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

Wolff-Parkinson-White Syndrome in the Preterm Neonate

Wolff-Parkinson-White (WPW) syndrome is a rare cardiac condition arising from abnormal embryologic development of the annulus fibrosus in combination with the cardiac conduction system. The abnormality results in the development of accessory pathways and preexcitation changes which can provoke episodes of tachyarrhythmias. The most common presentation of WPW syndrome is supraventricular tachycardia. Beyond customary abortive therapy, chronic management strategies vary based upon timing and clinical severity of the initial disease presentation. Prompt diagnosis and rate control have a dramatic impact on the outcomes of morbidity and mortality. The purpose of this article is to present a case study of a preterm infant who manifested with WPW syndrome. Additionally, the article will explore the pathophysiology of WPW syndrome and the timing and presentation of common clinical manifestations of the disease, along with current diagnostic and treatment strategies to achieve optimal patient outcomes in the neonatal population.

Revisiting the mutagenicity and genotoxicity of N-nitroso propranolol in bacterial and human in vitro assays

Propranolol is a widely used β-blocker that can generate a nitrosated derivative, N-nitroso propranolol (NNP). NNP has been reported to be negative in the bacterial reverse mutation test (the Ames test) but genotoxic in other in vitro assays. In the current study, we systematically examined the in vitro mutagenicity and genotoxicity of NNP using several modifications of the Ames test known to affect the mutagenicity of nitrosamines, as well as a battery of genotoxicity tests using human cells. We found that NNP induced concentration-dependent mutations in the Ames test, both in two tester strains that detect base pair substitutions, TA1535 and TA100, as well as in the TA98 frameshift-detector strain. Although positive results were seen with rat liver S9, the hamster liver S9 fraction was more effective in bio-transforming NNP into a reactive mutagen. NNP also induced micronuclei and gene mutations in human lymphoblastoid TK6 cells in the presence of hamster liver S9. Using a panel of TK6 cell lines that each expresses a different human cytochrome P450 (CYP), CYP2C19 was identified as the most active enzyme in the bioactivation of NNP to a genotoxicant among those tested. NNP also induced concentration-dependent DNA strand breakage in metabolically competent 2-dimensional (2D) and 3D cultures of human HepaRG cells. This study indicates that NNP is genotoxic in a variety of bacterial and mammalian systems. Thus, NNP is a mutagenic and genotoxic nitrosamine and a potential human carcinogen.

Assessing the Risk of Hypoglycemia Secondary to Propranolol Therapy for the Treatment of Supraventricular Tachycardia in Infants

Supraventricular tachycardia (SVT) is the most common arrhythmia among infants. Prevention of SVT is frequently managed through propranolol therapy. Hypoglycemia is a known adverse effect of propranolol therapy, but little research has been done on the incidence and risk of hypoglycemia in treatment of SVT in infants with propranolol. This study attempts to offer insight into the risk of hypoglycemia associated with propranolol therapy when treating infantile SVT to help inform future glucose screening guidelines. We conducted a retrospective chart review of infants treated with propranolol in our hospital system. Inclusion criteria were infants < 1 year of age who received propranolol for the treatment of SVT. A total of 63 patients were identified. Data was collected on sex, age, race, diagnosis, gestational age, nutrition source (Total Parenteral Nutrition (TPN) vs oral), weight (kg), weight for length (kg/cm), propranolol dose (mg/kg/day), comorbidities, and whether or not a hypoglycemic event was identified (< 60 mg/dL). Hypoglycemic events were identified in 9/63 (14.3%) patients. Of the patients with hypoglycemic events, 9/9 (88.9%) had comorbid conditions. Patients with hypoglycemic events had significantly lower weight and propranolol dose than those without hypoglycemic events. Weight for length also tended to increase risk for hypoglycemic events. The high incidence of comorbid conditions in the patients who had hypoglycemic events suggests that hypoglycemic monitoring may only be necessary in patients with conditions predisposing to hypoglycemia.

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.

