Efficacy and proarrhythmia of oral sotalol in pediatric patients

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.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

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.

Tachyarrhythmias in Congenital Heart Diseases: From Ion Channels to Catheter Ablation

Major advances in pediatric cardiology in recent decades, especially surgical techniques, have resulted in an increasing number of patients with congenital heart disease (CHD) surviving to adulthood. This has generated new challenges, particularly with regards to the late onset of complex arrhythmias. Abnormal anatomy, surgical scarring, chronic hypoxemia, hemodynamic compromise, neuro-hormonal abnormalities, and genetic factors can all contribute to creating a unique substrate for arrhythmia development. This review attempts to synthesize the current state of knowledge spanning the spectrum from underlying mechanisms of arrhythmias in patients with congenital heart disease to current ablative strategies. We discuss existing knowledge gaps and highlight important areas for future research.

Role of amiodarone in the management of atrial arrhythmias in adult Fontan patients

BACKGROUND

Patients with Fontan circulation are known to be at high risk for developing atrial tachyarrhythmias (AAs). Our objective was to examine the efficacy and safety of amiodarone in the management of ATs in adult Fontan patients.

METHODS

Primary outcomes of this single-centre, retrospective study included freedom from AAs and incidence of adverse effects of amiodarone on Fontan patients. Heart failure (HF) events and composite outcomes of death from any cause, Fontan revision and heart transplantation were evaluated as secondary outcomes. Predictors of HF and discontinuing amiodarone were also evaluated.

RESULTS

A total of 61 patients (mean age 31.6±11.3 years, 40.9% female), who were treated with amiodarone in between 1995 and 2018, were included. AAs free survival at 1, 3 and 5 years were 76.2%, 56.9% and 30.6%, respectively. During a median follow-up of 50.5 months, 34 (55.7%) patients developed side effects, and 20 (32.8%) patients discontinued amiodarone due to side effects. Thyroid dysfunction was the most common side effect (n=26, 76.5%), amiodarone-induced thyrotoxicosis (AIT) (n=16, 27.1%) being most common thyroid dysfunction. Young age (age <28.5 years) was associated with discontinuing amiodarone (HR 5.50, 95% CI 1.19 to 25.4, p=0.029). AIT significantly increased risk of HF (HR 4.82, 95% CI 1.71 to 13.6, p=0.003).

CONCLUSIONS

Short-term efficacy of amiodarone in Fontan physiology is acceptable. However, long-term administration is associated with a reduction of efficacy and a significant prevalence of non-cardiac side effects. AIT is associated with exacerbation of HF. The judicious use of amiodarone administration should be considered in this population.

"Second line medications" for supraventricular arrhythmias in children: In-hospital efficacy and adverse events during treatment initiation of sotalol and flecainide

INTRODUCTION

Sotalol and flecainide are used as second line agents in children for the treatment of supraventricular arrhythmias (SA) refractory to anti-beta adrenergic antiarrhythmics or digoxin. Efficacy and adverse events in this cohort have not been well described. Here, we report our institutional experience of second line treatment initiation for SA in children.

METHODS AND RESULTS

Utilizing an institutional database, 247 patients initiated on sotalol and 81 patients initiated on flecainide were identified. Congenital heart disease (CHD) was present in 40% of patients. Arrhythmia-free discharge on single or dual agent therapy (in combination with other antiarrhythmics) was 87% for sotalol and 91% for flecainide. Neither age, sex, dosing, presence of CHD nor arrhythmia subtype were associated with alterations in in-hospital efficacy. Compared to baseline, QTc intervals in sotalol patients (436 [416-452 ms] vs. 415 [400-431 ms], p < .01) and QRS intervals in flecainide patients (75 [68-88 ms] vs. 62 [56-71 ms], p < .01) were prolonged. Dose reduction or discontinuation due to QRS prolongation occurred in 9% of patients on flecainide. QTc prolongation resulting in dose reduction/discontinuation of sotalol was encountered in 9 patients (4%) and death with documented torsade de pointes in 2 patients (1%), with 9 of 11 patients having underlying CHD.

