Advances in overall management have led to an increasing number of adolescents with congenital heart disease reaching adulthood. This study aimed to evaluate the health-related quality of life in adolescents with heart disease, and examine its relationship with the adolescents’ knowledge and understanding of their congenital heart disease, its severity, and its relationship to the degree of anxiety and depression, feeling of optimism and sense of coherence experienced by the adolescents together with their social support.

Adolescents with heart disease were recruited from an ambulatory setting at a tertiary centre. Patients completed self-report questionnaires including the Paediatric Quality of Life Inventory 3.0-Cardiac Module, a questionnaire assessing the adolescents’ knowledge of their cardiac condition, the Hospital Anxiety and Depression Scale, Multidimensional Scale of Perceived Social Support, Life Orientation Test-Revised, and Sense of Coherence-13, supplemented by clinical information provided by the attending cardiologists. A total of 114 patients aged 12–20 years were recruited over 15 months. In all, 98% of patients were in New York Heart Association class I. Their health-related quality of life was found to positively correlate with a low level of anxiety and depression (Pearson correlation, r = −0.57, p < 0.001), a good knowledge of their cardiac condition (r = 0.31, p < 0.01), feelings of optimism (r = 0.39, p < 0.001), adequate social support (r = 0.27, p < 0.01), and a strong sense of coherence (r = 0.24, p < 0.01).

Adolescents’ knowledge and understanding of their cardiac abnormality together with an improved sense of well-being had a positive influence on their health-related quality of life.