Preventing and Treating Torsades de Pointes in the Mother, Fetus and Newborn in the Highest Risk Pregnancies with Inherited Arrhythmia Syndromes

Abstract

The number of women of childbearing age who have been diagnosed in childhood with ion channelopathy and effectively treated using beta blockers, cardiac sympathectomy, and life-saving cardiac pacemakers/defibrillators is increasing. Since many of these diseases are inherited as autosomal dominant, offspring have about a 50% risk of having the disease, though many will be only mildly impacted during fetal life. However, highly complex delivery room preparation is increasingly needed in pregnancies with inherited arrhythmia syndromes (IASs). However, specific Doppler techniques show meanwhile a better understanding of fetal electrophysiology. The advent of fetal magnetocardiography (FMCG) now allows the detection of fetal Torsades de Pointes (TdP) ventricular tachycardia and other LQT-associated arrhythmias (QTc prolongation, functional second AV block, T-wave alternans, sinus bradycardia, late-coupled ventricular ectopy and monomorphic VT) in susceptible fetuses during the second and third trimester. These types of arrhythmias can be due to either de novo or familial Long QT Syndrome (LQTS), Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT), or other IAS. It is imperative that the multiple specialists involved in the antenatal, peripartum, and neonatal care of these women and their fetuses/infants have the optimal knowledge, training and equipment in order to care for these highly specialized pregnancies and deliveries. In this review, we outline the steps to recognize symptomatic LQTS in either the mother, fetus or both, along with suggestions for evaluation and management of the pregnancy, delivery, or post-partum period impacted by LQTS.

Advancements in the diagnosis and management of premature ventricular contractions in pediatric patients

“…Family history and genetic predisposition play a critical role in the epidemiology of PVCs. Familial clustering of ventricular arrhythmias and the identification of causative mutations in genes encoding cardiac ion channels and structural proteins emphasize the importance of genetic counseling and family screening in affected individuals ( 24 ).…”

Diagnosis and Management of Fetal Arrhythmias in the Current Era

“…atrial enlargement, limb abnormalities, sinus bradycardia, and first-degree atrioventricular block), NKX2.5 mutations (Figure 6), LQTS and other heritable channelopathies or inherited bradycardia syndromes, fetal CNS abnormalities, fetal severe growth restriction or distress, and umbilical cord compression (usually transient and iatrogenic from the ultrasound probe) [2,9,66]. No treatment is recommended for fetal sinus or low atrial bradycardia, but diagnostic evaluation and monitoring are recommended [2].…”

“…Fetal diagnosis of LQTS and other channelopathies can decrease the risk for intrauterine fetal demise and premature delivery (sinus bradycardia or ventricular bradycardia due to functional 2 • -AV block is often misinterpreted as fetal distress), can allow for fetal therapy (even the hydropic fetus with ventricular tachycardia can be successfully treated in utero) and maternal avoidance of QTc prolonging medications (oxytocin and ondansetron) to prevent fetal torsades, and can identify affected family members without apparent symptoms (Figure 10) [65]. Ventricular tachycardia associated with LQTS and other channelopathies can be treated in utero with transplacental IV magnesium (first-line therapy), propranolol, lidocaine, and/or mexiletine [66,80]. ondansetron) to prevent fetal torsades, and can identify affected family members without apparent symptoms (Figure 10) [65].…”

“…Ventricular tachycardia associated with LQTS and other channelopathies can be treated in utero with transplacental IV magnesium (first-line therapy), propranolol, lidocaine, and/or mexiletine [66,80]. A management approach to fetal sinus bradycardia and suspected channelopathy, includes periodic echocardiograms (every 2 weeks × 2 and then every 4 weeks until delivery), home fetal heart rate monitoring (2-3 times daily to detect 2:1 AV block or torsades), periodic biophysical profiles (especially to assess the baseline fetal heart rate prior to labor and delivery), and fetal magnetocardiography (fMCG) to measure the QTc and evaluate for late premature ventricular contractions or torsades (Figure 11) [66,76,77]. It also important to obtain parental EKGs, review the maternal medication list for any QT prolonging drugs, and correct low maternal calcium, magnesium, and 25-OH-vitamin D levels [2].…”

“…Cascade genetic testing is recommended for parents and first-degree relatives of positive cases [9]. Because of the very significant association between fetal sinus bradycardia and channelopathies, Chaudhry-Waterman et al have recommended genetic testing for infants with a history of FHR <3rd percentile for gestational age even if the postnatal ECG demonstrated a normal QTc interval [9]; some experts also advocate for amniocentesis and prenatal genetic A management approach to fetal sinus bradycardia and suspected channelopathy, includes periodic echocardiograms (every 2 weeks × 2 and then every 4 weeks until delivery), home fetal heart rate monitoring (2-3 times daily to detect 2:1 AV block or torsades), periodic biophysical profiles (especially to assess the baseline fetal heart rate prior to labor and delivery), and fetal magnetocardiography (fMCG) to measure the QTc and evaluate for late premature ventricular contractions or torsades (Figure 11) [66,76,77]. It also important to obtain parental EKGs, review the maternal medication list for any QT prolonging drugs, and correct low maternal calcium, magnesium, and 25-OH-vitamin D levels [2].…”