed to address gaps in knowledge and to facilitate fetal drug and device development.

In-vivo Sino-Atrial Node Mapping in Children and Adults With Congenital Heart Disease

BACKGROUND

Sinus node dysfunction (SND) and atrial tachyarrhythmias frequently co-exist in the aging patient with congenital heart disease (CHD), even after surgical correction early in life. We examined differences in electrophysiological properties of the sino-atrial node (SAN) area between pediatric and adult patients with CHD.

METHODS

Epicardial mapping of the SAN was performed during sinus rhythm in 12 pediatric (0.6 [0.4-2.4] years) and 15 adult (47 [40-55] years) patients. Unipolar potentials were classified as single-, short or long double- and fractionated potentials. Unipolar voltage, relative R-to-S-amplitude ratio and duration of all potentials was calculated. Conduction velocity (CV) and the amount of conduction block (CB) was calculated.

RESULTS

SAN activity in pediatric patients was solely observed near the junction of the superior caval vein and the right atrium, while in adults SAN activity was observed even up to the middle part of the right atrium. Compared to pediatric patients, the SAN region of adults was characterized by lower CV, lower voltages, more CB and a higher degree of fractionation. At the earliest site of activation, single potentials from pediatrics consisted of broad monophasic S-waves with high amplitudes, while adults had smaller rS-potentials with longer duration which were more often fractionated.

CONCLUSIONS

Compared to pediatric patients, adults with uncorrected CHD have more inhomogeneous conduction and variations in preferential SAN exit site, which are presumable caused by aging related remodeling. Long-term follow-up of these patients is essential to demonstrate whether these changes are related to development of SND and also atrial tachyarrhythmias early in life.

Management of Fetal Supraventricular Tachycardia: Case Series from a Tertiary Perinatal Cardiac Center

BACKGROUND

Fetal supraventricular tachycardia is a relatively uncommon cardiac rhythm abnormality which is often associated with adverse perinatal outcomes if untreated. Although there are several treatment modalities and protocols in use globally, there is no consensus as to the most effective antiarrhythmic to manage this condition.

AIM

This study aimed to evaluate perinatal outcomes following prenatal maternal therapy for fetal supraventricular tachycardia.

MATERIALS AND METHODS

This was a 20-year retrospective cohort study. Institutional records were reviewed for antenatal therapy choice and maternal and fetal outcomes.

RESULTS

Sixty-nine cases met diagnostic criteria for fetal SVT, of which 56 (81%) received maternal antiarrhythmic therapy. Digoxin was the most common, but least effective, first-line therapy in 28 patients, achieving successful rate reversion in 35.7%. Thirty-one patients (55%) required second-line therapy, and this was most successful with digoxin and flecainide polytherapy achieving rate reversion in 17 of 18 cases (94.5%) at a median of 3 days (1.5-7). Hydrops was present in 23 (33%) cases at initial presentation, 16 of which achieved rate reversion. There was minimal difference in treatment efficacy comparing single- or multiple-agent treatment in the setting of hydrops (50% vs. 42.8%). Side effects occurred in 14/56 treated patients (25%) but were severe in only 8 (14.3%) women, most commonly with digoxin and flecainide polytherapy (6 of 8 cases). There were 3 (4%) fetal deaths amongst the study cohort.

CONCLUSIONS

Digoxin and flecainide polytherapy were well tolerated and successfully achieved rhythm and rate control in fetuses with prenatally diagnosed supraventricular tachycardia. The presence of hydrops was a poor prognostic feature.

Clinical and genetic spectrum of neonatal arrhythmia in a NICU

BACKGROUND

Neonatal arrhythmia is a common complication that might be life-threatening or serious, but the genetic causes are unclear in most cases. The aim of this study is to investigate the genetic causes of neonatal arrhythmia in a NICU in China.

METHODS

Newborns who were diagnosed with arrhythmia during the neonatal period were enrolled from Children's Hospital of Fudan University between January 1st 2016, and December 31st, 2019. A neonatal gene panel was performed for each infant.

RESULTS

In total, 98 neonatal infants with arrhythmia were enrolled. Fourteen genes and a copy number change were identified and classified as pathogenic/likely pathogenic in 22 patients (22.4%), including 4 genes related to syndrome, 4 related to conduction, 2 related to metabolism, 2 related to structure, 2 related to respiration and immunity, respectively, and trisomy 21. Altogether, 6 genes (6/14, 42.9%) caused original heart structure or conduction abnormalities, leading to arrhythmia. Infants with ventricular tachycardia or fibrillation, atrioventricular block and long-QT syndrome all had positive gene results. The gene positive rate among arrhythmic infants with congenital heart disease or severe heart failure was higher than that of infants without congenital heart disease or severe heart failure.

CONCLUSIONS

The genetic disorders associated with neonatal arrhythmia could be syndrome-, conduction-, metabolism-, and structure-related. Infants with non-benign arrhythmia, especially ventricular tachycardia or fibrillation, long-QT syndrome, or high-grade atrioventricular block, have a higher rate of genetic abnormalities and should undergo genetic sequencing. Neonates with hereditary arrhythmias may have a higher risk of congenital heart disease or heart failure.