Propranolol versus Other Selected Drugs in the Treatment of Various Types of Anxiety or Stress, with Particular Reference to Stage Fright and Post-Traumatic Stress Disorder

Propranolol, a non-cardioselective β1,2 blocker, is most commonly recognised for its application in the therapy of various cardiovascular conditions, such as hypertension, coronary artery disease, and tachyarrhythmias. However, due to its ability to cross the blood-brain barrier and affinity towards multiple macromolecules, not only adrenoreceptors, it has also found application in other fields. For example, it is one of the very few medications successfully applied in the treatment of stage fright. This review focuses on the application of propranolol in the treatment of various types of anxiety and stress, with particular reference to stage fright and post-traumatic stress disorder (PTSD). Both mechanisms of action as well as comparison with other therapies are presented. As those indications for propranolol are, in most countries, considered off-label, this review aims to gather information that can be useful while making a decision about the choice of propranolol as a drug in the treatment of those mental conditions.

Blockade of beta-adrenergic receptors reduces cancer growth and enhances the response to anti-CTLA4 therapy by modulating the tumor microenvironment

The development of immune checkpoint inhibitors (ICI) marks an important breakthrough of cancer therapies in the past years. However, only a limited fraction of patients benefit from such treatments, prompting the search for immune modulating agents that can improve the therapeutic efficacy. The nonselective beta blocker, propranolol, which for decades has been prescribed for the treatment of cardiovascular conditions, has recently been used successfully to treat metastatic angiosarcoma. These results have led to an orphan drug designation by the European Medicines Agency for the treatment of soft tissue sarcomas. The anti-tumor effects of propranolol are suggested to involve the reduction of cancer cell proliferation as well as angiogenesis. Here, we show that oral administration of propranolol delays tumor progression of MCA205 fibrosarcoma model and MC38 colon cancer model and increases the survival rate of tumor bearing mice. Propranolol works by reducing tumor angiogenesis and facilitating an anti-tumoral microenvironment with increased T cell infiltration and reduced infiltration of myeloid-derived suppressor cells (MDSCs). Using T cell deficient mice, we demonstrate that the full anti-tumor effect of propranolol requires the presence of T cells. Flow cytometry-based analysis and RNA sequencing of FACS-sorted cells show that propranolol treatment leads to an upregulation of PD-L1 on tumor associated macrophages (TAMs) and changes in their chemokine expression profile. Lastly, we observe that the co-administration of propranolol significantly enhances the efficacy of anti-CTLA4 therapy. Our results identify propranolol as an immune modulating agent, which can improve immune checkpoint inhibitor therapies in soft tissue sarcoma patients and potentially in other cancers.

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.

Pulp chamber opening alternative in pulpectomies in a child with Wolff-Parkinson-White syndrome. A case report

BACKGROUND

Wolff-Parkinson-White syndrome is a congenital abnormality of the heart. Patients with this syndrome and multiple dental caries with pulp exposure may require comprehensive dental treatment under general anesthesia. Pulpectomy is performed in primary teeth with pulp expose. This treatment in anterior teeth requires palatal access and the majority there is no good visibility, requiring more time to perform. Therefore, this case aimed to demonstrate a pulp chamber opening alternative in pulpectomies in a child with Wolff-Parkinson-White syndrome.

CASE PRESENTATION

A 3-year-old female patient with Wolff-Parkinson-White syndrome and multiple dental caries with reversible pulpitis in anterior upper teeth. The dental treatment was performed under general anesthesia. Due to abundant hemorrhage in anterior upper teeth, pulpectomies were performed, which pulp chamber openings were modified by labial and the treatment itself was completed. After, these teeth were rehabilitated with direct restorative veneers using light-curing composite resin. The follow-up at 12 months showed an absence of evidence clinic and radiographic.

CONCLUSION

This case demonstrated the pulp chamber opening performed by labial in pulpectomy is an effective and viable alternative to reduce operative time and improve visibility in pulpotomies in a child with Wolff-Parkinson-White syndrome.

