The Study of Antiarrhythmic Medications in Infancy (SAMIS)

Outcomes of Infant Supraventricular Tachycardia Management Without Medication

Most infants presenting with supraventricular tachycardia (SVT) are treated with an antiarrhythmic, primarily to prevent unrecognized future episodes that could lead to tachycardia-induced cardiomyopathy. A common practice at our institution is to not treat after the first presentation of infant SVT and instead educate parents on heart rate monitoring and reasons to present to care. The goal of this study was to evaluate the outcomes of non-pharmacologic treatment of infant SVT at first presentation and compare to outcomes of infants treated with an antiarrhythmic. This was a retrospective single center study of all infants presenting with a first episode of SVT from 2014 to 2021. Excluded were patients with a non-reentry type tachyarrhythmia, atrial flutter, long-RP tachycardia, congenital heart disease, or abnormal ventricular function. Sixty-four infants were included in the study. Thirty-six were managed without an antiarrhythmic. SVT recurred in 28% of the non-treatment group vs 50% in those treated with antiarrhythmics, p = 0.12. Of the patients admitted to the hospital, those in the non-treatment group had a shorter length of stay, 1(IQR 1-1) vs 3(IQR 2-4) days, p < 0.01. Non-treated patients were less likely to present to the emergency department for recurrent SVT, 6% vs 32%, p < 0.01. Neither group had a patient develop tachycardia-induced cardiomyopathy. For infants with structurally and functionally normal hearts, non-treatment combined with parental education after the first episode of SVT does not lead to worse outcomes. This approach avoids the burden of medication administration in an infant and may have the added benefit of empowering parents to feel comfortable managing clinically insignificant tachycardia at home.

Sotalol prophylaxis was efficient and safe for supraventricular tachycardia in early infancy

AIM

There is no consensus on the best prophylaxis for supraventricular tachycardia (SVT) in infancy. We studied the efficacy and safety of sotalol.

METHOD

This retrospective study comprised infants diagnosed with SVT before 1 year of age and treated with sotalol during 2002-2018 in Stockholm, Sweden. The patients' characteristics, comorbidities, sotalol dosages, QT intervals and outcomes were extracted from their medical records.

RESULTS

We studied 85 infants (65% boys) with a median age of eight (range 0-288) days at the time of diagnosis, including 78 with re-entry tachycardia. Sotalol was completely or partially successful in the 67/75 patients who completed the treatment, as well as in four of the seven patients with other tachycardia mechanisms. The 48 infants with postnatal debut had significantly higher success rates than the 27 with foetal debut (96% vs. 78%, p = 0.04). Prolongation of corrected QT (QTc) intervals of ≥450 ms occurred in 16% of the total cohort and two patients with QTc intervals of ≥500 ms had their treatment changed. There were no cases of proarrhythmia after sotalol treatment.

CONCLUSION

Sotalol provided effective and safe prophylaxis for SVT during infancy. QTc prolongation rarely caused treatment discontinuation and there were no cases of proarrhythmia.

Calcium channel blockers and beta blockers in pediatric supraventricular tachycardia

INTRODUCTION

Supraventricular tachycardia (SVT) is a common pediatric arrhythmia. Beta blockers (BBs) and calcium channel blockers (CCBs) are used for treatment despite little data examining their use. We describe the prescriptive tendencies, efficacy, and tolerability of BBs and CCBs used in the treatment of pediatric SVT.

METHODS AND RESULTS

This is a multicenter retrospective cohort study from three academic children's hospitals. Individuals aged 1-21 years at time of SVT diagnosis initiated on a BB or a CCB between 01/01/2010 and 12/31/2020 were included. Exclusion criteria were pre-excitation, ectopic atrial tachycardia, and hemodynamically significant heart disease. Demographic, comorbidity, symptomatology, and medication data were collected. Treatment success was defined using a composite data abstraction tool. Of 164 patients, 151 received a BB and 13 received a CCB. The success rate on the initial dosage was 46% for both BB and CCB; the success rate following dosage adjustments was also comparable for BBs (98/151, 65%) and CCBs (9/13, 69%). While 27 (18%) BB patients experienced intolerable side effects, no CCB patient did.

CONCLUSION

Treatment with a BB or CCB was successful in half of patients. BBs were prescribed more frequently than CCBs but were associated with more side effects.

Outcomes in Infants with Supraventricular Tachycardia: Risk Factors for Readmission, Recurrence and Ablation

Supraventricular tachycardia (SVT) is the most common arrhythmia in infants. Once diagnosed, infants are admitted for antiarrhythmic therapy and discharged after observation. There are limited data on risk factors for readmission and readmission rates, while on medication. The objective of this study was to investigate risk factors for readmission and outcomes in infants diagnosed with SVT. This is a single-center retrospective study over a 10-year period of infants under 6 months of age with documented SVT. Infants with congenital heart disease requiring surgical or catheter intervention, gestational age less than 32 weeks or diagnosis of atrial flutter or fibrillation were excluded. The primary outcome was readmission within 31 days of hospital discharge. Long term need for ablation and eventual discontinuation of medications were assessed. Ninety patients were included. Beta blockers were the initial therapy in 66 and 28 required a medication change. Nineteen were readmitted within 31 days of discharge. The only clinical factor associated with early readmission was presence of ventricular pre-excitation (6/19 vs. 8/71, p = 0.03). Patients who were readmitted within 31 days had a longer length of treatment (12 [11.5, 22.0] vs. 10 [7.5, 12.0] months, p = 0.007) and were more likely to undergo ablation (4/19 vs. 2/71, p = 0.017). In this cohort of infants with SVT, readmission was common and ventricular pre-excitation was identified as a risk factor for readmission. Infants who were readmitted within 31 days of discharge had longer length of antiarrhythmic therapy and were more likely to undergo catheter ablation.

Pediatric Beta Blocker Therapy: A Comprehensive Review of Development and Genetic Variation to Guide Precision-Based Therapy in Children, Adolescents, and Young Adults

Beta adrenergic receptor antagonists, known as beta blockers, are one of the most prescribed medications in both pediatric and adult cardiology. Unfortunately, most of these agents utilized in the pediatric clinical setting are prescribed off-label. Despite regulatory efforts aimed at increasing pediatric drug labeling, a majority of pediatric cardiovascular drug agents continue to lack pediatric-specific data to inform precision dosing for children, adolescents, and young adults. Adding to this complexity is the contribution of development (ontogeny) and genetic variation towards the variability in drug disposition and response. In the absence of current prospective trials, the purpose of this comprehensive review is to illustrate the current knowledge gaps regarding the key drivers of variability in beta blocker drug disposition and response and the opportunities for investigations that will lead to changes in pediatric drug labeling.

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.

Diagnosis and Management of Paroxysmal Supraventricular Tachycardia

Importance

Paroxysmal supraventricular tachycardia (PSVT), defined as tachyarrhythmias that originate from or conduct through the atria or atrioventricular node with abrupt onset, affects 168 to 332 per 100 000 individuals. Untreated PSVT is associated with adverse outcomes including high symptom burden and tachycardia-mediated cardiomyopathy.