Treatment of Fetal Arrhythmias

Fetal arrhythmias are mostly benign and transient. However, some of them are associated with structural defects or can cause heart failure, fetal hydrops, and can lead to intrauterine death. The analysis of fetal heart rhythm is based on ultrasound (M-mode and Doppler echocardiography). Irregular rhythm due to atrial ectopic beats is the most common type of fetal arrhythmia and is generally benign. Tachyarrhythmias are diagnosed when the fetal heart rate is persistently above 180 beats per minute (bpm). The most common fetal tachyarrhythmias are paroxysmal supraventricular tachycardia and atrial flutter. Most fetal tachycardias can be terminated or controlled by transplacental or direct administration of anti-arrhythmic drugs. Fetal bradycardia is diagnosed when the fetal heart rate is slower than 110 bpm. Persistent bradycardia outside labor or in the absence of placental pathology is mostly due to atrioventricular (AV) block. Approximately half of fetal heart blocks are in cases with structural heart defects, and AV block in cases with structurally normal heart is often caused by maternal anti-Ro/SSA antibodies. The efficacy of prenatal treatment for fetal AV block is limited. Our review aims to provide a practical guide for the diagnosis and management of common fetal arrythmias, from the joint perspective of the fetal medicine specialist and the cardiologist.

Successful management of fetal atrial flutter at term pregnancy with postnatal electrocardioversion

Fetal atrial flutter is a lethal tachyarrhythmia with a 10% mortality rate. Diagnosis is made with echocardiography, and management should be multidisciplinary with obstetricians, fetal cardiologists, and specialist neonatologists.

Paroxysmal Supraventricular Tachycardia in Wolff–Parkinson–White Syndrome in a Newborn—Case Report and Mini-Review

Wolff–Parkinson–White (WPW) syndrome is a rare abnormal condition frequently associated with paroxysmal supraventricular tachycardia (PSVT) and is described as an arrhythmia under the form of increased heartbeat. Currently, there are various possible treatments going from medicines such as adenosine and beta-blockers to cardioversion. The unknown causes of this condition together with the different responses to treatment in each patient make it difficult to establish the best therapeutic approach. In this context, in the current paper, we were interested in reporting the therapeutic options and their efficiency in the case of associated heart or inflammatory conditions in a 13-day-old patient.

Current perspective and scope of fetal therapy: part 1

Fetal therapy term has been described for any therapeutic intervention either invasive or noninvasive for the purpose of correcting or treating any fetal malformation or condition. Fetal therapy is a rapidly evolving specialty and has gained pace in last two decades and now fetal intervention is being tried in many malformations with rate of success varying with the type of different fetal conditions. The advances in imaging techniques have allowed fetal medicine persons to make earlier and accurate diagnosis of numerous fetal anomalies. Still many fetal anomalies are managed postnatally because the fetal outcomes have not changed significantly with the use of fetal therapy and this approach avoids unnecessary maternal risk secondary to inutero intervention. The short-term maternal risk associated with fetal surgery includes preterm labor, premature rupture of membranes, uterine wall bleeding, chorioamniotic separation, placental abruption, chorioamnionitis, and anesthesia risk. Whereas, maternal long-term complications include risk of infertility, uterine rupture, and need for cesarean section in future pregnancies. The decision for invasive fetal therapy should be taken after discussion with parents about the various aspects like postnatal fetal outcome without fetal intervention, possible outcome if the fetal intervention is done, available postnatal intervention for the fetal condition, and possible short-term and long-term maternal complications. The center where fetal intervention is done should have facility of multi-disciplinary team to manage both maternal and fetal complications. The major issues in the development of fetal surgery include selection of patient for intervention, crafting effective fetal surgical skills, requirement of regular fetal and uterine monitoring, effective tocolysis, and minimizing fetal and maternal fetal risks. This review will cover the surgical or invasive aspect of fetal therapy with available evidence and will highlight the progress made in the management of fetal malformations in last two decades.

Resolution of Fetal Hydrops Dependent on Sustained Fetal Supraventricular Tachycardia after Digoxin Therapy

We present a special case of fetal supraventricular tachycardia detected at 34 weeks gestation. Fetal hydrops was noted on ultrasound upon admission. Normal fetal heart rate was maintained for three weeks by maternal administration of digoxin. A live infant was delivered via caesarian section at 37 weeks gestation. This clinical case demonstrated that pharmacological treatment can be effective and helps to prolong pregnancy safely.

Fetal arrhythmias: prenatal evaluation and intrauterine therapeutics

Introduction

Fetal arrhythmias are a common phenomenon with rather complicated etiologies. Debates remain regarding prenatal diagnosis and treatment of fetal arrhythmias.

Methods

The literature reporting on prenatal diagnosis and treatment of fetal arrhythmias published in the recent two decades were retrieved, collected and analyzed.