[Radiofrequency catheter ablation in pediatric population: clinical, electrophysiological and therapeutic characteristics in a Peruvian pediatric hospital]

Objective

This study aims to describe the clinical, electrophysiological and therapeutic characteristics of pediatric patients with supraventricular tachycardia undergoing radiofrequency ablation.

Materials and methods

Observational, descriptive, retrospective study of children admitted for supraventricular tachycardia treatment at the Instituto Nacional de Salud del Niño during 2018 to 2021.

Results

Data from 62 procedures were collected, corresponding to 59 patients (mean age: 9.91 years, 61% male), 23% of procedures were performed in patients under 15kg, and two were in patients under 5kg. 63% of patients had a structurally normal heart, while 37% had some type of congenital heart disease, the most common being Ebstein's anomaly. The most widely used group of drugs were beta-blockers, mainly propranolol. Among the arrhythmias treated, 21.7% had preexcitation Syndrome, 33.3% had at least one hidden accessory pathway, 5% corresponded to permanent reciprocating junctional tachycardia, 5% intranodal tachycardia, 11.7% atrial tachycardia, 10 % atrial flutter, 5% had other types of tachycardia and in 5 cases no tachycardia was induced. Of the total procedures, 76% corresponded to electrophysiological study and ablation, four patients recurred.

Conclusions

The most common supraventricular tachycardia substrate in children was the presence of some accessory pathway. Radiofrequency catheter ablation could be applied in children with a high success rate and a low complication rate.

Design and rationale of a clinical trial to increase cardiomyocyte division in infants with tetralogy of Fallot

BACKGROUND

Patients with Tetralogy of Fallot with pulmonary stenosis (ToF/PS), the most common form of cyanotic congenital heart disease (CHD), develop adverse right ventricular (RV) remodeling, leading to late heart failure and arrhythmia. We recently demonstrated that overactive β-adrenergic receptor signaling inhibits cardiomyocyte division in ToF/PS infants, providing a conceptual basis for the hypothesis that treatment with the β-adrenergic receptor blocker, propranolol, early in life would increase cardiomyocyte division. No data are available in ToF/PS infants on the efficacy of propranolol as a possible novel therapeutic option to increase cardiomyocyte division and potentially reduce adverse RV remodeling.

METHODS

Using a randomized, double-blind, placebo-controlled trial, we will evaluate the effect of propranolol administration on reactivating cardiomyocyte proliferation to prevent adverse RV remodeling in 40 infants with ToF/PS. Propranolol administration (1 mg/kg po QID) will begin at 1 month of age and last until surgical repair. The primary endpoint is cardiomyocyte division, quantified after ¹⁵N-thymidine administration with Multi-isotope Imaging Mass Spectrometry (MIMS) analysis of resected myocardial specimens. The secondary endpoints are changes in RV myocardial and cardiomyocyte hypertrophy.

CONCLUSION

This trial will be the first study in humans to assess whether cardiomyocyte proliferation can be pharmacologically increased. If successful, the results could introduce a paradigm shift in the management of patients with ToF/PS from a purely surgical approach, to synergistic medical and surgical management. It will provide the basis for future multi-center randomized controlled trials of propranolol administration in infants with ToF/PS and other types of CHD with RV hypertension.

CLINICAL TRIAL REGISTRATION

The trial protocol was registered at clinicaltrials.gov (NCT04713657).

The Pathophysiology, Diagnosis, and Management of Wolff-Parkinson-White Syndrome in the Neonate

BACKGROUND

Wolff-Parkinson-White (WPW) is a congenital defect of the cardiac conduction system (CCS), with proliferation of extra embryologic conduction pathways and rapid conduction of electrical impulses. The estimated neonatal incidence of 0.1% to 0.2% may be misrepresented secondary to missed or misdiagnosis. Undiagnosed WPW can result in sudden cardiac death.

PURPOSE

To discuss the pathogenesis, manifestations, diagnosis, management, and lifespan implications of WPW in the prenatal and postnatal periods.