Observations

Approximately 50% of patients with PSVT are aged 45 to 64 years and 67.5% are female. Most common symptoms include palpitations (86%), chest discomfort (47%), and dyspnea (38%). Patients may rarely develop tachycardia-mediated cardiomyopathy (1%) due to PSVT. Diagnosis is made on electrocardiogram during an arrhythmic event or using ambulatory monitoring. First-line acute therapy for hemodynamically stable patients includes vagal maneuvers such as the modified Valsalva maneuver (43% effective) and intravenous adenosine (91% effective). Emergent cardioversion is recommended for patients who are hemodynamically unstable. Catheter ablation is safe, highly effective, and recommended as first-line therapy to prevent recurrence of PSVT. Meta-analysis of observational studies shows single catheter ablation procedure success rates of 94.3% to 98.5%. Evidence is limited for the effectiveness of long-term pharmacotherapy to prevent PSVT. Nonetheless, guidelines recommend therapies including calcium channel blockers, β-blockers, and antiarrhythmic agents as management options.

Conclusion and Relevance

Paroxysmal SVT affects both adult and pediatric populations and is generally a benign condition. Catheter ablation is the most effective therapy to prevent recurrent PSVT. Pharmacotherapy is an important component of acute and long-term management of PSVT.

Pediatric antiarrhythmics and toxicity: A clinical review

Antiarrhythmic medications are fundamental in the acute and chronic management of pediatric arrhythmias. Particularly in the pediatric patient population, associated antiarrhythmic toxicities represent important potential adverse effects. Emergency medicine clinicians must be skilled in the detection, workup, and management of antiarrhythmic toxicity. This is a clinical review of the indications, pharmacology, adverse effects, and toxicologic treatment of antiarrhythmics commonly used in the pediatric patient population.

Flecainide administration in children: dosage, drug levels, and clinical effect

Therapeutic drug monitoring of flecainide in children using plasma concentration measurements is undertaken by some clinicians. There is very little published evidence surrounding factors which influence plasma flecainide concentration, particularly in paediatric populations. We undertook a retrospective study of 45 children receiving flecainide to identify factors that influence its plasma concentration. Patients receiving a dose of 6 mg/kg/day had a higher mean plasma flecainide concentration than those receiving lower doses. Younger age and lighter weight were also associated with higher plasma flecainide concentrations. Children aged younger than 1 year receiving flecainide three times a day had a higher mean plasma flecainide concentration than older children who received flecainide twice a day. All supratherapeutic levels occurred in children aged less than 1 year who were receiving flecainide three times a day. Supratherapeutic levels were more common in those receiving 6 mg/kg/day while subtherapeutic levels were more common in those receiving 2 mg/kg/day. A supratherapeutic level did not correlate with adverse effects or clinical toxicity. Our results would suggest the need for a change of practice from prescribing flecainide at a frequency of three times a day in children aged younger than 1 year to twice a day in line with other ages.

Triple Antiarrhythmic Therapy in Newborns with Refractory Atrioventricular Reentrant Tachycardia

Atrioventricular reentrant tachycardia (AVRT) is the most common form of supraventricular tachycardia in newborns. AVRT is sometimes refractory to conventional antiarrhythmic therapy. We describe our experience about the use of the triple combination of flecainide + propranolol + amiodarone as third-line regimen for refractory and recurrent AVRT in newborns. We considered a series of 14 patients who had failed both first-line and second-line therapy and were treated using the combination of flecainide + propranolol + amiodarone. Transoesophageal electrophysiologic study (TES) was performed to test the effectiveness of medical therapy during hospitalization and to try to reduce the amount of therapy, after amiodarone wash-out, before 1 year of age. TES was repeated at 1 year of age to test the spontaneous resolution of the arrhythmia after treatment discontinuation. Rhythm control was achieved in all 14 patients. At a mean age of 9.3 ± 2 months, AVRT was not inducible by TES in 11/12 amiodarone-free patients. At a mean age of 14.1 ± 3 months, AVRT was still inducible in 7/12 patients after interrupting the entire antiarrhythmic therapy (58.3%). Triple combination was effective as third-line option to suppress AVRT refractory to single and double antiarrhythmic therapy, with no significant adverse events. Our experience suggests that triple therapy could be maintained for a short-term treatment, discontinuing amiodarone before 1 year of age to avoid long-term side effects. Newborns who needed triple therapy appear to have a lower chance of accessory pathway disappearance at 1 year of age. TES could be useful for risk stratification of recurrences at the time of drug discontinuation in infants considered to be at higher risk of recurrent AVRT.

Multicenter cohort study on duration of antiarrhythmic medication for supraventricular tachycardia in infants

Antiarrhythmic medication (AM) is commonly used to prevent supraventricular tachycardia (SVT) recurrence in infants. Our aim was to determine whether a shorter duration of AM is sufficient to prevent atrioventricular reentrant tachycardia (AVRT) recurrence and evaluate risk factors for recurrence of SVT after discontinued AM.This multicenter cohort study included all infants diagnosed with SVT in the five university hospitals in Finland between 2005 and 2017. Those diagnosed between 2005 and 2012 received AM for 12 months (group 1), and those diagnosed between 2013 and 2017 received AM for 6 months (group 2). A total of 278 infants presented with AVRT (group 1, n = 181; group 2, n = 97), and the median AM duration was 12.0 months (interquartile range [IQR] 11.4-13.4) and 7.0 months (IQR 6.0-10.2), respectively. Propranolol was the most frequently used first-line AM (92% and 95%). Recurrence-free survival rates were over 88% until 12 months after AM prophylaxis in both groups, without any statistically significant difference between them. Independent risk factors for recurrence of SVT after discontinuation of AM were need of combination AM (HR 2.2, 95% CI 1.14-4.20), Wolff-Parkinson-White (WPW) syndrome (HR 2.4, 95% CI 1.25-4.59), and age over 1 month at admission (HR 2.2, 95% CI 1.12-4.48).    Conclusion: Shortening AM duration in infants from 12 to 6 months does not seem to lead to more frequent SVT recurrence. The risk factors for recurrence of SVT were WPW syndrome, need of combination AM, and age over 1 month.

Clinical Predictors of Recurrent Supraventricular Tachycardia in Infancy

BACKGROUND

Data regarding recurrence risk among infants with supraventricular tachycardia (SVT) are limited.

OBJECTIVES

The purpose of this study was to determine incidence and factors associated with SVT recurrence.

METHODS

This was a retrospective single-center study (1984-2020) with prospective phone follow-up of infants with structurally normal hearts diagnosed at age ≤1 year with re-entrant SVT. Primary outcome was first SVT recurrence after hospital discharge. Classification and regression tree analysis was performed to determine a risk algorithm.

