Correlation of maternal flecainide concentrations and therapeutic effect in fetal supraventricular tachycardia

Favourable outcome for hydrops or cardiac failure associated with fetal tachyarrhythmia: a 20-year review

BACKGROUND

Prognosis of fetuses with hydrops and tachyarrhythmia has been portrayed as poor in most published reports. This might lead to biased counselling, unnecessary caesarean section, preterm delivery, and even termination of pregnancy.

AIMS

To evaluate contemporary fetal and postnatal outcomes of hydropic fetuses with fetal tachyarrhythmia when it is treated effectively and monitored systematically.

METHODS

This is a retrospective review of a single centre experience at the University Hospital of Wales over a 20-year period. All fetuses received high doses of flecainide and digoxin combination treatment. Tachycardia response rate, time to arrhythmia and hydrops resolution, fetal and postnatal morbidity, and mortality rates were analysed.

RESULTS

Twenty fetuses were diagnosed with hydrops fetalis and received treatment. The mechanism of fetal tachyarrhythmia was supraventricular tachycardia in thirteen and atrial flutter in eight cases. Among the 20 fetuses treated, the overall tachycardia response rate was 90% (18/20) with the restoration of sinus rhythm in 85% (17/20) of the cases. The median time to restore sinus rhythm or to rate control of the arrhythmia was 1.5 days (range 12 hours to 13 days). Hydrops resolved in 17 of the 20 fetuses, with a median time of 12 days (range 3-21 days). Four fetuses went into spontaneous preterm birth and one fetus was delivered early due to worsening hydrops. No significant neurological morbidity was observed in surviving neonates and infants on clinical examination. There was one postnatal death due to respiratory complications of prematurity in the non-responsive supraventricular tachycardia case.

CONCLUSIONS

High-dose flecainide and digoxin combination offers effective treatment strategy in fetuses with hydrops and tachyarrhythmia with favourable outcomes. This study may guide more realistic counselling for pregnancies complicated by tachyarrhythmia and hydrops.

Fetal Tachyarrhythmia Management from Digoxin to Amiodarone-A Review

Sustained fetal tachycardias are rare but represent a high risk of mortality and morbidity. Consensus has yet to be found regarding their optimal management. The aim of this narrative review is to summarize the data available in the current literature regarding the efficacy and safety of medications used in the management of intrauterine tachyarrhythmias and to provide possible treatment protocols. In this review, we would like to emphasize the importance of a thorough evaluation of both the fetus and the mother, prior to transplacental antiarrhythmic drug initiation. Factors such as the hemodynamic status of the fetus, possible mechanisms of fetal arrhythmia, and concomitant maternal conditions are of primordial importance. As a possible treatment protocol, we would like to recommend the following: due to the risk of sustained supraventricular tachycardia (SVT), fetuses with frequent premature atrial beats should be evaluated more frequently by echocardiography. A careful hemodynamic evaluation of a fetus with tachycardia is primordial in forestalling the appearance of hydrops. In the case of atrial flutter (AFL), sotalol therapy could represent a first choice, whereas when dealing with SVT patients, flecainide should be considered, especially for hydropic patients. These data require consolidation through larger scale, non-randomized studies and should be handled with caution.

Transition of maternal serum concentration of digoxin and flecainide in the third trimester-A case report of fetal supraventricular tachycardia with hydrops

When transplacental therapy is conducted, the maternal serum concentrations of digoxin and flecainide may fluctuate throughout third trimester. Therefore, TDM may be effective in improving the efficacy and safety of treatment.

Outcomes of sustained fetal tachyarrhythmias after transplacental treatment

Background

Fetal tachyarrhythmia is a condition that may lead to cardiac dysfunction, hydrops, and death. Despite a transplacental treatment, failure to obtain or maintain sinus rhythm may occur.

Objective

We aimed to analyze the perinatal outcomes of sustained fetal tachyarrhythmias after in utero treatment.

Methods

We performed a retrospective evaluation of 69 cases with sustained fetal tachyarrhythmia. We compared the perinatal and long-term outcomes of prenatally converted and drug-resistant fetuses. Tachyarrhythmia subtypes were also evaluated.