METHODS/SEARCH STRATEGY

A literature review was conducted using PubMed, CINAHL, and Google Scholar (2013-2019). Search terms included (newborn OR infant), wolff parkinson white, pathogenesis, management, and ventricular preexcitation. After removal of duplicates, 267 references were identified, abstracts reviewed, and 30 publications fully evaluated.

FINDINGS/RESULTS

Separation of the heart chambers begins around 7 weeks' gestation with formation of the annulus fibrosis complete after term. The unknown external environmental influence on the development of the preterm infant's CCS places neonates at risk for persistent atrioventricular reentrant tachycardia with WPW development. Ensuring an appropriate diagnosis is crucial, as an incorrect diagnosis could mean death.

IMPLICATIONS FOR PRACTICE

Due to the rarity of WPW, any fetal or neonatal supraventricular tachycardia requires further evaluation with an electrocardiogram and involvement of an experienced cardiologist for diagnosis. One episode of supraventricular tachycardia warrants evaluation for WPW, as recurring episodes may result in irreversible damage.

IMPLICATIONS FOR RESEARCH

The recommendations for treatment of WPW in the prenatal and immediate postnatal periods are based heavily on standards of care for the adult population. A paucity of evidenced-based literature exists and future research is crucial to understand the true incidence, physiologic effects, and lifespan implications of WPW on neonates.

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.

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.

Sustained tachyarrhythmia in children younger than 1 year of age: Six year single-center experience

BACKGROUND

The aim of this study was to evaluate the results of non-operational sustained tachyarrhythmia in patients <1 year of age at the present center.

METHODS

Between November 2010 and November 2016, the demographic characteristics, type and localization of the tachyarrhythmia, echocardiographic findings, and medical and/or ablation therapy for patients <1 year of age with sustained tachyarrhythmia were evaluated.

RESULTS

Of 99 patients, 91 had sustained supraventricular tachycardia, and eight had sustained ventricular tachycardia. The median age was 30 days (range, 1-350 days), and the median weight was 4.2 kg (range, 2-13 kg). The common symptoms were palpitation and restlessness (n = 49, 49.5%), or the tachycardia was detected during routine inspection (n = 25, 25.3%) or fetal echocardiography (n = 11, 11.1%). Nineteen individuals (19%) had left ventricular (LV) dysfunction on first echocardiography. Twenty individuals had congenital heart disease. Common diagnoses were Wolff-Parkinson-White syndrome (n = 27), focal atrial tachycardia (n = 10), permanent junctional reciprocating tachycardia(n = 6), and atrial flutter (n = 6). Seventeen patients underwent medical therapy combined with cardioversion. The most commonly used abortive and acute therapy agents were adenosine, esmolol, and amiodarone. The most common combination therapy was propranolol and amiodarone, followed by a propranolol and propafenone combination. Nine individuals were treated with catheter ablation due to either resistance to medical therapy or LV dysfunction.

CONCLUSIONS

Tachyarrhythmias in children <1 year of age are mostly caused by accessory pathways and require multidrug therapy. Catheter ablation is an effective alternative therapy in the case of resistance to medical therapy and/or LV dysfunction.

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.

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.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Antiarrhythmics

OBJECTIVE

Arrhythmias are a common occurrence in critically ill pediatric patients. Pharmacotherapy is a usual modality for treatment and prevention of arrhythmias in this patient population. This review will highlight particular arrhythmias in the pediatric critical care population and discuss salient points of pharmacotherapy of these arrhythmias. The mechanisms of action for the various agents, potential adverse events, place in therapy, and evidence for their use will be summarized.

DATA SOURCES

The literature was searched for articles related to the topic. Expertise of the authors and a consensus of the editors were additional sources of data in the article.

DATA SYNTHESIS

The author team synthesized the current pharmacology and recommendations and present them in this review. Tables were generated to summarize the state of the art evidence-based practice.

CONCLUSION

Specialized knowledge as to the safe and effective use of the antiarrhythmic pharmacotherapy in the intensive care setting can lead to safe and effective rhythm management in patients with complex heart disease.

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.