Results

Both fetal magnetocardiogram and electrocardiogram provide information of cardiac time intervals, including the QRS and QT durations. M-mode ultrasound detects the AV and VA intervals, fetal heart rate, and AV conduction. By using Doppler ultrasound, simultaneous recording of the atrial and ventricular waves can be obtained. Benign fetal arrhythmias, including premature contractions and sinus tachycardia, do not need any treatment before and after birth. Sustained fetal arrhythmias that predispose to the occurrence of hydrops fetalis, cardiac dysfunction or eventual fetal demise require active treatments. Intrauterine therapy of fetal tachyarrhythmias has been carried out by the transplacental route. If maternal transplacental treatment fails, intraumbilical, intraperitoneal, or direct fetal intramuscular injection of antiarrhythmic agents can be attempted.

Conclusions

The outcomes of intrauterine therapy of fetal tachyarrhythmias depend on the types or etiology of fetal arrhythmias and fetal conditions. Most are curable to a transplacental treatment by the first-line antiarrhythmic agents. Fetal cardiac pacings are effective methods to restore sinus rhythm in drug-resistant or hemodynamically compromised cases. Immediate postnatal pacemaker implantation is warranted in refractory cases.

Recovery of the fetal electrocardiogram for morphological analysis from two trans-abdominal channels via optimal shrinkage

OBJECTIVE

We propose a novel algorithm to recover fetal electrocardiogram (ECG) for both the fetal heart rate analysis and morphological analysis of its waveform from two or three trans-abdominal maternal ECG channels.

APPROACH

We design an algorithm based on the optimal-shrinkage under the wave-shape manifold model. For the fetal heart rate analysis, the algorithm is evaluated on publicly available database, 2013 PhyioNet/Computing in Cardiology Challenge, set A (CinC2013). For the morphological analysis, we analyze CinC2013 and another publicly available database, non-invasive fetal ECG arrhythmia database (nifeadb), and propose to simulate semi-real databases by mixing the MIT-BIH normal sinus rhythm database and MITDB arrhythmia database.

MAIN RESULTS

For the fetal R peak detection, the proposed algorithm outperforms all algorithms under comparison. For the morphological analysis, the algorithm provides an encouraging result in recovery of the fetal ECG waveform, including PR, QT and ST intervals, even when the fetus has arrhythmia, both in real and simulated databases.

SIGNIFICANCE

To the best of our knowledge, this is the first work focusing on recovering the fetal ECG for morphological analysis from two or three channels with an algorithm potentially applicable for continuous fetal electrocardiographic monitoring, which creates the potential for long term monitoring purpose.

Importance of stabilization of the neonatal transport network in critically ill neonates

Objective

This study aimed to investigate how to stabilize the condition of critically ill neonates within the neonatal transport network.

Methods

A total of 243 critically ill newborns in four hospitals involved in the transport network were enrolled. The newborns were divided into the research and control groups. In the research group, medical staff underwent theoretical training, and neonatal intensive care unit (NICU) professionals participated and provided on-site guidance on delivery of high-risk infants. Delivery of high-risk neonates in the control group was conventionally managed in local hospitals, and neonates were transferred after a phone call to the NICU.

Results

Gestational age and body weight were lower, and dexamethasone use was higher in the research group than in the control group. The proportions of neonates who underwent mask pressure, endotracheal intubation, pulmonary surfactant application, and chest compressions were higher, and those with dyspnea and nervous system abnormalities were lower in the research group than in the control group. Blood gas and sugar levels were better in the research group than in the control group.

Conclusion

Strengthening professional training and participation of professional NICU staff in childbirth can improve the conditions of high-risk neonates and increase safety of their transportation.

Fetal Heart Rate Auscultation, 3rd edition

The use of intermittent auscultation (IA) for fetal surveillance during labor decreased with the introduction of electronic fetal monitoring (EFM). The increased use of EFM is associated with an increase in cesarean births. IA is an evidence-based method of fetal surveillance during labor for women with low risk pregnancies and considered one component of comprehensive efforts to reduce the primary cesarean rate and promote vaginal birth. Many clinicians are not familiar with IA practice. This practice monograph includes information on IA techniques; interpretation and documentation; clinical decision-making and interventions; communication; education, staffing, legal issues, and strategies to promote implementation of IA into practice.

Fetal arrhythmias: Surveillance and management

Fetal arrhythmias warrant sophisticated surveillance and management, especially for the high-risk pregnancies. Clinically, fetal arrhythmias can be categorized into 3 types: premature contractions, tachyarrhythmias, and bradyarrhythmias. Fetal arrhythmias include electrocardiography, cardiotocography, echocardiography and magnetocardiography. Oxygen saturation monitoring can be an effective way of fetal surveillance for congenital complete AV block or SVT during labor. Genetic surveillance of fetal arrhythmias may facilitate the understanding of the mechanisms of the arrhythmias and provide theoretical basis for diagnosis and treatment. For fetal benign arrhythmias, usually no treatment but a close follow-up is need, while persistant fetal arrhythmias with congestive heart dysfunction or hydrops fetalis, intrauterine or postnatal treatments are required. The prognoses of fetal arrhythmias depend on the type and severity of fetal arrhythmias and the associated fetal conditions. Responses of fetal arrhythmias to individual treatments and clinical schemes are heterogeneous, and the prognoses are poor particularly under such circumstances.