RESULTS

Among 460 infants (62% male), 87% were diagnosed at ≤60 days of age (median 13 days; IQR: 1-31 days). During a median follow-up of 5.2 years (IQR: 1.8-11.2 years), 33% had recurrence. On multivariable analysis, factors associated with recurrence included: fetal or late (>60 days) diagnosis (HR: 1.90; 95% CI: 1.26-2.86; and HR: 1.73; 95% CI: 1.07-2.77, respectively), Wolff-Parkinson-White (WPW) syndrome (HR: 2.46; 95% CI: 1.75-3.45), and need for multi-antiarrhythmic or second-line therapy (HR: 2.08; 95% CI: 1.45-2.99). Based on the classification and regression tree analysis, WPW incurred the highest risk. Among those without WPW, age at diagnosis was the most important factor predicting risk. Fetal or late diagnosis incurred higher risk, and if multi-antiarrhythmic or second-line therapy was also required, risk nearly doubled. Infants without WPW, who were diagnosed early (0-60 days), and who were discharged on propranolol were at lowest recurrence risk.

CONCLUSIONS

Infants with SVT are most likely to be diagnosed at ≤60 days and be male. Risk factors for recurrence (occurred in 33%), present at time of diagnosis, include WPW, fetal or late diagnosis, and multi-antiarrhythmic or second-line therapy. Infants with early diagnosis, without WPW, and discharged on first-line monotherapy are at lowest recurrence risk.

Fetal Arrhythmia Diagnosis and Pharmacologic Management

One of the most successful achievements of fetal intervention is the pharmacologic management of fetal arrhythmias. This management usually takes place during the second or third trimester. While most arrhythmias in the fetus are benign, both tachy- and bradyarrhythmias can lead to fetal hydrops or cardiac dysfunction and require treatment under certain conditions. This review will highlight precise diagnosis by fetal echocardiography and magnetocardiography, the 2 primary means of diagnosing fetuses with arrhythmia. Additionally, transient or hidden arrhythmias such as bundle branch block, QT prolongation, and torsades de pointes, which can lead to cardiomyopathy and sudden unexplained death in the fetus, may also need pharmacologic treatment. The review will address the types of drug therapies; current knowledge of drug usage, efficacy, and precautions; and the transition to neonatal treatments when indicated. Finally, we will highlight new assessments, including the role of the nurse in the care of fetal arrhythmias. The prognosis for the human fetus with arrhythmias continues to improve as we expand our ability to provide intensive care unit-like monitoring, to better understand drug treatments, to optimize subsequent pregnancy monitoring, to effectively predict timing for delivery, and to follow up these conditions into the neonatal period and into childhood. Coordinated initiatives that facilitate clinical fetal research are needed to address gaps in knowledge and to facilitate fetal drug and device development.

Evaluation of Clinical Course and Maintenance Drug Treatment of Supraventricular Tachycardia in Children During the First Years of Life. A Cohort Study from Eastern Germany

Supraventricular tachycardia (SVT) is considered the most common cause of arrhythmia in children and infants. Regarding the likelihood of a spontaneous resolution of SVTs during the first years of life, drug treatment aims to bridge the time until children 'grow out' out of the arrhythmia. The choice of antiarrhythmic agents and the planning of maintenance therapy are mainly based on clinical experience and retrospective single- and multi-institutional analyses and databases from all over the world approaching differently to this topic. The current study aimed to evaluate the clinical course, pharmacological treatment strategies, and constellations of risk for recurrences in the management of SVTs in children aged 3 < years. The database of the Heart Center Leipzig, Department of Pediatric cardiology, was searched for pediatric patients aged < 3 years with a clinically documented SVT between 2000 and 2019 that received pharmacologic treatment. Patients with complex congenital heart disease or arrhythmias following cardiac surgery were excluded. 69 patients were included. Pharmacologic treatment, follow-up schedule, recurrences, outcomes, and risk factors for complicated courses are reported. Drug therapy of SVTs in young children remains a controversial topic with heterogeneous treatment and follow-up strategies applied. Risk factors for recurrences and/or stubborn clinical courses are difficult rhythm control with 3 or more antiarrhythmic drugs, ectopic atrial tachycardias, and a first occurrence of the SVT in the fetal period. Prospective studies are needed to sufficiently evaluate optimal treatment strategies.

Medical Management of Infants With Supraventricular Tachycardia: Results From a Registry and Review of the Literature

Background

Several medication choices are available for acute and prophylactic treatment of refractory supraventricular tachycardia (SVT) in infants. There are almost no controlled trials, and medication choices are not necessarily evidence based. Our objective was to report the effectiveness of management strategies for infant SVT.

Methods

A registry of infants admitted to hospital with re-entrant SVT and no haemodynamically significant heart disease were prospectively followed at 11 international tertiary care centres. In addition, a systematic review of studies on infant re-entrant SVT in MEDLINE and EMBASE was conducted. Data on demographics, symptoms, acute and maintenance treatments, and outcomes were collected.

Results

A total of 2534 infants were included: n = 108 from the registry (median age, 9 days [0-324 days], 70.8% male) and n = 2426 from the literature review (median age, 14 days; 62.3% male). Propranolol was the most prevalent acute (61.4%) and maintenance treatment (53.8%) in the Registry, whereas digoxin was used sparingly (4.0% and 3.8%, respectively). Propranolol and digoxin were used frequently in the literature acutely (31% and 33.2%) and for maintenance (17.8% and 10.1%) (P < 0.001). No differences in acute or prophylactic effectiveness between medications were observed. Recurrence was higher in the Registry (25.0%) vs literature (13.4%) (P < 0.001), and 22 (0.9%) deaths were reported in the literature vs none in the Registry.

Conclusion

This was the largest cohort of infants with SVT analysed to date. Digoxin monotherapy use was rare amongst contemporary paediatric cardiologists. There was limited evidence to support one medication over another. Overall, recurrence and mortality rates on antiarrhythmic treatment were low.

Antiarrhythmic Medication in Neonates and Infants with Supraventricular Tachycardia

Supraventricular tachycardia (SVT) is the most common arrhythmia in neonates and infants, and pharmacological therapy is recommended to prevent recurrent episodes. This retrospective study aims to describe and analyze the practice patterns, effectiveness, and outcome of drug therapy for SVT in patients within the first year of life. Among the 67 patients analyzed, 48 presented with atrioventricular re-entrant tachycardia, 18 with focal atrial, and one with atrioventricular nodal re-entrant. Fetal tachycardia was reported in 27%. Antiarrhythmic treatment consisted of beta-receptor blocking agents in 42 patients, propafenone in 20, amiodarone in 20, and digoxin in 5. Arrhythmia control was achieved with single drug therapy in 70% of the patients, 21% needed dual therapy, and 6% triple. Propafenone was discontinued in 7 infants due to widening of the QRS complex. After 12 months (6-60), 75% of surviving patients were tachycardia-free and discontinued prophylactic treatment. Patients with fetal tachycardia had a significantly higher risk of persistent tachycardia (p: 0.007). Prophylactic antiarrhythmic medication for SVT in infancy is safe and well tolerated. Arrhythmia control is often achieved with single medication, and after cessation, most patients are free of arrhythmias. Infants with SVT and a history of fetal tachycardia are more prone to suffer from persistent SVT and relapses after cessation of prophylactic antiarrhythmic medication than infants with the first episode of SVT after birth.