CONCLUSION

In children requiring second line agents for treatment of SA, both sotalol and flecainide appear to be highly efficacious. Although predominantly safe in otherwise healthy patients, electrocardiogram changes can occur and children with underlying cardiac disease may have an increased risk of adverse events and rhythm-related side effects during initiation.

Safety and Efficacy of Landiolol Hydrochloride in Children with Tachyarrhythmia of Various Etiologies

The safety and efficacy of landiolol have not been fully elucidated in pediatric patients. This study aimed to clarify the safety and efficacy of landiolol in a pediatric cohort. We retrospectively assessed the clinical features of 21 pediatric patients who were administered landiolol at our hospital. We also investigated the rates of sinus rhythm conversion and heart rate response. The median patient age was 7 months (interquartile range 1-13 months). The etiology of tachyarrhythmia was junctional ectopic tachycardia in 10 patients (47.6%), atrial tachycardia in 10 patients (47.6%), and ventricular tachycardia in 1 patient (4.8%). Of the 21 children, 18 (85.7%) had congenital heart defects, including 14 (77.8%) in whom a landiolol infusion was performed perioperatively. The landiolol infusion was effective in 18 pediatric patients (85.7%), as measured by the conversion to sinus rhythm or a reduced heart rate. Atrial tachycardia in the perioperative period was terminated in all patients. Of 7 patients with tachyarrhythmias unrelated to the perioperative period, landiolol was effective in 5. No adverse effects were reported in any patient. Landiolol infusion is effective and safe in pediatric patients with tachyarrhythmia of various etiologies, especially those with atrial tachyarrhythmia during the perioperative period.

Intravenous Sotalol in the Young: Safe and Effective Treatment With Standardized Protocols

OBJECTIVES

This study assessed the safety and efficacy of novel and standardized protocols for the use of intravenous (IV) sotalol in pediatric patients.

BACKGROUND

Acute arrhythmia treatments in children remain limited. IV sotalol is a new option but pediatric experience is limited. There is no standardized protocol for rapid infusion during acute arrhythmias. This study assessed a single center's initial experience with IV sotalol in young patients, describing a protocol for rapid infusion for acute treatment, and reviewed the safety and efficacy of maintenance dosing.

METHODS

This is a retrospective study of all patients who received IV sotalol at Rady Children's Hospital. Demographics, arrhythmia, hemodynamics, and effects of IV sotalol were assessed.

RESULTS

Thirty-seven patients received IV sotalol from December 2015 to December 2018. Group 1 (n = 26) received sotalol for acute therapy and group 2 (n = 11) received a maintenance dose of sotalol after successful cardioversion with alternate therapies. The groups had similar demographics. Group 1 included patients with atrial flutter (n = 16), patients with supraventricular tachycardia (SVT) (n = 9), and patients with atrial ectopic tachycardia (AET) (n = 1). All 9 patients with SVT (100%) converted to sinus rhythm after failure to convert using adenosine. Median administration time was 15 min, the median dose was 30 mg/m², and mean time to cardioversion was 14 min. Group 2 median infusion time was 120 min, the median dose was 54 mg/m²/day, and all patients maintained sinus rhythm. No patients required cessation for adverse effects previously described for IV sotalol.

CONCLUSIONS

IV sotalol was safe and effective for acute and maintenance therapy in young patients. In acute patients, 30 mg/m² over 15 min converted most patients. IV sotalol adds a valuable option to IV therapies in the young.

Efficacy and adverse effects of sotalol in adults with congenital heart disease

INTRODUCTION

Adults with congenital heart disease (CHD) are predisposed to arrhythmias, which can often be refractory to medical therapy. Sotalol is an attractive alternative antiarrhythmic to amiodarone in this younger patient population, given the latter's toxicity profile, but it may have proarrhythmic effects. We therefore aimed to assess the efficacy and safety of sotalol in adults with CHD.

METHODS

We retrospectively assessed our adult CHD database for all patients ≥16 years old, with moderate to highly complex defects, who were prescribed sotalol between 2000 and 2017. Efficacy in treating the clinical arrhythmia was assessed as complete, partial or failure. Adverse effects, including proarrhythmia, were documented.

