In the absence of evidence-based guidelines, paediatric cardiologists monitor patients in the ambulatory care setting largely according to personal, patient, institutional, and/or financial dictates, all of which likely contribute to practice variability. Minimising practice variability may optimise quality of care while incurring lower costs. We sought to describe self-reported practice patterns and physician attitudes about factors influencing their testing strategies using vignettes describing common scenarios in the care of asymptomatic patients with tetralogy of Fallot and d-transposition of the great arteries. We conducted a cross-sectional survey of paediatric cardiologists attending a Continuing Medical Educational conference and at our centre. The survey elicited physician characteristics, self-reported testing strategies, and reactions to factors that might influence their decision to order an echocardiogram. Of 267 eligible paediatric cardiologists, 110 completed the survey. The majority reported performing an annual physical examination (66-82%), electrocardiogram (74-79%), and echocardiogram (56-76%) regardless of patient age or severity of disease. Other tests (i.e. Holter monitors, exercise stress tests or cardiac MRIs) were ordered less frequently and less consistently. We observed within physician consistency in frequency of test ordering. In vignettes of younger children with mild disease, higher frequency testers were younger than lower frequency testers. These results suggest potential practice pattern variability, which needs to be further explored in real-life settings. If clinical outcomes for patients followed by low frequency testers match that of high frequency testers, then room to modify practice patterns and lower costs without compromising quality of care may exist.