Investigating fetal myocardial function in heart anomalies by Doppler myocardial performance indices

Fetal myocardial performance index are used to assess aspects of systolic and diastolic function in developing fetal heart. The aim of this study was to determine normal values of fetal left ventricular (LV) Tei Index (TI) for measuring systolic performance and K-Index (KI) for diastolic performance in early (<;32 weeks), Mid (32-35 weeks) and late trimester (35-41 weeks) normal fetuses and fetuses with congenital heart diseases (CHD). Simultaneous recordings of Doppler Ultrasound Signal (DUS) of the LV outflow tracts and fetal electrocardiogram signals were obtained in 57 normal and 14 fetuses with CHD. CHDs were categorized in two types (conduction pathway abnormalities [8 cases] and structural anomalies [6 cases]). The LV isovolumic contraction time (ICT), isovolumic relaxation time (IRT), ventricular ejection time (VET) and ventricular filling time (VFT) were measured from amplitudes and peaks of high frequency component of DUS signals by an automated model. The TI and the new index were calculated by using the formula (ICT + IRT)/VET and (ICT + IRT)/VFT respectively. The TI did not show any significant change from CHD (conduction) to CHD (structural) fetuses (0.72± 0.09 vs 0.76±0.02; NS). On the other hand, KI showed significant decline in values (0.82±0.24 vs 0.49±0.34; p<;0.05) during normal development period and CHD with structural anomalies particularly. The correlation of KI with gestational ages was found to be negative and significant (r=- 0.29; p=0.025). Both TI and KI can be easily obtained in the fetus from DUS recording without the need for precise anatomic imaging. In conclusion, KI may be a useful tool to explore the healthy development of fetal myocardial function and identify fetuses with CHD (structural). More research is needed to check if KI could recognize the compromised fetuses from normal ones in future.

Fetal cardiac arrhythmias: Current evidence

This article reviews important features for improving the diagnosis of fetal arrhythmias by ultrasound in prenatal cardiac screening and echocardiography. Transient fetal arrhythmias are more common than persistent fetal arrhythmias. However, persistent severe bradycardia and sustained tachycardia may cause fetal hydrops, preterm delivery, and higher perinatal morbidity and mortality. Hence, the diagnosis of these arrhythmias during the routine obstetric ultrasound, before the progression to hydrops, is crucial and represents a challenge that involves a team of specialists and subspecialists on fetal ultrasonography. The images in this review highlight normal cardiac rhythms as well as pathologic cases consistent with premature atrial and ventricular contractions, heart block, supraventricular tachycardia (VT), atrial flutter, and VT. In this review, the details of a variety of arrhythmias in fetuses were provided by M-mode and Doppler ultrasound/echocardiography with high-quality imaging, enhancing diagnostic accuracy. Moreover, an update on the intrauterine management and treatment of many arrhythmias is provided, focusing on improving outcomes to enable planned delivery and perinatal management.

M-mode Diagnosis of Tachyarrhythmia Can be Erroneous Owing to "Pseudo 1:1 Atrioventricular Movement" of the Atrial Wall Adjacent to the Atrioventricular Valve Possibly due to Atrioventricular Constraint: A Case of Neonatal Atrial Flutter With 2:1 Atrioventricular Conduction

M-mode echocardiography has been playing an important role in the diagnosis of fetal tachyarrhythmia. We recently encountered a neonatal case of atrial flutter with 2:1 atrioventricular conduction. However, M-mode erroneously indicated 1:1 atrioventricular movement. While the movement of the atrial wall far from the atrioventricular valve was much faster than that of the ventricular wall, the atrial wall adjacent to the atrioventricular valve fully synchronized to that of the ventricular wall. Thus, to avoid this novel pitfall, it would be important to add an additional assessment focusing on the movement of the atrial wall far from the ventricle.

Management of Supraventricular Tachycardia in Infants

Supraventricular tachycardia is the most common tachyarrhythmia encountered in infants. In older children and adults, definitive treatment of the supraventricular tachycardia substrate with catheter ablation is a common approach to management. However, in infants, the risks of catheter ablation are significantly higher, and the patients often outgrow the potential to experience episodes. Therefore, antiarrhythmic medications are often utilized to minimize the likelihood of experiencing episodes. This article reviews the common arrhythmia mechanisms encountered in infants and the medications used to treat these patients.

The use of non-invasive fetal electrocardiography in diagnosing second-degree fetal atrioventricular block

Background

Complete atrioventricular block in fetuses is known to be mostly associated with autoimmune disease and can be irreversible if no steroids treatment is provided. Conventional methods used in clinical practice for diagnosing fetal arrhythmia are limited since they do not reflect the primary electrophysiological conduction processes that take place in the myocardium. The non-invasive fetal electrocardiogram has the potential to better support fetal arrhythmias diagnosis through the continuous analysis of the beat to beat variation of the fetal heart rate and morphological analysis of the PQRST complex.