RESULTS

Sotalol was prescribed in 82 of 902 adult CHD patients reviewed (9%). The mean age at sotalol commencement was 31.8 ± 13.1 years, with a median time on sotalol of 2.8 years. The average prescribed dose was 122 ± 51 mg/daily. Sotalol was completely effective in 48% (n = 39), partially effective in 46% (n = 38) and failed to control the clinical arrhythmia in 6% (n = 5). Fifteen patients (18%) discontinued sotalol due to a side effect, most commonly fatigue or dyspnoea. No episodes of torsades de pointes or sudden cardiac death were observed. Significant bradycardia related to sotalol occurred in 13% (n = 11, with permanent pacing implemented in 4), and was associated with Fontan anatomy.

CONCLUSIONS

In moderate to highly complex adult CHD, sotalol was reasonably effective and safe in low doses. Side effects limiting treatment were typically non-life-threatening, with significant bradycardia related to sotalol more likely in Fontan patients.

Drug Therapy in Adult Congenital Heart Disease

Adults with congenital heart disease are at risk for atrial and ventricular arrhythmias that can lead to an increased morbidity as well as mortality. When catheter ablation is not an option or unsuccessful, antiarrhythmic drugs are the mainstay of treatment. There is limited data on the use of antiarrhythmics in this population. The purpose of this article is to discuss the practical aspects of the use of antiarrhythmics in adults with congenital heart disease. Several tables have been provided to provide clinicians a reference for daily use.

Predictors of Pharmacological Therapy of Ectopic Atrial Tachycardia in Children

Ectopic atrial tachycardia (EAT) is a relatively common type of supraventricular tachycardia in the pediatric population, and it can be resistant to antiarrhythmic drugs and lead to tachycardia-induced cardiomyopathy (TIC) if not properly managed. The purpose of this study was to determine the predictors of the response to pharmacological therapy in children with EAT. From January 2009 to April 2014, 115 children were admitted to our hospital with a diagnosis of EAT and placed on antiarrhythmic drugs. We examined the clinical history, response to therapy, and follow-up of the children. The incidence of TIC secondary to EAT was 22.6% (n = 26) in children. Incessant EAT accounted for 44.3% of all patients. Control of EAT with antiarrhythmic therapy was achieved in 73.9% (n = 85) of the children. The combination of sotalol and propafenone performed well in controlling EAT in children [complete control in 35 (49.3%) of 71]. The mean time of conversion to sinus rhythm was 24 days, and the mean duration of therapy was 11 months in children with resolution. Multivariate predictors of the control of EAT were age at presentation (OR 0.289, P = 0.038) and tachycardia type (OR 0.276, P = 0.006). TIC occurs in 22.6% of children with EAT. Incessant EAT is more frequently complicated by TIC. Independent factors associated with a good response to pharmacological therapy include a younger age at presentation and non-incessant tachycardia in children with EAT.

Pediatric Dosing of Intravenous Sotalol Based on Body Surface Area in Patients with Arrhythmia

In a recently published study, we evaluated the efficacy and safety of intravenous sotalol in pediatric patients with incessant tachyarrhythmias and we have found that intravenous sotalol is effective and safe. Our dosing regimen was based on the body weight of the patients. In the US, the recommendation for intravenous sotalol dosing in pediatric patients is based on body surface area (BSA) while taking into consideration the patients' age. The purpose of this paper is to show the correspondence of a body weight-based dosing regimen when expressed for BSA as mg/m². We evaluated the similarity of a body weight-based dose to that calculated based on BSA using the US labeling recommendations. Of the 83 patients, 5 were newborns (age: 0-30 days), 39 infants and toddlers (age: 1-24 month), 26 young children (age: >2-6 years), 11 older children (age: 6-12 years), and 2 adolescents (age: 14 years). Each received a loading dose of 1 mg/kg intravenous sotalol administered over 10 min followed by a maintenance dose of 4.5 mg/kg/day. There was a close correlation between the sotalol loading doses calculated based on body weight and BSA across the entire age range (r = 0.977, p < 0.001). In most of the age groups, the body weight-based loading doses were lower or equal to the BSA-based doses. Only in the adolescents were the body weight-based doses higher. The maintenance doses given in our study were significantly higher than the BSA-based dose in newborns: 75 ± 6 versus 53 ± 8 mg/m², p < 0.05; infants/toddlers: 88 ± 14 versus 77 ± 7 mg/m², p < 0.001; younger children: 113 ± 12 versus 85 mg/m², p < 0.001; older children: 123 ± 16 versus 85 mg/m², p < 0.01; and adolescents 157 ± 30 versus 85.5 mg/m². Despite the rapid administration of the loading dose and the increased maintenance doses, our body weight-based dosing regimen was safe. Only one newborn had significant adverse event (AV block) that resolved spontaneously after discontinuation of the infusion.

