Kate is a 35 year old dentist who presents with a 1 year history of palpitations. She states that she is a keen runner, but increasingly she has noted that she is experiencing palpitations whilst she is running. She denies any chest pain. She feels she is short of breath but puts this down to running. She states that when she stops running it takes about 10 minutes for the palpitations to stop. Sometimes she feels faint but has never collapsed or lost consciousness. She wants to run in the London marathon this year but would like to know if she should be worried about her heart. Examination is unremarkable today and her pulse is regular. There is no family history of heart disease, she has never smoked and her BMI is 19. She is not on any medications and has no previous medical problems.
What would be the most appropriate action?