Fontan Fitness Trial

Home-based, Digital Intervention to Increase Physical Activity in Patients With the Fontan Circulation

The goal of this randomized control trial is to learn about physical fitness and exercise habits in children aged 10-17 with the Fontan Circulation through a home-based, digital exercise intervention. The main questions it aims to answer are:

• Does a home-based, digital intervention increase physical activity (PA) in youth with the FC compared to enhanced usual care?
• Does a home-based, digital intervention increase physical fitness in youth with the FC compared to enhanced usual care?
• Do multi-level factors (medical, neurodevelopmental, sociodemographic, neighborhood) impact the effectiveness of the digital intervention?

Researchers will compare participants in the enhanced usual care arm to those in the exercise intervention arm to see if the digital intervention is effective.

All participants will wear a PA tracker for 12 months and complete testing at baseline, 6 months, and 12 months.

In addition, participants in the exercise intervention arm will complete a 6-month exercise intervention with the following components:

• aerobic exercise
• resistance exercise
• engagement strategies

Study Overview

• Status: Recruiting
• Conditions: Congenital Heart Disease; Single-ventricle
• Intervention / Treatment: Behavioral: Digital Exercise Intervention

Detailed Description

The Fontan Circulation is associated with poor exercise performance and reduced quality of life. Current standard of care encourages physical activity (PA) in this population, but few structured interventions exist. Participants will be randomly assigned to either enhanced usual care (PA tracker and standard encouragement) or an interactive digital intervention that includes personalized aerobic and resistance exercises with behavioral engagement strategies. This study will evaluate a home-based, digital intervention delivered through a mobile health platform to promote PA and improve fitness among youth with FC.

The study will recruit up to 200 participants aged 10-17 years with FC. After initial testing and a two-week run-in period, 120 participants with peak VO2 between 45% and 80% of predicted norms will be randomized. The intervention will last 6 months, followed by a 5.5-month monitoring phase. Outcomes will include changes in PA (measured via accelerometry), peak VO2, muscle strength, body composition, and quality of life.

• Study Type: Interventional
• Enrollment (Estimated): 200
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Elizabeth Goldmuntz, MD; Phone Number: 215-590-3354; Email: goldmuntz@chop.edu
• Study Contact Backup: Name: Zoe Lincoln, MS; Email: lincolnz@chop.edu

Study Locations

• United States
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • Recruiting
      • Children's Hospital of Philadelphia
      • Contact: Zoe Lincoln, MS; Email: lincolnz@chop.edu
      • Contact: Elizabeth Goldmuntz, MD; Email: goldmuntz@chop.edu
      • Principal Investigator: Elizabeth Goldmuntz, MD
      • Sub-Investigator: Jonathan Mitchell, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Fontan Circulation present
• Girls ≥11 years of age or menstruating must have negative urine pregnancy test
• Neurodevelopmental capacity to complete all study procedures
• Physical capacity to complete all study procedures
• English speaking with at least one English speaking parent/guardian
• To enroll in the randomized control trial, percent predicted peak VO2 <80% of age-sex matched normal controls on the baseline exercise stress test (EST)

Exclusion Criteria:

• Inability to complete an EST at any time (i.e. limited physical or executive function)
• Uncontrolled lymphatic disorders
• Uncontrolled noncardiac conditions
• Exercise induced or uncontrolled arrhythmias
• Pacemaker or internal cardiac defibrillator (ICD)
• Peak VO2 <45% age-sex predicted
• Having had or under consideration for a heart transplant
• Pregnant or lactating females
• Parents/guardians or subjects who, in the opinion of the investigator, may be non-compliant with study schedules or procedures