[Non-invasive treatment of tachycardias during childhood]

In principle tachycardias during childhood do not differ from those in adulthood but they present with a significant age-dependency. Additionally the clinical presentation has a broad spectrum related to the different ages, from the neonatal period until adolescence. If congenital heart disease is present the hemodynamic compromise may be accentuated. This paper describes the diagnostic and therapeutic approaches to pediatric tachycardias with focus upon the age dependent aspects and the presense of congenital heart disease, either native or postoperative.

Sotalol as first-line treatment for fetal tachycardia and neonatal follow-up

OBJECTIVES

In fetal tachycardia, pharmacological therapy with digoxin, flecainide and sotalol has been reported to be effective. In a recent retrospective multicenter study, sotalol was considered to be less effective than the other drugs in treatment of fetal supraventricular tachycardia (SVT). The aim of this study was to re-evaluate the efficacy and safety of maternally administered sotalol in the treatment of fetal tachycardia.

METHODS

This was a retrospective review of the records of 30 consecutive fetuses with tachycardia documented on M-mode echocardiography between January 2004 and December 2010 at Wilhelmina Children's Hospital, a tertiary referral university hospital. Patients were subdivided into those diagnosed with supraventricular tachycardia and those with atrial flutter (AF) and presence of hydrops was noted. Other variables investigated included QTc interval measured on maternal electrocardiogram before and after initiation of antiarrhythmic therapy, fetal heart rhythm and heart rate pre- and postnatally, oral maternal drug therapy used, time to conversion to sinus rhythm (SR), percentage of fetuses converted following transplacental treatment, maternal adverse effects, presence or absence of tachycardia as noted on postnatal ECG, postnatal therapy or prophylaxis and neonatal outcome. Findings are discussed with reference to the literature.

RESULTS

A total of 28 patients (18 with SVT, 10 with AF) were treated with sotalol as first-line therapy. Fetal hydrops was present in six patients (five with SVT, one with AF). All hydropic patients converted antenatally to SR (67% with sotalol as a single-drug therapy, 33% after addition of flecainide). Of the non-hydropic patients, 91% converted to SR (90% with sotalol only, 10% after addition of flecainide or digoxin). In 9% (with AF) rate control was achieved. There was no mortality. No serious drug-related adverse events were observed. Postnatally, rhythm disturbances were detected in 10 patients, two of whom still had AF. In eight, SVT was observed within 3 weeks postnatally, and in five of these within 72 hours.

CONCLUSIONS

Sotalol can be recommended as the drug of first choice for treatment of fetal AF and has been shown to be an effective and safe first-line treatment option for SVT, at least in the absence of hydrops. Postnatal maintenance therapy after successful prenatal therapy is not necessarily indicated, as the risk of recurrence is low beyond 72 hours of age.

The Study of Antiarrhythmic Medications in Infancy (SAMIS)

Background—

Supraventricular tachycardia (SVT) is one of the most common conditions requiring emergent cardiac care in children, yet its management has never been subjected to a randomized controlled clinical trial. The purpose of this study was to compare the efficacy and safety of the 2 most commonly used medications for antiarrhythmic prophylaxis of SVT in infants: digoxin and propranolol.