Impact of Digoxin Use on Interstage Outcomes of Single Ventricle Heart Disease (From a NPC-QIC Registry Analysis)

Digoxin has been associated with lower interstage mortality (ISM) following stage 1 palliation (S1P). Despite a substantial increase in digoxin use nationally, ISM has not declined. We aimed to determine the impact of digoxin on ISM in the current era. This study analyzed data from the National Pediatric Cardiology Quality Improvement Collaborative (NPC-QIC) registry. All patients who survived to hospital discharge following S1P were included. Comparisons were made between pre-specified eras (1: 2010-2015, 2: 2016-2019) based on digoxin use. ISM risk was estimated using the previously published NEONATE score (excluding digoxin). Multivariable Cox proportional hazard models assessed the impact of digoxin on ISM and freedom from unplanned readmission in era 2. A total of 1400 (46.8%) patients were included from era 1 and 1589 (53.2%) from era 2. Digoxin use (22.4% vs 61.7%, p < 0.001) and the proportion of high-risk patients (9.1% vs 20.3%, p < 0.001) increased across eras. There was no difference in predicted ISM risk between those who did vs did not receive digoxin in era 2 (p = 0.82). In era 2, digoxin use was independently associated with lower ISM (AHR 0.60, 95%CI 0.36 to 0.98, p = 0.043) and greater freedom from unplanned readmission (AHR 0.44, 95%CI 0.32 - 0.59, p < 0.001). In conclusion, digoxin is independently associated with lower ISM and greater freedom from interstage readmission. The lack of improvement in overall ISM in the current era may be secondary to a greater proportion of high-risk patients and/or disproportionately higher digoxin use in lower risk patients, who may not derive the same benefit.

Supraventricular tachycardias in neonates and infants: factors associated with fatal or near-fatal outcome

Prognosis of supraventricular tachycardias in neonates and infants is thought to be excellent with rare fatal outcomes. Nevertheless, initial management can be challenging. The aim of this study was to perform a retrospective analysis in neonates/infants with non-pos-toperative supraventricular tachycardias regarding risk factors for clinical outcome and type of antiarrhythmic drug therapy. The data of 157 patients aged < 1 year who presented between 2000 and 2015 with symptomatic tachycardias were retrospectively reviewed. Pharmacological therapy was successful in 151 patients (96%); 1 patient (1%) required catheter ablation and 5 patients (3%) died (1 death linked to hemodynamical reasons after effective arrhythmia control). Serious complications following acute medical therapy occurred in 4 patients of survivors. Patients with complications or death had a lower bodyweight, more frequent intrauterine tachycardia, transplacental therapy, urgent caesarian section, higher PRISM II score, longer period to control tachycardia, more frequent proarrhythmia, and major adverse event-defined as life-threatening event without a documented new arrhythmia-compared to the group without complications. There was no significant difference between the groups regarding prematurity, structural heart disease, and type of tachycardia. Proarrhythmia occurred in 6 cases and was related to intravenous drug use with class IC antiarrhythmics in 3/6 cases, digoxin in 2/6 cases, and amiodarone in 1/6 cases. ECG signs of impending proarrhythmia without new-onset arrhythmia requiring cessation of therapy were detected in 6 patients.Conclusion: Although rare, non-post-operative supraventricular tachycardia in neonates and infants might be a serious disease. Acute intravenous pharmacological treatment to control tachycardia might pose a risk for fatal or near-fatal outcome. Detection of proarrhythmia related to class IC antiarrhythmics in neonates might be especially difficult and requires alertness. What is Known • Prognosis of supraventricular tachycardias in children are thought to be excellent with fatal outcomes being rare. • Mortality is increased in the very young and in those with structural heart disease. What is New • Complicated outcome of non-post-operative supraventricular tachycardias in neonates is associated with lower bodyweight, age, prenatal tachycardia, higher PRISM II score, longer period to control tachycardia, and proarrhythmia. • Detection of class IC proarrhythmic effect is especially difficult in neonates because of their narrow QRS and warrants alertness.

Impact of Perioperative Tachydysrhythmias on Mortality and Length of Stay in Complete Repair of Tetralogy of Fallot: A Multicenter Retrospective Cohort Study from the Pediatric Health Information System

INTRODUCTION

Tachydysrhythmias (TDS) frequently occur after complete repair of tetralogy of Fallot (TOF). However, not much is known about the effect of TDS on morbidity and mortality after TOF repair. We sought to assess the associations between TDS and mortality and morbidity after repair of TOF using a multicentre database.

MATERIALS AND METHODS

We identified all children aged 0-5 years in the Pediatric Health Information System who underwent TOF repair between 2004 and 2015. Codes for TDS were used to identify cases. Outcome variables were inpatient mortality and total length of stay (LOS). Univariate and multiple logistic and linear regression analyses were used to identify the effects of multiple risk factors, including TDS, on mortality and LOS.

RESULTS

A total of 7,749 patients met inclusion criteria, of which 1,493 (19%) had codes for TDS. There was no association between TDS and inpatient mortality. However, TDS were associated with 1.1 days longer LOS and accounted for 2% of the variation observed in LOS.

CONCLUSION

After complete repair of TOF, TDS were not associated with mortality and appeared to have only a modest effect on LOS.

Supraventricular tachycardias in the first year of life: what is the best pharmacological treatment? 24 years of experience in a single centre

Background

Supraventricular tachycardias (SVTs) are common in the first year of life and may be life-threatening. Acute cardioversion is usually effective, with both pharmacological and non-pharmacological procedures. However, as yet no international consensus exists concerning the best drug required for a stable conversion to sinus rhythm (maintenance treatment). Our study intends to describe the experience of a single centre with maintenance drug treatment of both re-entry and automatic SVTs in the first year of life.

Methods

From March 1995 to April 2019, 55 patients under one year of age with SVT were observed in our Centre. The SVTs were divided into two groups: 45 re-entry and 10 automatic tachycardias. As regards maintenance therapy, in re-entry tachycardias, we chose to start with oral flecainide and in case of relapses switched to combined treatment with beta-blockers or digoxin. In automatic tachycardias we first administered a beta-blocker, later combined with flecainide or amiodarone when ineffective.

Results

The patients’ median follow-up time was 35 months. In re-entry tachycardias, flecainide was effective as monotherapy in 23/45 patients (51.1%) and in 20/45 patients (44.4%) in combination with nadolol, sotalol or digoxin (overall 95.5%). In automatic tachycardias, a beta-blocker alone was effective in 3/10 patients (30.0%), however, the best results were obtained when combined with flecainide: overall 9/10 (90%).

Conclusions

In this retrospective study on pharmacological treatment of SVTs under 1 year of age the combination of flecainide and beta-blockers was highly effective in long-term maintenance of sinus rhythm in both re-entry and automatic tachycardias.

