Practice Variation in Establishing the Adequacy of Beta-Blockers as an Antiarrhythmic Agent in School-Aged Children and Adolescents

Background: Beta-blockers (BBs) are commonly prescribed to manage arrhythmias in children and adolescents without any standardised approach to establish BB adequacy. We invited all Canadian pediatric cardiologists to participate in an anonymous survey to understand practice variation in the assessment of BB adequacy in school-aged children and adolescents with arrhythmia or the potential for arrhythmia. Methods: An electronic survey approved by the Institutional Ethics Board was distributed by e-mail to 96 Canadian pediatric cardiologists who had been active in practice for at least 1 year. Incomplete surveys were excluded. Results: Forty-one cardiologists (43%) responded to all questions in the survey. Thirteen cardiologists (32%) reported always assessing BB adequacy, 17 (41%) did so only for specific arrhythmias, and 11 (27%) reported never performing such an assessment. A total of 19 cardiologists (46%) and 18 cardiologists (44%) reported using Holter monitoring and exercise testing, respectively, to assess beta receptor blockade adequacy. Thirteen cardiologists (32%) considered BB therapy adequate if Holter demonstrated a 20% decrease in heart rate (HR) from baseline, and 10 respondents (24%) defined adequate BB therapy using exercise testing as a 20% decrease in maximal HR or blood pressure from baseline. Conclusion: Despite wide variation in practice, Holter monitoring and exercise testing are commonly used methods to measure the adequacy of BB therapy. There are no standard criteria, but the majority (56%) reported using a 20% decrease in HR or blood pressure from the pretreatment state as a criterion for adequate BB therapy in children and adolescents with arrhythmia or the potential for arrhythmia.