Methods and Results—

This was a randomized, double-blind, multicenter study of infants <4 months with SVT (atrioventricular reciprocating tachycardia or atrioventricular nodal reentrant tachycardia), excluding Wolff-Parkinson-White, comparing digoxin with propranolol. The primary end point was recurrence of SVT requiring medical intervention. Time to recurrence and adverse events were secondary outcomes. Sixty-one patients completed the study, 27 randomized to digoxin and 34 to propranolol. SVT recurred in 19% of patients on digoxin and 31% of patients on propranolol ( P =0.25). No first recurrence occurred after 110 days of treatment. The 6-month recurrence-free status was 79% for patients on digoxin and 67% for patients on propranolol ( P =0.34), and there were no first recurrences in either group between 6 and 12 months. There were no deaths and no serious adverse events related to study medication.

Conclusions—

There was no difference in SVT recurrence in infants treated with digoxin versus propranolol. The current standard practice may be treating infants longer than required and indicates the need for a placebo-controlled trial.

Clinical Trial Registration Information—

http://clinicaltrials.gov ; NCT-00390546.

Extracorporeal membrane oxygenation support for intractable primary arrhythmias and complete congenital heart block in newborns and infants: short-term and medium-term outcomes

OBJECTIVES

To describe the experience with extracorporeal membrane oxygenation support for intractable primary arrhythmias in newborns and infants.

DESIGN

Retrospective study.

SETTING

A tertiary care pediatric hospital.

PATIENTS

Patients younger than 1 yr supported with extracorporeal membrane oxygenation for primary cardiac arrhythmias were identified from the institutional extracorporeal membrane oxygenation registry.

INTERVENTIONS

Extracorporeal membrane oxygenation support.

MEASUREMENTS AND MAIN RESULTS

Clinical characteristics and outcomes were investigated for patients with primary cardiac arrhythmia supported with extracorporeal membrane oxygenation. Outcomes investigated were time from initiation of extracorporeal membrane oxygenation support to arrhythmia control, duration of extracorporeal membrane oxygenation support, and results of interventions performed while supported with extracorporeal membrane oxygenation. We summarized the independent categorical and continuous variables using frequencies, percentages, and medians and ranges, respectively. Extracorporeal membrane oxygenation support was used in nine patients for rescue therapy for primary tachyarrhythmia and bradycardia. The primary arrhythmias were: focal atrial tachycardia (n = 2); reentrant supraventricular tachycardia (n = 3); junctional ectopic tachycardia (n = 2); and congenital complete atrioventricular block (n = 2) patients. Seven patients presented with severe hemodynamic compromise, with six patients requiring extracorporeal cardiopulmonary resuscitation. All patients required extracorporeal membrane oxygenation within 24 hrs of initial presentation. Balloon atrial septostomy was performed in three patients and ablation was performed in two patients. Sinus rhythm was achieved in all reentrant supraventricular tachycardia and rate control was established in both patients with focal atrial tachycardia and in one patient with junctional ectopic tachycardia while using extracorporeal membrane oxygenation support. All patients survived to hospital discharge, and median follow-up for the cohort was 5 yrs. There was one late death; all survivors had good overall and neurologic outcomes.

CONCLUSIONS

The requirement of extracorporeal membrane oxygenation support in newborns and infants with intractable arrhythmia is rare. Extracorporeal membrane oxygenation support does potentially carry morbidity; however, to prevent arrhythmia-related mortality, extracorporeal membrane oxygenation support and/or extracorporeal cardiopulmonary resuscitation should be considered in the management of hemodynamically unstable primary arrhythmias as an emergent lifesaving procedure.

Supraventricular tachycardia in neonates: antiarrhythmic drug choice dilemma

Supraventricular tachycardia (SVT), being atrioventricular re-entry the underlying mechanism, is the most frequent tachyarrhythmia requiring a medical treatment in infants with no cardiac disease. The acute treatment of a single episode of SVT has generally an excellent prognosis. An antiarrhythmic prophylaxis of SVT recurrences is usually recommended during the first year of life. Although many efficient drugs are available for the SVT treatment, a careful risk-benefit analysis of each single case should suggest the correct drug choice.