Antiarrhythmic Treatment Duration and Tachycardia Recurrence in Infants with Supraventricular Tachycardia

We sought to assess the effect of a shorter medication treatment course (up to 4-6 months of age) on the recurrence of infantile supraventricular tachycardia (SVT). This was a retrospective review of infants with SVT diagnosed at age 0-12 months at Rady Children's Hospital (2010-2017). Infants with structural congenital heart disease, automatic tachycardias, atrial flutter, or lack of follow-up data were excluded. Seventy-four infants met criteria. Median age at diagnosis was 6 days (IQR 0-21 days); 28.4% presented with fetal tachycardia. Median gestational age was 38.4 weeks (IQR 36-40), 30% were preterm. Median age at medication discontinuation was 6.7 months (IQR 4.6-9.8). Therapy was stopped at younger age in patients managed by pediatric electrophysiologist (vs. general pediatric cardiologist): 4.9 vs. 8.6 months (p = 0.03). Thirty-eight patients (51.4%) were treated for < 6 months; 32.4% for 6-12 months, and 16.2% for > 12 months. SVT recurrence was similar for these groups: 13.2% vs. 16.7%, and 33.3%, respectively, (p = 0.27). Most patients with recurrence required emergency care, though none had significant adverse outcomes. Infants with SVT and structurally normal cardiac anatomy, who remain recurrence free on a single agent, have no increased risk of recurrence with shorter treatment courses of 4-6 months, compared to traditional treatment duration of 6-12 months.

Supraventricular tachyarrhythmias during the intrauterine, neonatal, and infant period: A 10-year population-based study

BACKGROUND

We aimed to evaluate the incidence, type, and management of supraventricular tachyarrhythmias (SVT) during the first year of life in a retrospective, population-based, single-center study during a 10-year period.

METHODS

The analyzed patient cohort is based on data from the only specialized center managing all cases of neonatal and infant SVTs between 2009 and 2018 in the Slovak Republic (5.5 million population). A total of 116 consecutive patients <366 days old were included in the study.

RESULTS

Calculated SVT incidence ratio was 1:4500 in the first year of life. AV reentry tachycardia was the leading arrhythmia (49%). SVT in this specific population was frequently a transient problem with spontaneous resolution in 87% of patients during a median 3-year follow up. Congenital heart disease was common (16%). Intrauterine treatment by drugs administered to mother was safe and effective in preventing unnecessary cesarean deliveries. In arrhythmia termination, amiodarone and propafenone were equally safe and effective, with possible more favorable pharmacodynamics of the former. For prophylactic treatment, sotalol and propafenone were equally safe and effective and became the preferred basis of long-term drug therapy in our center. However, this therapy requires intensive monitoring during its initiation.

CONCLUSION

The prognosis of SVT in the first year of life is good: with optimized pharmacological treatment, the need for early catheter ablation and mortality rate are low (<1%) and there is a high rate of spontaneous arrhythmia resolution. Heart failure is a possible predictor of arrhythmia persistence with need for ablation in later life.

A systematic review of population pharmacokinetic analyses of digoxin in the paediatric population

This is a PROSPERO registered systematic review (CRD42018105207), conducted to summarize the available knowledge regarding the population pharmacokinetics of digoxin in paediatrics and to identify the sources of variability in its disposition. PubMed, ISI Web of Science, SCOPUS and Science Direct databases were searched from inception to January 2019. All paediatric population pharmacokinetic studies of digoxin that utilized the nonlinear mixed-effect modelling approach were incorporated in this review, and data were synthesized descriptively. After application of the inclusion-exclusion criteria 8 studies were included. Most studies described digoxin pharmacokinetics as a 1-compartment model with only 1 study describing its pharmacokinetics as 2-compartments. Age was an important predictor of clearance in studies involving neonates or infants, other predictors of clearance were weight, height, serum creatinine, coadministration of spironolactone and presence of congestive heart failure. Congestive heart failure was also associated with an increased volume of distribution in 1 study. The estimated value of apparent clearance in a typical individual standardized by mean weight ranged between 0.24 and 0.56 L/h/kg, the interindividual variability in clearance ranged between 7.0 and 35.1%. Half of the studies evaluated the performance of their developed models via external evaluation. In conclusion, substantial predictors of digoxin pharmacokinetics in the paediatric population in addition to model characteristics and evaluation techniques are presented. For clinicians, clearance could be predicted using age especially in neonates or infants, weight, height, serum creatinine, coadministration of medications and disease status. For future researchers, designing pharmacokinetic studies that allow 2-compartment modelling and linking pharmacokinetics with pharmacodynamics is recommended.

Trends in the off-label use of β-blockers in pediatric patients

The use of US Food and Drug Administration (FDA)-approved drugs for the treatment of an unapproved indication or in an unapproved age group, or at doses or route of administration not indicated on the label is known as off-label use. Off-label use may be beneficial in circumstances when the standard-of-care treatment has failed, and/or no other FDA-approved medications are available for a particular condition. In pediatric patients, off-label use may increase the risk of adverse events as pharmacokinetic and pharmacodynamic data are limited in children. Approximately 73% of off-label drugs currently prescribed for various conditions do not have sufficient scientific evidence for safety and efficacy. For example, β-blockers are a class of drugs with FDA-approval for very few indications in pediatrics but are commonly used for various off-label indications. Interestingly, the proportion of off-label use of β-blockers in adults is at about 52% (66.2 million) of the total number of β-blockers prescribed. The frequency of off-label use of β-blockers in children is also high with limited data on the indications as well as safety and efficacy. We present trends in off-label use of β-blockers in children to discuss drug safety and efficacy and include recommendations for pediatric providers.

A Novel and Simple Algorithm Using Surface Electrocardiogram That Localizes Accessory Conduction Pathway in Wolff-Parkinson-White Syndrome in Pediatric Patients

Background

The location of the accessory pathway (AP) can be precisely identified on surface electrocardiography (ECG) in adults with Wolff-Parkinson-White (WPW) syndrome. However, current algorithms to locate the AP in pediatric patients with WPW syndrome are limited.

Objective

To propose an optimal algorithm that localizes the AP in pediatric patients with WPW syndrome.

Methods

From 1992 to 2016, 180 consecutive patients aged below 18 years with symptomatic WPW syndrome were included. After the exclusion of patients with non-descriptive electrocardiography (ECG), multiple APs, congenital heart diseases, non-inducible tachycardia, and those who received a second ablation, 104 patients were analyzed retrospectively. Surface ECG was obtained before ablation and evaluated by using previously documented algorithms, from which a new pediatric algorithm was developed.

Results

Previous algorithms were not highly accurate when used in pediatric patients with WPW syndrome. In the new algorithm, the R/S ratio of V1 and the polarity of the delta wave in lead I could distinguish right from the left side AP with 100% accuracy. The polarity of the delta wave of lead V1 could distinguish free wall AP from septal AP with an accuracy of 100% in left-side AP, compared to 88.6% in leads III and V1 for right-side AP. The overall accuracy was 92.3%.

Conclusions

This simple, novel algorithm could differentiate left from right AP and septal from free wall AP in pediatric patients with WPW syndrome.

