Catecholaminergic Polymorphic Ventricular Tachycardia Type 1

The goal of this observational study is to evaluate exercise testing and daily physical activity in children and adolescents who are diagnosed with an inherited arrhythmia. The main question it aims to answer is: Does maximum heart rate during controlled exercise tolerance testing accurately reflect maximum heart rate and peak exercise levels during free living daily physical activity in children and adolescents diagnosed with an inherited arrhythmia? Participants will: * Complete routine exercise tolerance testing * Record daily physical activity and exercise over two weeks, while wearing an activity and heart rate monitor and digit diary. * Complete a physical activity questionnaire at the end of two weeks.