Supraventricular tachycardia in neonates: antiarrhythmic drug choice dilemma

Supraventricular tachycardia (SVT), being atrioventricular reentry the underlying mechanism, is the most frequently tachyarrhythmia requiring a medical treatment in infants with no cardiac disease. The acute treatment of a single episode of SVT has generally an excellent prognosis. An antiarrhythmic prophylaxis of SVT recurrences is usually recommended during the first year of life. Although many efficient drugs are available for the SVT treatment, a careful risk-benefit analysis of each single case should suggest the correct drug choice.

Intravenous amiodarone used alone or in combination with digoxin for life-threatening supraventricular tachyarrhythmia in neonates and small infants

OBJECTIVES

The purpose of this study was to report the efficacy of intravenous amiodarone alone or in combination with digoxin in neonates and small infants with life-threatening supraventricular tachyarrhythmia (SVT).

METHODS

We retrospectively analyzed 9 neonates and small infants with life-threatening or resistant SVT who were treated with intravenous amiodarone alone or in combination with digoxin.

RESULTS

This report consists of 8 patients with reentrant SVT and 1 with atrial flutter. On admission, 7 patients had a congestive heart failure and 3 of whom had cardiovascular collapse. Intravenous rapid bolus of adenosine caused a sustained sinus rhythm in 4 patients. These patients were given digoxin initially, but recurrence of persistent tachyarrhythmia necessitated the use of intravenous amiodarone in all these patients. Amiodarone was given initially to the other 4 patients in whom adenosine caused only temporary conversion to the sinus rhythm. It was effective in 2 patients. In the other 2, digoxin was added to therapy for tachycardia control. Amiodarone alone or in combination with digoxin effectively controlled reentrant SVT in all patients. This combined treatment caused ventricular rate control in patient with atrial flutter, and conversion to the stable sinus rhythm was achieved at approximately 8 months.

CONCLUSIONS

Intravenous amiodarone alone or in combination with digoxin was found to be safe and effective in controlling refractory and life-threatening SVT in neonates and small infants.

Atrial tachycardias in young adults and adolescents with congenital heart disease: conversion using single dose oral sotalol

Atrial tachyarrhythmias are a chronic long-term hazard in patients with congenital heart disease (CHD). These arrhythmias contribute to ventricular dysfunction, heart failure can contribute to sudden death. We performed a prospective study of oral sotalol for the conversion of atrial tachyarrhythmias in adults and adolescents with congenital heart disease and stable hemodynamics.

METHODS

Patients were admitted and given oral sotalol in an inpatient, monitored setting. The initial dose was targeted at 2 mg/kg. Antiarrhythmic drugs other than digoxin were stopped.

RESULTS

Nineteen patients were enrolled. The average patient age was 20 years (12-39). Four had atrial ectopic tachycardia (AET) and 15 had atrial reentry tachycardia (IART). Nine had Fontan physiology. Permanent pacing therapies had failed to restore sinus or paced rhythm consistently in 6 patients. Overall 16 of 19 atrial tachyarrhythmias (84%) converted with single dose oral sotalol. AET converted to sinus or paced rhythm in 3/4 patients and IART in 13/15 patients. The average times to conversion were 98 and 145 min, respectively. Two patients required pacemakers due to sinus bradycardia. One patient had a lethal thromboembolic event 2 days after conversion.

CONCLUSIONS

Oral sotalol offers an effective alternative to direct current cardioversion in adults and adolescents with CHD and hemodynamically stable atrial tachyarrhythmias. Conversion with sotalol at ~2 mg/kg generally occurred within 2 h. Vigilance for thromboembolism must be maintained as well as caution for those with bradycardia without pacemakers in this patient population. There are theoretical and practical advantages of sotalol over cardioversion.

Impact of curative ablation on pharmacologic management in children with reentrant supraventricular tachycardias

BACKGROUND

The introduction of radiofrequency catheter ablation as a curative treatment option has led to a much better outlook for children with recurrent supraventricular reentrant tachycardias (SVT). This study sought to evaluate the impact of ablation on pharmacologic treatment of SVT.

