Successful prenatal management of ventricular tachycardia and second-degree atrioventricular block in fetal long QT syndrome

Fetal Long QT Syndrome - Challenges in Perinatal Management: A Review and Case Report. Induction of Labor and Vaginal Birth Under Continuous Magnesium Therapy

Congenital LQTS is an often undetected inherited cardiac channel dysfunction and can be a reason for intrauterine fetal demise. It can present in utero as CTG and ultrasound abnormalities, i. e., bradycardia, ventricular tachycardia, or fetal hydrops. Diagnosis is made by CTG, echocardiography, or fMCG. Intrauterine therapy with a ß blocker and i. v. magnesium should be started. Our objective was to examine the current knowledge about diagnosis and treatment of LQTS and in particular to highlight the opportunity of vaginal birth under continuous intravenous magnesium therapy. Therefore, a thorough MEDLINE and Google Scholar search was conducted. Randomized controlled trials, meta-analyses, prospective and retrospective cohort trials, and case reports were considered. We showed the possibility of vaginal delivery under continuous magnesium therapy in a case of suspected fetal LQTS. A stepwise concept for diagnosis, monitoring, and peripartum management in low, intermediate, and high risk cases of fetal LQTS is presented. If risk is low or intermediate, a vaginal delivery under continuous monitoring is reasonable. Induction of labor at term should be evaluated.

Fetal Bradycardia Caused by Monogenic Disorders-A Review of the Literature

Introduction: The standard obstetric definition of fetal bradycardia is a sustained fetal heart rate < 110 bpm over at least 10 min. Fetal bradycardia can be the first and only prenatal presentation of a heart disease. We present an overview on different genetic disorders that should be taken into consideration in case of diagnosed fetal bradycardia. Methods: A literature review was conducted using a PubMed- and OMIM-based search for monogenetic disorders causing fetal bradycardia in September 2022. Results: The review on the literature identified nine monogenic diseases that could lead to fetal bradycardia. Four of these disorders can be associated with extracardiac findings. Discussion: Genetic testing should be considered in cases with fetal bradycardia, especially in cases of additional extracardiac findings. Broad sequencing techniques and improved prenatal phenotyping could help to establish a diagnosis in an increasing number of cases.

Fetal ventricular tachycardia: betablockers should be the first line treatment

Ventricular tachycardia (VT) is a rare cause of tachycardia during the fetal life. Coexistence of VT with sinus bradycardia or second-degree heart block strongly suggests long QT syndrome (LQTS) [1-3] and needs to administrate to the mother beta-blockers and in some cases magnesium sulfate [1,2,4]. When there is no argument for a LQTS several drugs have been proposed, most of them contraindicated in LQTS. We present a case of fetal LQTS with fetal VT and cardiac insufficiency with no antenatal clue for LQTS, successfully managed with propranolol. Thus, we suggest that in case of isolated fetal VT (i.e. without tumor or cardiomyopathy) beta blockers (excluding sotalol) should be the first line treatment since LQTS can be a possible cause for the dysrhythmia.

Noninvasive Fetal Electrocardiography in the Diagnosis of Long QT Syndrome: A Case Series

INTRODUCTION

Early detection and monitoring for malignant arrhythmias is fundamental to prenatal care in long QT syndrome (LQTS). Recently, we studied the feasibility of isolating the fetal electrocardiogram (fECG) and measuring electrocardiographic intervals with a noninvasive fECG device using blind source separation with reference signal. Our aim was to evaluate the ability of fECG to diagnose LQTS.

CASE PRESENTATIONS

We identified 3 cases of clinically suspected LQTS based on fetal echocardiogram (2 had sinus bradycardia, 1 had second-degree atrioventricular block with negative maternal anti-SSA/SSB antibody titers). With institutional review board approval, these patients were prospectively enrolled for fECG acquisition. Offline post-processing generated fECG waveforms and calculated QT intervals. Case 1 and 3 had a maternal history of LQTS. Two of the three fetuses with suspected LQTS had confirmed LQTS by postnatal ECG and genetic testing. FECG was able to identify a prolonged corrected QT interval in both cases. One of these also had fetal magnetocardiography (fMCG), which yielded similar findings to the fECG. The third fetus had a normal fECG; fMCG and postnatal ECG were also normal.

CONCLUSIONS

In 3 cases, fECG findings corroborated the diagnosis of LQTS. Noninvasive fECG may offer a novel method for fECG that is portable and more clinically accessible.

Fetal arrhythmias: diagnosis and treatment

Fetal arrhythmias are common, and they may resolve spontaneously in majority of the cases. Sustained fetal arrhythmias associated with major structural heart disorders, hydrops fetalis, and fetal heart failure warrant intrauterine pharmaceutical conversion of heart rhythm or early pacemaker implant in order to avoid fetal demise. Fetal atrial flutter (AF) and supraventricular tachycardia (SVT) resemble in terms of the effects of intrauterine therapies. Digoxin is more suitable for rhythm conversion of fetal AF and SVT in fetuses free of hydrops fetalis, while sotalol shows better effects for those with hydrops fetalis. In fetal cases of atrioventricular blocks, an etiological treatment for the maternal antibody exposure by steroids could be an alternative remedy. In this article, the clinical diagnosis and treatment of fetal arrhythmias are presented, and advantages and disadvantages of antiarrhythmic agents for fetal arrhythmias are compared.