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Digital Exercise Intervention; The exercise intervention arm includes access to a digital application to receive the following over the 6-month intervention: personalized plans for aerobic-based PA; personalized resistance exercise sessions; engagement strategies.	Behavioral: Digital Exercise Intervention; Subjects randomized to the intervention arm will receive the same as the enhanced usual care arm but will be additionally exposed to: (1) personalized plans for aerobic-based PA, (2) personalized resistance exercise sessions, and (3) financial and non-financial engagement strategies. These intervention components will be delivered continuously using an advanced digital health informatics platform during the 6 months of the intervention. The intervention will be overseen and supplemented by the exercise physiologist, who will meet with participants on a weekly, then biweekly and finally monthly basis over 6 months.
No Intervention: Enhanced Usual Care; The enhanced usual care arm will receive their usual care in addition to a passive physical activity tracker device. No intervention materials will be delivered to these participants over the course of their enrollment in the study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
MIMS-units	Change in total volume of physical activity (PA) operationalized as a Monitor Independent Movement Summary (MIMS) units, expressed as a percentile based on what is expected for their age and sex.	0 to 12 months. Evaluated from baseline to 6 months, baseline to 12 months, and 6 to 12 months.
Absolute peak VO2	Change in absolute peak VO2, the maximum amount of oxygen the body consumes during exercise without regard to body weight (liters/minute).	0 to 12 months. Evaluated from baseline to 6 months, baseline to 12 months, and 6 to 12 months.
Percent predicted peak VO2	Change in percent predicted peak VO2, the maximum amount of oxygen the body consumes during exercise expressed as a percentage of what is expected for their age and sex.	0 to 12 months. Evaluated from baseline to 6 months, baseline to 12 months, and 6 to 12 months.
Leg lean mass	Change in leg lean mass presented as a z-score. Leg lean mass z-score compares an individual's leg muscle mass to the average for their age and sex, with values below -2.0 indicating lower-than-expected muscle mass.	0 to 12 months. Evaluated from baseline to 6 months, baseline to 12 months, and 6 to 12 months.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
MVPA	Change in time spent in moderate to vigorous physical activity (MVPA), in terms of minutes per day.	0 to 12 months. Evaluated from baseline to 6 months, baseline to 12 months, and 6 to 12 months.
Forearm strength	Change in forearm strength measured via handgrip test and presented as a z-score. Z-scores are used to standardize measurements across individuals with different demographics (i.e. age, sex, body size).	0 to 12 months. Evaluated from baseline to 6 months, baseline to 12 months, and 6 to 12 months.
Lower extremity strength	Change in lower extremity strength measured via knee and ankle peak torsion and presented as a z-score.	0 to 12 months. Evaluated from baseline to 6 months, baseline to 12 months, and 6 to 12 months.
PROMIS Pediatric Profile-25 T-score	Change in Patient-Reported Outcomes Measurement Information System (PROMIS) Pediatric Profile-25. This 25-item questionnaire provides a T-score based on physical function, anxiety, depression, fatigue, peer relationships and pain. Children and parents will complete a PROMIS questionnaire. Children will answer questions about themselves and parents will answer questions in regard to their child.	0 to 12 months. Evaluated from baseline to 6 months, baseline to 12 months, and 6 to 12 months.
PCQLI score	Change in Pediatric Cardiac Quality of Life Instrument (PCQLI) total and sub-scale scores (i.e. Disease Impact, Psychosocial Impact).The PCQLI is a cardiac-specific health-related quality-of-life instrument. Children will answer questions about themselves and parents will answer questions in regard to their child.	0 to 12 months. Evaluated from baseline to 6 months, baseline to 12 months, and 6 to 12 months.

Collaborators and Investigators

• Sponsor: Children's Hospital of Philadelphia
• Collaborators: University of Pennsylvania; National Heart, Lung, and Blood Institute (NHLBI)
• Investigators: Principal Investigator: Elizabeth Goldmuntz, MD, Children's Hospital of Philadelphia

Study record dates

Study Major Dates

• Study Start (Actual): June 9, 2025
• Primary Completion (Estimated): April 1, 2029
• Study Completion (Estimated): April 1, 2029

Study Registration Dates

• First Submitted: April 2, 2025
• First Submitted That Met QC Criteria: April 2, 2025
• First Posted (Actual): April 9, 2025

Study Record Updates

• Last Update Posted (Actual): April 13, 2026
• Last Update Submitted That Met QC Criteria: April 7, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Fontan; adolescents; digital health; randomized control trial; exercise intervention; Single ventricle disease
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Heart Diseases; Congenital Abnormalities; Cardiovascular Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Univentricular Heart; Heart Defects, Congenital
• Other Study ID Numbers: 24-022619; 1R61HL171110-01A1 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: NHLBI data sharing regulations will be followed. No data will be shared before study conclusion.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No