METHODS

Two time periods were retrospectively compared with regard to number of episodes of SVT in different age groups, number of acute drug conversions of SVT, chronic antiarrhythmic drug treatments prescribed: in the first period (1989-1994) management of SVT was exclusively pharmacological whereas during the second period (1995-2000) ablation was an option for patients aged 5 years or older.

RESULTS

The study included 88 pediatric patients with recurrent SVT, 40 in the first period, 48 in the latter. Of these, 16 children (all >5 years of age) had an ablation procedure during the second time period. In patients aged >5 years, the number of documented SVT fell from a mean of 3.7/patient to two episodes. The number of acute drug conversions of SVT decreased from a mean of 1.1/patient to 0.2 (p<0.05) during the second period. In the group of children aged >5 years chronic antiarrhythmic treatment was given during a mean of 15 months/patient in period one compared to 4.6 months (p<0.05) in the second period.

CONCLUSION

In the current era with increasing use of ablation as first-line treatment in older children with recurrent SVT, acute as well as chronic pharmacologic intervention for SVT has become significantly less frequent.

Establishment of an Enzyme-Linked Immunosorbent Assay for Measurement of Sotalol

We have established an enzyme-linked immunosorbent assay suitable for routine monitoring of serum levels of sotalol. Anti-sotalol antibody was obtained by immunizing rabbits with sotalol conjugated with bovine serum albumin using the N-succinimidyl ester method. An enzyme marker was similarly prepared by coupling sotalol with beta-D-galactosidase. The detection limit of sotalol by the enzyme-linked immunosorbent assay was approximately 32 ng/ml with 50-microl samples. This assay was specific for sotalol because of very slight cross-reactivity with 4-(methanesulfonylamino)benzonitrile (1.6%), but none with D,L-isoproterenol. Using this assay, drug levels were easily measured in the serum of rabbits after oral administration of sotalol at a single dose of 3 mg/kg. The enzyme-linked immunosorbent assay should be a valuable tool in therapeutic drug monitoring and pharmacokinetic studies of sotalol.

Antiarrhythmic drugs: new agents and evolving concepts

Properties of several new antiarrhythmic drugs are summarised in this review article. Recent concepts concerning their safety and efficacy of antiarrhythmics are discussed. A brief perspective on possible future strategies for pharmacotherapy of arrhythmias is provided.

Sotalol in treatment of pediatric cardiac arrhythmias

BACKGROUND

There is limited experience on sotalol use in the management of childhood arrhythmias. This study reviews the results of our experience with oral sotalol for treatment and prevention of tachyarrhythmias in children.

METHODS

The records of 62 patients (27 female, 35 male, mean age: 8.5+/-5.3 years) treated with sotalol for supraventricular or ventricular arrhythmias from 1994 to 1999 at our institution were reviewed. Demographic, clinical, echocardiographic, electrocardiographic (ECG), ambulatory ECG and electrophysiologic variables were collected.

RESULTS

Forty-two (63.6%) patients had re-entrant supraventricular tachycardia, eight patients (12.9%) had atrial tachycardia, one patient (1.6%) had junctional ectopic tachycardia, four patients (6.5%) had ventricular tachycardia, and seven patients (11.3%) had complex ventricular arrhythmias, as evidenced by surface or ambulatory ECG records; or revealed during the electrophysiological study. The mean sotalol dose was 3.9+/-1.2 mg/kg per day. In 15.5+/-13.9 months of sotalol use 50% (n=31) had complete relief of symptoms and/or arrhythmia and 29% (n=18) had partial relief. Sotalol was ineffective in 20% (n=13). Sotalol was more effective in re-entrant type supraventricular tachycardias (P=0.012). Sotalol was the first choice in 35.5% of patients. The sotalol therapy was initiated in inpatient settings in 40.3% (25 patients). Complications due to sotalol were seen in six patients (five patients developed bradycardia/pauses, and one patient had torsades de pointes) for which the sotalol dose was modified. In patients with sick sinus syndrome, a pacemaker was implanted and in another patient sotalol was stopped.

CONCLUSION

Sotalol, being an effective and safe drug particularly in children, is a good therapeutic alternative for the preventive treatment of childhood tachyarrhythmias.