Neonatal supraventricular tachycardia

Supraventricular tachycardia (SVT) is one of the most common conditions requiring emergency cardiac care in neonates. Atrioventricular reentrant tachycardia utilizing an atrioventricular bypass tract is the most common form of SVT presenting in the neonatal period. There is high likelihood for spontaneous resolution for most of the common arrhythmia substrates in infancy. Pharmacological agents remain as the primary therapy for neonates.

A comparison of oral flecainide and amiodarone for the treatment of recurrent supraventricular tachycardia in children

BACKGROUND

Supraventricular tachycardia (SVT) in children can be difficult to treat when first-line therapies (beta-blockade or digoxin) are not effective. Both flecainide and amiodarone are used as second-line therapies. We sought to compare the efficacy and safety of flecainide and amiodarone in pediatric patients with recurrent SVT.

METHODS

Pediatric patients treated with oral flecainide or oral amiodarone for SVT between 2006 and 2015 were studied. Tachycardia mechanisms included orthodromic reciprocating tachycardia (ORT), intra-atrial reentrant tachycardia (IART), and ectopic atrial tachycardia (EAT). Outcomes were classified as full success, partial success (requiring additional intervention), or failure.

RESULTS

Seventy-four patients were included (median age 46 days, range 1 day to 19 years). Flecainide was used in 47 patients and amiodarone in 27 patients. Full success was achieved in 68% and 59%, respectively (P = 0.28). Partial success was achieved in 13% and 19%, respectively (P = 0.12). Treatment failed in 19% and 22%, respectively (P = 0.97). Ten crossover patients received the second medication after the first failed. Of five amiodarone-to-flecainide crossovers, four achieved success on flecainide alone. Of five flecainide-to-amiodarone crossovers, two achieved success. Minor adverse events occurred in 9% of flecainide and 22% of amiodarone patients (P = 0.16). No significant differences were seen by arrhythmia subtype (36 EAT, 28 ORT, 10 IART), congenital heart disease (n = 38), or age group (56 infants).

CONCLUSIONS

Oral flecainide and amiodarone achieved meaningful arrhythmia control in 81% and 78% of pediatric patients with recurrent SVT, respectively. Those who failed amiodarone had encouraging outcomes when changed to flecainide.

Propranolol: A 50-Year Historical Perspective

Propranolol is a beta-adrenergic receptor antagonist that was developed by the British scientist Sir James Black primarily for the treatment of angina pectoris, more than 50 years ago. It was not long before several other cardiovascular as well as noncardiovascular therapeutic uses of propranolol were discovered. Propranolol soon became a powerful tool for physicians in the treatment of numerous conditions such as hypertension, cardiac arrhythmias, myocardial infarction, migraine, portal hypertension, anxiety, essential tremors, hyperthyroidism, and pheochromocytoma. Owing to its action at multiple receptor sites, propranolol exerts several central and peripheral effects and is therefore useful in various conditions. Right from reduction in postmyocardial mortality to control of anxiety in performers, propranolol plays an important role in a plethora of medical conditions. Interestingly, even today, newer indications of this age-old drug are being discovered. Moreover, propranolol treatment has been found to be cost-effective when compared to other corresponding treatment options for individual indications. In this article, we attempt to recount the journey of propranolol right from its inception to the present day.

Management of Supraventricular Tachycardia in Infants

Supraventricular tachycardia is the most common tachyarrhythmia encountered in infants. In older children and adults, definitive treatment of the supraventricular tachycardia substrate with catheter ablation is a common approach to management. However, in infants, the risks of catheter ablation are significantly higher, and the patients often outgrow the potential to experience episodes. Therefore, antiarrhythmic medications are often utilized to minimize the likelihood of experiencing episodes. This article reviews the common arrhythmia mechanisms encountered in infants and the medications used to treat these patients.

Neonatal arrhythmias: diagnosis, treatment, and clinical outcome

Arrhythmias in the neonatal period are not uncommon, and may occur in neonates with a normal heart or in those with structural heart disease. Neonatal arrhythmias are classified as either benign or nonbenign. Benign arrhythmias include sinus arrhythmia, premature atrial contraction, premature ventricular contraction, and junctional rhythm; these arrhythmias have no clinical significance and do not need therapy. Supraventricular tachycardia, ventricular tachycardia, atrioventricular conduction abnormalities, and genetic arrhythmia such as congenital long-QT syndrome are classified as nonbenign arrhythmias. Although most neonatal arrhythmias are asymptomatic and rarely life-threatening, the prognosis depends on the early recognition and proper management of the condition in some serious cases. Precise diagnosis with risk stratification of patients with nonbenign neonatal arrhythmia is needed to reduce morbidity and mortality. In this article, I review the current understanding of the common clinical presentation, etiology, natural history, and management of neonatal arrhythmias in the absence of an underlying congenital heart disease.

Propranolol Versus Digoxin in the Neonate for Supraventricular Tachycardia (from the Pediatric Health Information System)

Conflicting data exist for the appropriate management of a neonate with supraventricular tachycardia (SVT). We sought to assess postnatal prescribing trends for neonates with SVT and to evaluate if there were therapy-specific mortality and resource utilization benefits. Nationally distributed data from 44 pediatric hospitals in the 2004 to 2015 Pediatric Health Information System database were used to identify patients admitted at ≤2 days of age with structurally normal hearts and treated with an antiarrhythmic medication. Outcome variables were mortality, cost, and length of stay (LOS). Multivariable models and propensity score matching were used. There were 2,657 neonates identified with a median gestational age of 37 weeks (interquartile range 34 to 39). Digoxin and propranolol were most commonly prescribed; digoxin use steadily decreased to 23% of antiarrhythmic medication administrations over the study period, whereas propranolol increased to 77%. Multivariable comparisons revealed that the odds of mortality for neonates on propranolol were 0.32 times those on digoxin (95% confidence interval 0.17 to 0.59; p <0.001); hospital costs were $16,549 lower for propranolol versus digoxin (95% confidence interval $5,502 to $27,596, p = 0.003). No difference was found for LOS. Propensity score matching and subset analyses of patients with only arrhythmia diagnostic codes confirmed mortality benefits for propranolol, although longer LOS was observed. In conclusion, propranolol use for the neonate with SVT is associated with lower in-hospital mortality and hospital costs compared with digoxin.