Case presentation

We present two retrospective case reports on which atrioventricular block diagnosis could have been supported by the non-invasive fetal electrocardiogram. The two cases comprised a 22-year-old pregnant woman with the gestational age of 31 weeks and a 25-year-old pregnant woman with the gestational age of 41 weeks. Both women were admitted to the Department of Maternal and Fetal Medicine at the Kyiv and Kharkiv municipal perinatal clinics. Patients were observed using standard fetal monitoring methods as well as the non-invasive fetal electrocardiogram. The non-invasive fetal electrocardiographic recordings were analyzed retrospectively, where it is possible to identify the presence of the atrioventricular block.

Conclusions

This study demonstrates, for the first time, the feasibility of the non-invasive fetal electrocardiogram as a supplementary method to diagnose of the fetal atrioventricular block. Combined with current fetal monitoring techniques, non-invasive fetal electrocardiography could support clinical decisions.

Reference Ranges of Fetal Cardiac Biometric Parameters Using Three-Dimensional Ultrasound with Spatiotemporal Image Correlation M Mode and Their Applicability in Congenital Heart Diseases

To determine reference values for fetal heart biometric parameters using the spatiotemporal image correlation (STIC) M mode and their applicability in congenital heart diseases (CHDs). A cross-sectional prospective study was conducted with 300 singleton pregnancies between 20 and 33 + 6 weeks of gestation. Right ventricular wall thickness (RVWT), interventricular septum thickness (IVST), and left ventricular wall thickness (LVWT) were measured off-line using the STIC-M mode with the cursor perpendicular to the interventricular septum. Polynomial regressions adjusted with the coefficient of determination (R ²) were performed. The curves were applied to 14 fetuses with structural CHD. For the reproducibility calculations, the concordance correlation coefficient (CCC) was used. The mean RVWT, IVST, and LVWT were 0.34 ± 0.09 cm, 0.28 ± 0.09 cm, and 0.30 ± 0.07 cm, respectively. There was correlation between RVWT, IVST, and LVWT and gestational age (GA): RVWT = -0.002 + 0.013 × GA (R ² = 0.33), IVST = -0.011 + 0.011 × GA (R ² = 0.25), and LVWT = 0.056 + 0.009 × GA (R ² = 0.26). RVWT, IVST, and LVWT were altered (<5th or >95th percentile) in 5/14, 5/14, and 7/14 of the fetuses with CHD, respectively. For RVWT, IVST, and LVWT, intra-observer (CCC = 0.86, 0.85, and 0.87, respectively) and inter-observer (CCC = 0.86, 0.86, and 0.86, respectively) reproducibility were good/moderate. The reference ranges determined for fetal heart biometric parameters using STIC-M had good intra- and inter-observer reproducibility and were applicable to fetuses with CHD.

Modification of distinct ion channels differentially modulates Ca2+ dynamics in primary cultured rat ventricular cardiomyocytes

Primary cultured cardiomyocytes show spontaneous Ca²⁺ oscillations (SCOs) which not only govern contractile events, but undergo derangements that promote arrhythmogenesis through Ca²⁺ -dependent mechanism. We systematically examined influence on SCOs of an array of ion channel modifiers by recording intracellular Ca²⁺ dynamics in rat ventricular cardiomyocytes using Ca²⁺ specific fluorescence dye, Fluo-8/AM. Voltage-gated sodium channels (VGSCs) activation elongates SCO duration and reduces SCO frequency while inhibition of VGSCs decreases SCO frequency without affecting amplitude and duration. Inhibition of voltage-gated potassium channel increases SCO duration. Direct activation of L-type Ca²⁺ channels (LTCCs) induces SCO bursts while suppressing LTCCs decreases SCO amplitude and slightly increases SCO frequency. Activation of ryanodine receptors (RyRs) increases SCO duration and decreases both SCO amplitude and frequency while inhibiting RyRs decreases SCO frequency without affecting amplitude and duration. The potencies of these ion channel modifiers on SCO responses are generally consistent with their affinities in respective targets demonstrating that modification of distinct targets produces different SCO profiles. We further demonstrate that clinically-used drugs that produce Long-QT syndrome including cisapride, dofetilide, sotalol, and quinidine all induce SCO bursts while verapamil has no effect. Therefore, occurrence of SCO bursts may have a translational value to predict cardiotoxicants causing Long-QT syndrome.

Prenatal pharmacogenomics: a promising area for research

Clinical applications of prenatal genetic screening currently focus on detection of aneuploidy and other genetic diseases in the developing fetus. Growing evidence suggests that the fetal genome may also be informative about fetal exposures, through contributions to placental transport as well as placental and fetal metabolism. Possible clinical applications of prenatal pharmacogenomic screening include prospective optimization of medication selection and dosage, as well as retrospective assessment of whether a fetus was previously exposed to significant risk. Newly available non-invasive methods of prenatal genetic screening mean that relevant fetal genotypes could be made available to obstetricians for use in management of a current pregnancy. This promising area for research merits more attention than it has thus far received.

