Determinants and Implementation of Hybrid Cardiac Rehabilitation in Adolescents and Young Adults With Congenital Heart Disease: Insight From the QUALIREHAB Study

BACKGROUND: The QUALIREHAB (Cardiac Rehabilitation in Youth With Congenital Heart Disease) trial demonstrated the efficacy of a hybrid cardiac rehabilitation model in adolescents and young adults with congenital heart disease. This post hoc mixed-methods study aimed to identify baseline predictors of clinical improvement and to characterize key components supporting implementation and scalability. METHODS: Seventy participants aged 13 to 25 years from the intervention arm were analyzed. Clinical improvement was defined as a clinically meaningful increase in cardiopulmonary fitness (increase in peak oxygen uptake ≥3.5 mL/kg per min) or health-related quality of life (Pediatric Quality of Life Inventory increase ≥4.3 points). Multivariable logistic regression models identified predictors of clinical improvement. Semistructured interviews with patients and health care professionals explored experiences, barriers, and implementation mechanisms. RESULTS: The absence of prior cardiac surgery or interventional catheterization was independently associated with short-term improvement in peak oxygen uptake. At 1 year, male sex and lower baseline ventilatory anaerobic threshold were associated with greater peak oxygen uptake improvement. Lower baseline ventilatory anaerobic threshold was also the only predictor of clinically meaningful health-related quality of life improvement. Qualitative findings highlighted the accessibility and acceptability of the hybrid model but underscored the need for higher-intensity and more varied exercise modalities, integrated digital tools, continuous psychological support, family involvement, and structured postrehabilitation follow-up to sustain long-term benefits. CONCLUSIONS: Among treated participants, male sex, absence of prior cardiac surgery, and marked baseline deconditioning were associated with greater clinical improvement, supporting a shift from standardized toward tailored cardiac rehabilitation in congenital heart disease. By addressing key logistical and psychosocial barriers, this scalable framework offers a pragmatic model for routine care implementation and may be transferable to other pediatric chronic conditions. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03690518.