Nadolol for Treatment of Supraventricular Tachycardia in Infants and Young Children

Supraventricular tachycardia (SVT) is a common infant arrhythmia, for which beta-blockers are frequently chosen as therapy. Propranolol is a common choice though it is dosed every 6-8 h. We reviewed the clinical results of treating infant SVT with an extemporaneous preparation of nadolol. Retrospective cohort study of patients under 2 years old receiving nadolol for SVT at a single center. Patients were ascertained by patient and pharmacy databases. Twenty-eight infants received nadolol, of whom 25 had regular narrow complex tachycardia, 2 atrial flutter, and 1 focal atrial tachycardia. Patient age at initiation was a median 54 days (range 10-720). The final dose was 1 mg/kg/day in 22/28 patients (range 0.5-2). Once-daily dosing was used in 20 patients (71.4%); dosing was BID in 7, TID in 1. Among regular narrow complex tachycardia patients, 18/25 received nadolol monotherapy and 7 required additional agents; flecainide in 6, digoxin in 1. The median age of tachyarrhythmia onset was 18 days (range 1-180) with a median age of nadolol initiation of 30 days (range 11-390). Of the 20 regular narrow complex tachycardia patients initiated on nadolol monotherapy, 85% had no recurrences as of 1-year follow-up. Side effects were suspected in 3 of 28 (10.7%), including wheezing (n = 1, 3.5%), irritability and diarrhea (n = 1, 3.5%), and bradycardia (n = 1, 3.5%). Oral nadolol suspension was a successful treatment for SVT in 85% of patients with minimal adverse effects. Single daily dosing was used in the majority of patients.

Arrhythmias and Cardiac Bedside Monitoring in the Neonatal Intensive Care Unit

Cardiac physiology is unique in neonates and infants; there are several physiologic changes that occur in the first weeks of life. Important changes can be captured on the bedside monitor and provide vital data in a noninvasive way to providers. The importance of diligent observation cannot be overstated. Bedside monitoring has improved in the last decade, which has enhanced the ability to detect changes in heart rates and rhythms. The purpose here is to review cardiac physiology, describe those arrhythmias able to be observed on bedside monitors, and highlight heart rate changes that can be early signs of sepsis.

Variation in Antiarrhythmic Management of Infants Hospitalized with Supraventricular Tachycardia: A Multi-Institutional Analysis

Supraventricular tachycardia (SVT) is the most frequent form of symptomatic tachyarrhythmia in infants. The purposes of this study were to describe practice patterns of the management of infants hospitalized with SVT and factors associated with 30-day hospital readmission. This was a multi-institutional, retrospective review of the pediatric health information system database of SVT hospitalizations from 2003 to 2013. High-volume centers (HVC) were defined as those at the upper quartile of admissions. Infants with an ICD-9 code of paroxysmal SVT were included. Antiarrhythmics investigated included amiodarone, atenolol, digoxin, esmolol, flecainide, procainamide, propafenone, propranolol, and sotalol. Frequency of antiarrhythmic use based on center volume was the primary end point. Rate of 30-day SVT readmission was the secondary end point. Analysis of factors associated with readmission was assessed by Chi-square analysis and expressed as odds ratio and 95 % confidence interval. A total of 851 patients (60 % male, 44 % neonates) were hospitalized at 43 hospitals. Propranolol, digoxin, and amiodarone were the most frequently utilized antiarrhythmics. HVCs represented 12 hospitals comprising 494 (58 %) patients. Although HVCs were more likely to utilize propranolol (OR 2.5, CI 1.5-4.1), there was no significant difference in the 30-day readmission rate between patients treated at HVCs versus non-HVCs (p = 0.9). The majority of infants with SVT are treated with a small number of antiarrhythmic medications during index hospitalization. Although hospital-to-hospital variation in antiarrhythmic choice exists, there appears to be no difference in readmission. The remaining practice variation may be related to intrinsic patient characteristics.

Clinical research in neonates and infants: Challenges and perspectives

To date, up to 65% of drugs used in neonates and infants are off-label or unlicensed, as they were implemented in clinical care without the usual regulatory phases of pharmacological drug development. Pharmacotherapy in this age group is still mainly based on the individual clinical expertise of specialized pediatricians. Pharmacological trials involving neonates are indeed more difficult to perform: appropriate dosing is hampered by the rapid physiological changes occurring at this stage of development, and the selection of proper end-points and biomarkers is complicated by the limited knowledge of the pathophysiology of the specific diseases of infancy. Moreover, there are many ethical challenges in planning and conducting drug studies in pediatric patients (especially in newborns and infants). In the current review, we address some challenges and discuss possible perspectives to stimulate scientific and clinical pharmacological research in neonates and infants. We hereby aim to illustrate the add on value of the regulatory framework for model-based neonatal medicinal development currently used in Europe and the United States. We provide several examples of successful recent pharmacological trials performed in neonates and infants. In these examples, success was ensured by the implementation of specific pharmacokinetic assessments, thanks to accurate drug dosing achieved with a combination of dose validation, population pharmacokinetics and mathematical models of drug clearance and distribution; moreover, age-specific pharmacodynamics was considered via appropriate evaluations of drug efficacy with end-points adapted to the peculiar pathophysiology of diseases in this age group. These "pharmacological" challenges add to the ethical challenges that are always present in planning and conducting clinical studies in neonates and infants and support the opinion that clinical research in pediatrics should be evaluated by ad hoc ethical committees with specific expertise.

Serum digoxin concentrations and clinical signs and symptoms of digoxin toxicity in the paediatric population

BACKGROUND

Serum digoxin levels have limited utility for determining digoxin toxicity in adults. Paediatric data assessing the utility of monitoring serum digoxin concentration are scarce. We sought to determine whether serum digoxin concentrations are associated with signs and symptoms of digoxin toxicity in children.

METHODS

We carried out a retrospective review of patients 2 ng/ml).

RESULTS

There were 87 patients who met study criteria (male 46%, mean age 8.4 years). CHD was present in 67.8% and electrocardiograms were performed in 72.4% of the patients. The most common indication for digoxin toxicity was heart failure symptoms (61.5%). Toxic serum digoxin concentrations were present in 6.9% of patients (mean 2.6 ng/ml). Symptoms associated with digoxin toxicity occurred in 48.4%, with nausea/vomiting as the most common symptom (36.4%), followed by tachycardia (29.5%). Compared with those without toxic serum digoxin concentrations, significantly more patients with toxic serum digoxin concentrations were female (p=0.02). The presence of electrocardiogram abnormalities and/or signs and symptoms of digoxin toxicity was not significantly different between patients with and without serum digoxin concentrations (p>0.05).

CONCLUSION

Serum digoxin concentrations in children are not strongly associated with signs and symptoms of digoxin toxicity.

Wolff-Parkinson-White Syndrome in a Term Infant Presenting With Cardiopulmonary Arrest

BACKGROUND

Wolff-Parkinson-White syndrome is a congenital abnormality of the cardiac conduction system caused by the presence of an abnormal accessory electrical pathway between the atria and the ventricles. This can result in intermittent tachyarrhythmias such as supraventricular tachycardia. In rare occasions, sudden death may occur from atrial fibrillation with rapid ventricular conduction. Supraventricular tachycardia typically has a sudden onset and offset, classified as a paroxysmal arrhythmia. Because of the variable occurrence, Wolff-Parkinson-White syndrome may go undiagnosed in the immediate newborn period.

PURPOSE

To highlight arrhythmia as a possible cause of sudden decompensation in infants.

CASE FINDINGS/RESULTS

The clinical presentation of this infant is complex and a number of potential diagnoses were considered. Preexcitation on electrocardiogram resulted in the diagnosis of Wolff-Parkinson-White syndrome.