Cardiotoxicity screening: a review of rapid-throughput in vitro approaches

Cardiac toxicity represents one of the leading causes of drug failure along different stages of drug development. Multiple very successful pharmaceuticals had to be pulled from the market or labeled with strict usage warnings due to adverse cardiac effects. In order to protect clinical trial participants and patients, the International Conference on Harmonization published guidelines to recommend that all new drugs to be tested preclinically for hERG (Kv11.1) channel sensitivity before submitting for regulatory reviews. However, extensive studies have demonstrated that measurement of hERG activity has limitations due to the multiple molecular targets of drug compound through which it may mitigate or abolish a potential arrhythmia, and therefore, a model measuring multiple ion channel effects is likely to be more predictive. Several phenotypic rapid-throughput methods have been developed to predict the potential cardiac toxic compounds in the early stages of drug development using embryonic stem cells- or human induced pluripotent stem cell-derived cardiomyocytes. These rapid-throughput methods include microelectrode array-based field potential assay, impedance-based or Ca(2+) dynamics-based cardiomyocytes contractility assays. This review aims to discuss advantages and limitations of these phenotypic assays for cardiac toxicity assessment.

Assessment of Cardiac Rate and Rhythm in Fetuses with Arrhythmia via Maternal Abdominal Fetal Electrocardiography

Objective This study aims to report our experience using the Monica AN24 (Monica Healthcare Ltd., Nottingham, United Kingdom), a maternal transabdominal fetal electrocardiographic monitor, in a case series of fetuses with arrhythmias. Study Design We recorded fetal electrocardiograms (fECGs) on subjects with fetal arrhythmias diagnosed by fetal echocardiogram. Fetal heart rate and rhythm were determined via manual fECG analysis. Results Overall, 20 fECGs were recorded from a pool of 13 subjects. Fetal heart rate acquisition was determined to be high, medium, and poor quality in 10, 3, and 7 tracings, respectively. High-quality tracings were obtained in 9 of 11 subjects with gestational age < 26 or > 34 weeks. P waves were detectable in five tracings. Conclusion In subjects < 26 or > 34 weeks' gestational age, there was reasonable success in fetal heart rate acquisition. Further study is warranted to determine the potential role of this device in the monitoring of subjects with fetal arrhythmias.

Drug resistant fetal arrhythmia in obstetric cholestasis

Obstetric cholestasis (OC) is a pregnancy specific liver disease characterized by increased levels of bile acid (BA) and pruritus. Raised maternal BA levels could be associated with intrauterine death, fetal distress, and preterm labor and also alter the rate and rhythm of cardiomyocyte contraction and may cause fetal arrhythmic events. We report a case of drug resistant fetal supraventricular tachycardia and concomitant OC. Conclusion. If there are maternal OC and concomitant fetal arrhythmia, possibility of the resistance to antiarrhythmic treatment should be kept in mind.

Abnormal sinoatrial node development resulting from disturbed vascular endothelial growth factor signaling

BACKGROUND

Sinus node dysfunction is frequently observed in patients with congenital heart disease (CHD). Variants in the Vascular Endothelial Growth Factor-A (VEGF) pathway are associated with CHD. In Vegf(120/120) mice, over-expressing VEGF120, a reduced sinoatrial node (SAN) volume was suggested. Aim of the study is to assess the effect of VEGF over-expression on SAN development and function.

METHODS

Heart rate was measured in Vegf(120/120) and wildtype (WT) embryos during high frequency ultrasound studies at embryonic day (E)12.5, 14.5 and 17.5 and by optical mapping at E12.5. Morphology was studied with several antibodies. SAN volume estimations were performed, and qualitative-PCR was used to quantify expression of genes in SAN tissues of WT and Vegf(120/120) embryos.

RESULTS

Heart rate was reduced in Vegf(120/120) compared with WT embryos during embryonic echocardiography (52 ± 17 versus 125 ± 31 beats per minute (bpm) at E12.5, p<0.001; 123 ± 37 vs 160 ± 29 bmp at E14.5, p=0.024; and 177 ± 30 vs 217 ± 34 bmp, at E17.5 p=0.017) and optical mapping (81 ± 5 vs 116 ± 8 bpm at E12.5; p=0.003). The SAN of mutant embryos was smaller and more vascularized, and showed increased expression of the fast conducting gap junction protein, Connexin43.

CONCLUSIONS

Over-expression of VEGF120 results in reduced heart rate and a smaller, less compact and hypervascularized SAN with increased expression of Connexin43. This indicates that VEGF is necessary for normal SAN development and function.

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.

Fetal bradycardia and sinus node dysfunction

The study reported here is a rare case of fetal sinus bradycardia that evolved into symptomatic bradycardia after birth, at which time the implantation of a cardiac pacemaker was indicated. Fetal echocardiography was used to diagnose the type of cardiac rhythm that caused the intra-uterine bradycardia, which enabled the initiation of the appropriate therapy approach and avoided an unnecessary interruption of the pregnancy. However, the details of the sinus bradycardia were impossible to determine in utero in this case due to sinus node dysfunction. After birth, the electrocardiogram results drew attention to a potentially unusual cause of sinus bradycardia, and enabled the diagnosis of this rare disease in this infant.

