Background: Many single ventricle congenital heart diseases are palliated through a set of surgeries, ending in the Fontan procedure.  Regular exercise can improve exercise capacity and is increasingly recognized as safe in this population. With the increasing popularity of consumer-based activity monitors such as “Fitbit”, it is important to explore the idea that giving patients a device is a way to get them engaged in exercise and monitor heart activity from an outpatient management standpoint. 

Methods:  We prospectively studied the compliance with Fitbit activity monitoring in a cohort of 19 prospectively enrolled adolescents after Fontan palliation.  Subjects were seen in clinic between November 2018 and April 2019 and received a Fitbit Blaze device which was to be worn as continuously as possible for 3 months. Fitbit-wearing compliance was measured by looking at daily resting heart rate data. At the completion of the 3 months, subjects were asked to complete a questionnaire to evaluate their acceptance of the devices and to gauge their interest in using technology to augment their outpatient medical care.

Results:  We enrolled 19 participants (47% female) at a mean age of 15.3 years.  There was active participation (compliance over 50%) in six participants (2 female), with continuous participation (compliance over 75%) in two participants. A total of five questionnaires were returned. All six of the participants who were compliant with monitoring were also participants in other research studies that likewise involved an exercise component.

Conclusion:  Unprompted compliance with a Fitbit activity monitor in a cohort of adolescent patients after Fontan was quite poor.  While ambulatory monitoring may be a useful adjunct to exercise training programs, the mere presence of the device does not appear to be sufficient to motivate this cohort to be compliant, at least without prompting. Perhaps if a Fitbit was given to Fontan subjects, it would be beneficial if it were tied to another training program. More work is needed to understand the role of ambulatory activity monitors in comprehensive wellness programs for this cohort of patients.