Results

Conversion to sinus rhythm was obtained in 74% of cases; 26% of cases were drug-resistant and delivered arrhythmic. Three perinatal deaths occurred in both groups (6.7% vs 17%, P = .34). Neonates delivered arrhythmic were more frequently admitted to neonatal intensive care units (75% vs 31%, P < .01), and their hospital stay was longer (20.9 vs 6.64 days, P < .001). Multiple neonatal recurrences (81% vs 11%, P < .001), temporary hemodynamic dysfunction or heart failure (50% vs 6.7%, P < .001), and postnatal use of a combination treatment (44% vs 13%, P = .028) were also more frequent in this population. Beyond the neonatal period, rates of recurrences within the first 16 months were higher in drug-resistant fetuses (HR = 16.14, CI 95% [4.485; 193.8], P < .001). In this population, postnatal electrocardiogram revealed an overrepresentation of rare mechanisms, especially permanent junctional reciprocating tachycardia (PJRT) (31%).

Conclusion

Prenatal conversion to stable sinus rhythm is a major determinant of perinatal and long-term outcomes in fetal tachyarrhythmias. The underlying electrophysiological mechanisms have a major role in predicting these differential outcomes with an overrepresentation of PJRT in the drug-resistant population.

Low mortality in fetal supraventricular tachycardia: Outcomes in a 30-year single-institution experience

OBJECTIVES

To describe a single institutional experience managing fetuses with supraventricular tachycardia (SVT) and to identify associations between patient characteristics and fetal and postnatal outcomes.

BACKGROUND

Sustained fetal SVT is associated with significant morbidity and mortality if untreated, yet the optimal management strategy remains unclear.

METHODS

Retrospective cohort study including fetuses diagnosed with sustained SVT (>50% of the diagnostic echocardiogram) between 1985 and 2018. Fetuses with congenital heart disease were excluded.

RESULTS

Sustained SVT was diagnosed in 65 fetuses at a median gestational age of 30 weeks (range, 14-37). Atrioventricular re-entrant tachycardia and atrial flutter were the most common diagnoses, seen in 41 and 16 cases, respectively. Moderate/severe ventricular dysfunction was present in 20 fetuses, and hydrops fetalis was present in 13. Of the 57 fetuses initiated on transplacental drug therapy, 47 received digoxin first-line, yet 39 of 57 (68%) required advanced therapy with sotalol, flecainide, or amiodarone. Rate or rhythm control was achieved in 47 of 57 treated fetuses. There were no cases of intrauterine fetal demise. Later gestational age at fetal diagnosis (odds ratio [OR], 1.1, 95% confidence interval [CI], 1.01-1.2, P = .02) and moderate/severe fetal ventricular dysfunction (OR, 6.1, 95% CI, 1.7-21.6, P = .005) were associated with postnatal SVT. Two postnatal deaths occurred.

CONCLUSIONS

Fetuses with structurally normal hearts and sustained SVT can be effectively managed with transplacental drug therapy with minimal risk of intrauterine fetal demise. Treatment requires multiple antiarrhythmic agents in over half of cases. Later gestational age at fetal diagnosis and the presence of depressed fetal ventricular function, but not hydrops, predict postnatal arrhythmia burden.

Sotalol as an effective adjunct therapy in the management of supraventricular tachycardia induced fetal hydrops fetalis

Sustained fetal supraventricular tachycardia (SVT) complicated by hydrops fetalis carries a significant risk of morbidity and mortality. While there is no clear consensus on first- and second-line therapy options for the management of fetal SVT with or without hydrops fetalis, there exists significant nonrandomized experience with a number of antiarrhythmic agents that has founded the basis for management. Furthermore, recently published meta-analyses and ongoing multicenter prospective studies have aimed to bridge the gap in the literature. We report two cases of sustained fetal SVT with severe secondary hydrops fetalis managed successfully with flecainide-sotalol combination therapy in one case and sotalol-digoxin combination therapy in the second and review the literature for the management of fetal SVT.

