Differential diagnosis and management of the fetus and newborn with an irregular or abnormal heart rate

Diagnosis and Management of Fetal Arrhythmias in the Current Era

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 bradyarrhythmia causing hydrops fetalis: A journey from fetal echo to autopsy

Introduction

Non-immune hydrops fetalis is a condition with poor fetal prognosis. The incidence of this clinical condition is increasing as compared to its iso-immune variant. The diagnosis of hydrops fetalis is straightforward; however, delineating the primary cause of non-immune hydrops fetalis requires a holistic approach and background knowledge of the entity.

Case report

We present a case of non-immune hydrops fetalis due to a rare functional cardiac disorder demonstrated by features of cardiac failure in the form of clinically significant tricuspid regurgitation detected on echocardiography. Fetal autopsy supported the diagnosis by excluding any structural anomaly.

Discussion

Non-immune hydrops fetalis may be due to structural and non-structural cardiac anomalies. Meticulous work-up is required to establish the diagnosis in such cases.

Conclusion

The case also highlights the systematic approach as well as the series of investigations required for the early diagnosis and management of such cases.

Diagnosis and Management of Fetal Autoimmune Atrioventricular Block

Autoimmune congenital atrioventricular block (CAVB) has been extensively studied in recent decades. The American Heart Association published guidelines for monitoring pregnant women with anti-Ro/Sjögren’s syndrome antigen A (SSA) or anti-La/Sjögren’s syndrome antigen B (SSB) autoantibodies, which are considered to increase the risk of CAVB. Information about the natural history of the disease in utero has contributed to the detection of fetuses with CAVB in the treatable stage. Hydroxychloroquine (HCQ) may be used to prevent CAVB. The lack of large randomized control trials is a major drawback to fully confirm the benefits of fluorinated steroids such as dexamethasone. Although, when combined with a β-sympathomimetic agent, the outcome of administering a fluorinated steroid in complete CAVB is still controversial. Novel treatments targeting the immunological process might prevent the recurrence of CAVB in pregnant women with previously affected children.

A case series of neonatal arrhythmias

OBJECTIVE

Neonatal arrhythmias (NAs) are defined as abnormal heart rates in the neonatal period. They may occur as a result of various cardiovascular, systemic and metabolic problems.

METHODS

A retrospective chart review was performed on newborns who were diagnosed with NA during hospitalization in a neonatal intensive care unit (NICU), or who were admitted to the NICU because of an arrhythmia diagnosis in two NICUs in Turkey from May 2011 to June 2013.

RESULTS

Seventeen neonates with arrhythmias were identified. The incidence of NA was 0.4% and 0.3% in the two NICUs, and was 0.37% in the study population as a whole. Mean gestational age was 37 (29-40) weeks. Nine of the infants (53%) were diagnosed with fetal arrhythmia (FA) during the last week of gestation. The distribution of NA types was as follows: six (35%) supraventricular tachycardia (SVT), six (35%) premature atrial contractions (PACs), two (11%) premature ventricular contractions (PVCs), two (11%) multiple arrhythmias such as SVT + PAC and AV block + PVC, and one (5%) AV block. Wolff-Parkinson-White syndrome was present in one patient. An association of NA with congenital heart malformations was identified in five cases.

CONCLUSIONS

Cardiac arrhythmias are important causes of infant morbidity, and an occasional cause of infant mortality if undiagnosed and untreated. It is important for the physician to be aware of the etiology, development and natural history of arrhythmias in the fetal and neonatal period.

Pediatric prenatal diagnosis of congenital heart disease

PURPOSE OF REVIEW

Fetal cardiology is a rapidly evolving field. Imaging technology continues to advance as do approaches to in-utero interventions and care of the critically ill neonate, with even greater demand for improvement in prenatal diagnosis of congenital heart disease (CHD) and arrhythmias.

RECENT FINDINGS

Reviewing the advances in prenatal diagnosis of CHD in such a rapidly developing field is a broad topic. Therefore, we have chosen to focus this review of recent literature on challenges in prenatal detection of CHD, challenges in prenatal counseling, advances in fetal arrhythmia diagnosis, and potential benefits to patients with CHD who are identified prenatally.

SUMMARY

As methods and tools to diagnose and manage CHD and arrhythmias in utero continue to improve, future generations will hopefully see a reduction in both prenatal and neonatal morbidity and mortality. Prenatal diagnosis can and should be used to optimize location and timing of delivery and postnatal interventions.

Nonimmune hydrops fetalis part I: etiology and pathophysiology

Nonimmune hydrops fetalis (NIHF) is a condition in which excess fluid has accumulated in the fetal interstitial spaces as a result of one or more nonimmune factors. A plethora of maternal, placental, and fetal disease processes have been associated with NIHF. Knowledge of the various etiologies of NIHF and how the disease process affects fluid homeostasis is important for planning patient care and counseling families of patients diagnosed with nonimmune hydrops fetalis. This article discusses the mechanisms governing fluid distribution in the extracellular spaces, examines the various etiologies associated with NIHF, and describes the pathogenesis of NIHF for each etiologic category.

A surprising case of sustained antenatal fetal bradycardia

Persistent fetal bradycardia noted in the antenatal period can occur secondary to maternal conditions, fetal cardiac structural defects, or from congenital heart block. Fetal bradycardia can be mistaken for maternal pulse and should be confirmed with ultrasound whenever possible. Prompt evaluation of the fetus with bradycardia can lead to early interventions designed to prevent cardiac damage and/or hydrops.