Postnatal outcome in patients with fetal tachycardia

The diagnosis and management of prenatal tachyarrhythmias is well established; however, the postnatal course and outcomes are not. The purpose of our study was to review the natural history of patients with fetal tachycardia, determine the incidence of postnatal arrhythmias, and determine whether there are factors to predict which fetuses will develop postnatal arrhythmias. A retrospective chart review of patients with fetal tachyarrhythmias investigated at British Columbia Children's and Women's Hospitals between 1983 and 2010 was conducted. Sixty-nine mother-fetus pairs were eligible for the study. Fifty-two had fetal supraventricular tachycardia, and 17 had fetal atrial flutter. Conversion to sinus rhythm occurred prenatally in 52 % of patients. Postnatal arrhythmia occurred in two thirds of patients, with 82 % of those cases occurring within the first 48 h of life. Hydrops fetalis, female sex, and lack of conversion to sinus rhythm was predictive of postnatal arrhythmia (P = 0.01, P = 0.01, and P = 0.001, respectively). Conversion to sinus rhythm prenatally did not predict postnatal arrhythmia. Median duration of treatment was 9 months. Two postnatal deaths of unknown etiology occurred. Two thirds of all patients with prenatal tachycardia will develop postnatal arrhythmia. Prenatal factors that predict postnatal arrhythmia include hydrops, sex, and whether or not conversion to sinus rhythm occurred prenatally. The majority of patients with postnatal arrhythmia present within 48 h of life, which has clinical implications for monitoring. Postnatal outcome is generally very good with most patients being weaned off medication in 6-12 months.

Surgical repair of atrial septal defect with severe pulmonary hypertension during pregnancy: a case report with literature review

We are reporting a case of a 37-year-old pregnant woman with a large secundum atrial septal defect with left-to-right shunt and severe pulmonary hypertension. Her atrial septal defect was undiagnosed before this pregnancy. After carefully considering all the options, we repaired her atrial septal defect with an open heart surgical closure at 20 weeks of gestation. A substantial and consistent reduction in pulmonary arterial pressure after the surgery and subsequent uneventful delivery indicate that surgical repair of atrial septal defects is a viable option that should be considered for such patients.

Pharmacotherapy in pregnancy; effect of ABC and SLC transporters on drug transport across the placenta and fetal drug exposure

Pharmacotherapy during pregnancy is often inevitable for medical treatment of the mother, the fetus or both. The knowledge of drug transport across placenta is, therefore, an important topic to bear in mind when deciding treatment in pregnant women. Several drug transporters of the ABC and SLC families have been discovered in the placenta, such as P-glycoprotein, breast cancer resistance protein, or organic anion/cation transporters. It is thus evident that the passage of drugs across the placenta can no longer be predicted simply on the basis of their physical-chemical properties. Functional expression of placental drug transporters in the trophoblast and the possibility of drug-drug interactions must be considered to optimize pharmacotherapy during pregnancy. In this review we summarize current knowledge on the expression and function of ABC and SLC transporters in the trophoblast. Furthermore, we put this data into context with medical conditions that require maternal and/or fetal treatment during pregnancy, such as gestational diabetes, HIV infection, fetal arrhythmias and epilepsy. Proper understanding of the role of placental transporters should be of great interest not only to clinicians but also to pharmaceutical industry for future drug design and development to control the degree of fetal exposure.

A GENS-based approach to cardiovascular pharmacology: impact on metabolism, pharmacokinetics and pharmacodynamics

Pharmacological outcomes depend on many factors, with many of them being sexually dimorphic. Thus, physiological gender/sex (GENS) differences can influence pharmacokinetics, pharmacodynamics and, thus, bioavailability and resulting in efficacy of treatment, meaning GENS differences should be an important consideration in therapeutics. In particular, drug response can change according to different hormonal environments. Therefore, GENS-specific differences have a particular clinical relevance in terms of drug delivery, especially for those substances with a narrow therapeutic margin. Since adverse effects are more frequent among women, safety is a key issue. Overall, the status of women, from a pharmacological point of view, is often different and less studied than that of men and deserves particular attention. Further studies focused on women's responses to drugs are necessary in order to make optimal pharmacotherapeutic decisions.

Safety of flecainide

Flecainide is a class Ic antiarrhythmic agent that has an important role as part of rhythm control strategies in patients with atrial fibrillation (AF). Early clinical data on the use of flecainide showed an increase in arrhythmias and mortality compared with placebo in patients with a previous myocardial infarction and asymptomatic or mildly symptomatic ventricular arrhythmias. These findings only apply to a specific group of patients with left ventricular dysfunction and ischaemic heart disease, but had a negative impact on the use of class Ic antiarrhythmics across all indications and patient groups. The aim of this review was to evaluate the available safety data for flecainide in the literature and to assess its current use in patients with AF. Current European guidelines now recommend the use of flecainide in carefully selected groups of patients with AF who do not have structural heart disease. This includes for the cardioversion of recent-onset AF, pretreatment prior to direct current cardioversion, out-of-hospital acute oral therapy ('pill-in-the-pocket' approach) and for the ongoing maintenance of sinus rhythm. Potential cardiac adverse effects of flecainide include proarrhythmia, conduction abnormalities and negative inotropic effects. Dizziness is the most frequent non-cardiac side effect, followed by blurred vision and difficulty focusing; these are almost all mild, transient and tolerable. Data from recent clinical trials in patients with supraventricular arrhythmias suggest that flecainide has a good tolerability profile in groups of appropriately selected patients. Caution is required when using flecainide in patients with renal dysfunction, and there are a number of drug interactions, but these are well documented and manageable. Overall, flecainide is a good choice for the pharmacological management of AF. It has a good safety record and low incidence of adverse effects, rare end-organ toxicity and a low risk of ventricular proarrhythmia. To ensure that the benefits of treatment outweigh any potential risks, careful patient selection and monitoring is required.