Flecainide: Electrophysiological properties, clinical indications, and practical aspects

Over the last 35 years, flecainide proved itself one of the most commonly used arrhythmic drugs, expanding its original indication for ventricular arrhythmias and results nowadays as the cornerstone of the rhythm control strategy in atrial fibrillation management of patients without structural heart disease. While the increased mortality associated with flecainide in the Cardiac Arrhythmia Suppression Trial (CAST) still casts his shadow over flecainide clinical profile, this compound has subsequently demonstrated safe and is now used successfully for a plethora of indications, including pharmacological cardioversion of atrial fibrillation, cathecolaminergic polymorphic ventricular tachycardia, supraventricular tachyarrhythmias and ventricular pre-excitation. Moreover, the recent marketing of a controlled release formulation, along with the intravenous and immediate release formulations, increased the armamentarium to the clinician's disposal while improving patients' compliance. In the present paper, we offer a comprehensive review of the anti-arrhythmic effects of flecainide, detailing its electrophysiological properties, its effects on the conduction system, its clinical use and the major side effects and contraindications in clinical practice.

Flecainide is a safe and effective treatment for pre-excited atrial fibrillation rapidly conducted to the ventricle in pregnant women: a case series

Background

Pregnancy is associated with an increased incidence of cardiac arrhythmias likely due to hormonal, haemodynamic, and autonomic changes. Yet, there is little data available regarding the efficacy and safety of anti-arrhythmic agents to prevent pre-excited atrial fibrillation (AF) in pregnant women.

Case summary

We report on three pregnant women who developed AF rapidly conducted to the ventricle through an overt accessory pathway as the first manifestation of Wolff–Parkinson–White syndrome.

Discussion

All patients were treated with flecainide with neither arrhythmias recurrence nor adverse events of the treatment. Mechanisms of action and clinical efficacy of flecainide are discussed.

Maternal monitoring and safety considerations during antiarrhythmic treatment for fetal supraventricular tachycardia

Fetal tachycardia is a rare complication during pregnancy. After exclusion of maternal and fetal conditions that can result in a secondary fetal tachycardia, supraventricular tachycardia is the most common cause of a primary sustained fetal tachyarrhythmia. In cases of sustained fetal supraventricular tachycardia, maternal administration of digoxin, flecainide, sotalol, and more rarely amiodarone, is considered. As these medications have the potential to cause significant adverse effects, we sought to examine maternal safety during transplacental treatment of fetal supraventricular tachycardia. In this narrative review we summarize the literature addressing pharmacologic properties, monitoring, and adverse reactions associated with medications most commonly prescribed for transplacental therapy of fetal supraventricular tachycardia. We also describe maternal monitoring practices and adverse events currently reported in the literature. In light of our findings, we provide clinicians with a suggested maternal monitoring protocol aimed at optimizing safety.

Fetal dysrhythmias

Fetal dysrhythmias are common abnormalities, usually manifesting as irregular rhythms. Although most irregularities are benign and caused by isolated atrial ectopics, in a few cases, rhythm irregularity may indicate partial atrioventricular block, which has different etiological and prognostic implications. We provide a flowchart for the initial management of irregular rhythm to help select cases requiring urgent specialist referral. Tachycardias and bradycardias are less frequent, can lead to hemodynamic compromise, and may require in utero therapy. Pharmacological treatment of tachycardia depends on the type (supraventricular tachycardia or atrial flutter) and presence of hydrops, with digoxin, flecainide, and sotalol being commonly used. An ongoing randomized trial may best inform about their efficacy. Bradycardia due to blocked bigeminy normally resolves spontaneously, but if it is due to established complete heart block, there is no effective treatment. Ongoing research suggests hydroxychloroquine may reduce the risk of autoimmune atrioventricular block. Sinus bradycardia (rate <3rd centile) may be a prenatal marker for long-QT syndrome.

Prenatal therapy for fetal cardiac disorders

Fetal cardiac abnormalities are some of the commonest congenital disorders seen in prenatal life. They can be anatomical or functional and can develop de novo or as a consequence of either maternal or fetal disease. Untreated, morbidity and mortality rates are high for hypoplastic left heart disorders and for some fetal tachy and bradyarrhythmias. Optimum management strategies are often not clear because of the lack of knowledge about the precise natural history of some of these conditions. Prenatal therapy ranges from invasive fetal cardiac intervention to maternal administration of drugs for transplacental transfer to the fetus. This comprehensive review covers many fetal cardiac disorders and various prenatal therapeutic options that are available.