IMPLICATIONS FOR PRACTICE

Nurses caring for infants should be alert to tachycardia and irregularities of the heart rate, including those in the prenatal history, and should report them for evaluation. While all parents should be taught to watch for signs of illness, parents of infants with Wolff-Parkinson-White have additional learning needs, including recognizing early signs and symptoms of heart failure.

Association of Digoxin With Interstage Mortality: Results From the Pediatric Heart Network Single Ventricle Reconstruction Trial Public Use Dataset

BACKGROUND

Mortality for infants with single ventricle congenital heart disease remains as high as 8% to 12% during the interstage period, the time between discharge after the Norwood procedure and before the stage II palliation. The objective of our study was to determine the association between digoxin use and interstage mortality in these infants.

METHODS AND RESULTS

We conducted a retrospective cohort study using the Pediatric Heart Network Single Ventricle Reconstruction Trial public use dataset, which includes data on infants with single right ventricle congenital heart disease randomized to receive either a Blalock-Taussig shunt or right ventricle-to-pulmonary artery shunt during the Norwood procedure at 15 institutions in North America from 2005 to 2008. Parametric survival models were used to compare the risk of interstage mortality between those discharged to home on digoxin versus those discharged to home not on digoxin, adjusting for center volume, ascending aorta diameter, shunt type, and socioeconomic status. Of the 330 infants eligible for this study, 102 (31%) were discharged home on digoxin. Interstage mortality for those not on digoxin was 12.3%, compared to 2.9% among those on digoxin, with an adjusted hazard ratio of 3.5 (95% CI, 1.1-11.7; P=0.04). The number needed to treat to prevent 1 death was 11 patients. There were no differences in complications between the 2 groups during the interstage period.

CONCLUSIONS

Digoxin use in infants with single ventricle congenital heart disease is associated with significantly reduced interstage mortality.

Efficacy of digoxin in comparison with propranolol for treatment of infant supraventricular tachycardia: analysis of a large, national database

INTRODUCTION

Digoxin or propranolol are used as first-line enteral agents for treatment of infant supraventricular tachycardia. We used a large national database to determine whether enteral digoxin or propranolol was more efficacious as first-line infant supraventricular tachycardia therapy.

MATERIALS AND METHODS

The Pediatric Health Information System database was queried over 10 years for infants with supraventricular tachycardia initiated on enteral digoxin or propranolol monotherapy. Patients were excluded for Wolff-Parkinson-White, intravenous antiarrhythmics (other than adenosine), or death. Success was considered as discharge on the initiated monotherapy. Risk factors for successful monotherapy and risk factors for readmission for supraventricular tachycardia for patients discharged on monotherapy were determined.

RESULTS

A total of 374 patients (59.6% male) met the study criteria. Median length of stay was 7 days (interquartile range of 3-16 days). Patients had CHD (n=199, 53.2%) and underwent cardiac surgery (n=123, 32.9%), ICU admission (n=238, 63.6%), mechanical ventilation (n=146, 39.0%), and extracorporeal membrane oxygenation (n=3, 0.8%). Pharmacotherapy initiation was at median 37 days of life (interquartile range of 12-127 days) and 47.3% were initiated on digoxin. Success was similar between digoxin (73.1%) and propranolol (73.5%). Initial therapy with digoxin was not associated with success (odds ratio 1.01, 95% CI 0.64-1.61, p=0.93). Multivariable analysis demonstrated hospital length of stay (odds ratio 0.98, 95% CI 0.98-1.00) and involvement of a paediatric cardiologist (odds ratio 0.46, 95% CI 0.29-0.75) associated with monotherapy failure, and male gender (odds ratio 1.66, 95% CI 1.03-2.67) associated with monotherapy success. No variables were significant for readmission on multivariable analysis.

DISCUSSION

Digoxin or propranolol may be equally efficacious for inpatient treatment of infant supraventricular tachycardia.

Treatment of supraventricular tachycardia in infants: Analysis of a large multicenter database

OBJECTIVE

Supraventricular tachycardia (SVT) is the most common arrhythmia in infants. Infants are typically treated with antiarrhythmic medications, but there is a lack of evidence guiding management, thus exposing infants to risks of both inadequate therapy and medication adverse events. We used data from a large clinical database to better understand current practices in SVT management, safety of commonly used medications, and outcomes of hospitalized infants treated for SVT.

METHODS

This retrospective data analysis included all infants discharged from Pediatrix Medical Group neonatal intensive care units between 1998 and 2012 with a diagnosis of SVT who were treated with antiarrhythmic medications. We categorized infants by the presence of congenital heart disease other than patent ductus arteriosus. Medications were categorized as abortive, acute, or secondary prevention therapies. We used descriptive statistics to describe medication use, adverse events, and outcomes including SVT recurrence and mortality.

RESULTS

A total of 2848 infants with SVT were identified, of whom 367 (13%) had congenital heart disease. Overall, SVT in-hospital recurrence was high (13%), and almost one fifth of our cohort (18%) experienced an adverse event. Mortality was 2% in the overall cohort and 6% in the congenital heart disease group (p<0.001). Adenosine was the most commonly used abortive therapy, but there was significant practice variation in therapies used for acute treatment and secondary prevention of SVT.

CONCLUSION AND PRACTICE IMPLICATION

Significant variation in SVT treatment and suboptimal outcomes warrant future clinical trials to determine best practices in treating SVT in infants.

Efficacy and safety of high-dose propranolol for the management of infant supraventricular tachyarrhythmias

OBJECTIVE

To report our experience with high-dose propranolol monotherapy for prophylaxis and treatment of infant supraventricular arrhythmias (SAs).

STUDY DESIGN

Patients <1 year of age initiated on enteral propranolol as inpatients for management of SA were identified during a 10-year time period from the Texas Children's Hospital pharmacy database. Patients were included if they received propranolol monotherapy for SA. Propranolol therapy was considered successful when patients were initiated and discharged on monotherapy, without documented recurrence of arrhythmia or requiring additional antiarrhythmic medication. Patients discharged on propranolol were followed as outpatients until therapy was discontinued or a year from initiation, whichever came first.

RESULTS

A total of 287 patients met study criteria (59.2% male). Propranolol therapy was initiated at a median of 17 days of age (IQR 6-33 days) at a total daily dose of 3.6 ± 1.0 mg/kg/day. Propranolol was successful in controlling SA throughout the inpatient stay in 67.3% of patients. Only one patient experienced a clinically significant adverse event that required propranolol discontinuation. A multivariable logistic regression analysis identified the presence of congenital heart disease (OR 0.42, 95% CI 0.19-0.94, P = .04) and Wolff-Parkinson-White (OR 0.42, 95% CI 0.21-0.87, P = .01) as factors for nonsuccessful inpatient propranolol monotherapy. Of 190 patients discharged on propranolol monotherapy, 87.7% were recurrence free during follow-up.

CONCLUSIONS

High-dose propranolol is safe and reasonably successful in the treatment of infant SA. Inpatient control may be a predictor of continued outpatient efficacy.