Treatment, not delivery, of the late preterm and term fetus with supraventricular arrhythmia

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.

Prenatal Diagnosis of Congenital Heart Disease: The Crucial Role of Perinatal and Delivery Planning

Although most congenital heart defects (CHDs) are asymptomatic at birth, certain CHD lesions are at significant risk of severe hemodynamic instability and death if emergent cardiac interventions are not performed in a timely fashion. Therefore, accurate identification of at-risk fetuses and appropriate delivery resource planning according to the degree of anticipated hemodynamic instability is crucial. Fetal echocardiography has increased prenatal CHD detection in recent years due to advancements in ultrasound techniques and improved obstetrical cardiac screening protocols, enabling the prediction of newborns' hemodynamic status. This assessment can guide multidisciplinary resource planning for postnatal care, including selection of delivery site, delivery room management, and transport to a cardiac center based on CHD risk severity. This review will discuss fetal cardiovascular physiology and the circulatory changes that occur at the time of and immediately following birth, outline fetal echocardiographic findings used to risk-stratify newborns with CHDs, and outline principles for neonatal resuscitation and initial transitional care in neonates with these complex CHD lesions.

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

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

Maturity makes sense: managing supraventricular tachyarrhythmia in the late preterm and term fetus

Linked article: This Editorial comments on Holmes et al. Click here to view the article.