Evaluation of conventional Doppler fetal cardiac function parameters: E/A ratios, outflow tracts, and myocardial performance index

Structural evaluation of the fetal heart is well established. Functional evaluation using pulsed-wave Doppler may also be performed. E/A ratios express the relationship between the maximal velocities of the E and A waveforms of ventricular filling. In normal fetuses, E/A ratios are usually <1 but show a constant increment during gestation, mainly related to the increment of the E wave. In intrauterine growth restriction (IUGR) fetuses, E/A ratios are lower compared to values in normally grown fetuses at the same gestational age. Cardiac outflows provide information on the time-velocity integral that, combined with the vessel area, allows calculation of the left and right cardiac outputs. In normal fetuses there is a predominance of the right ventricle (55-60%) in contributing to the combined cardiac output. In IUGR fetuses this predominance shifts to the left ventricle in order to increase the flow to the upper part of the fetal body and brain. The myocardial performance index (MPI) also provides information on systolic and diastolic cardiac function. The MPI is an early and consistent marker of cardiac dysfunction which becomes altered in early stages of chronic hypoxia or in cases with cardiac overload such as in twin-to-twin transfusion syndrome.

Transplacental fetal therapy for junctional ectopic tachycardia

Junctional ectopic tachycardia (JET) is a rare type of tachyarrhythmia. A 39-year-old woman was transferred to our hospital for fetal tachyarrhythmia at 32 weeks' gestation. Fetal cardiac sonography revealed atrial and ventricular rates of 120-130 and 175-230 bpm, respectively, without 1:1 atrioventricular relationship. As ventricular tachycardia was considered to be the most probable diagnosis, transplacental therapy with digoxin and sotalol was done with partial response. Diagnosis of JET was made after birth. Although fetal JET is rare and prenatal diagnosis and treatment of this condition is still a challenge, differential diagnosis of fetal tachyarrhythmia should include this disorder.

The Foetal 'Mind' as a Reflection of its Inner Self: Evidence from Colour Doppler Ultrasound of Foetal MCA

The unborn healthy foetus is looked upon as a blessing by one and all. A plethora of thoughts arise in the brains of expectant parents. But what goes on in the brain of the yet unborn still remains a mystery. 'Foetal mind' is a reflection of functions of its organs of sense, an instrument of knowledge that may even be reduced to machine to demonstrate the effect of sense organs and brain contact. Testimony to this fact are the various waveform patterns obtained non-invasively from the foetal Middle Cerebral Artery (MCA) by using Colour Doppler Ultrasound. Our study, conducted for evaluating the foetal MCA in a rural obstetric population in Maharashtra, India, explains how the MCA - a major artery supplying foetal brain, can give abundant information about foetal heart and foetal stress. When only the foetal heart is stressed by the presence of arrhythmias or ectopic beats, these changes are manifest in the foetal MCA velocity waveform pattern as seen on Colour Doppler study. When the entire foetus is under stress, as in cases of intra uterine growth retardation (IUGR), changes again manifest in the foetal MCA velocity waveform pattern and are designated as the foetal Brain Sparing Effect. Thus scientific evaluation of foetal MCA waveform can objectively demonstrate that the overtly non-communicating foetal brain indeed remains an internal organ of sense and a vital instrument of knowledge to clarify the various effects of sense organs and brain contact. Although the brain parenchyma or cerebral metabolism has not been studied here, cerebral vessels serve as a window to cerebral metabolism, as auto regulatory function of brain leads to changes in haemodynamics of cerebral vessels. Also, like other vessels, MCA mirrors foetal distress and IUGR; but unlike other vessels, e.g. the umbilical or uterine artery, which show these changes in the form of reduction or even reversal of diastolic flow, MCA shows an increase in diastolic component due to brain sparing effect. The unique connection between physical changes in the foetal heart, brain and mental operations are thus critically clarified to some extent, and this helps untangle and comprehend the lattice of mental operations. Although this preliminary study has its limitations, it still carries forward the present corpus of knowledge on the strength of its evidential and critical enquiry and helps unravel the concept of foetal consciousness.

[Class I antiarrhythmic drugs: mechanisms, contraindications, and current indications]

Class I antiarrhythmic drugs are sodium channel inhibitors that act by slowing myocardial conduction and, thus, interrupting or preventing reentrant arrhythmia. Due to proarrhythmic effects and the risk of ventricular tachyarrhythmia, class I antiarrhythmics should not be administered in patients with structural heart disease. Nevertheless, there remains a broad spectrum of arrhythmias--among the most common being atrial fibrillation--that can successfully be treated with class I antiarrhythmic drugs. This review gives an overview on the classification, antiarrhythmic mechanisms, indications, side effects, and application modes of class I antiarrhythmic drugs.