In this study, carried out on a sample of more than 300 patients and parents, we observed that the knowledge of congenital heart diseases is deficient, on the basis that most of them did not describe it adequately and almost all of them were unable to simply draw the heart defect. It has been described in the literature9 that a good knowledge of the disease and its understanding in an optimal way, is associated with lower stress figures, better emotional state, greater satisfaction with health personnel and better compliance with therapy. For this reason, it is important to know the degree of knowledge of patients about their disease.
In the healthcare setting, it is common for the diagnosis of CHD to be explained in a simple manner and with understandable drawings. It is also normal clinical practice for this information to be repeated in successive consultations, but it is true that healthcare personnel often do not ensure that this information transmitted is properly understood.
The results of our study are to some extent comparable to those of previous research. Matley et al.10 in their study of children with CHD and their parents appreciate that knowledge about the heart defect is inadequate, and that many of them are unable to name the disease correctly. In line with their results, in our study, it was found that although the majority of patients (children, adolescents and adults) and their parents know the name of the heart disease, few are able to adequately describe what the disease consists of, and only a small percentage are able to represent it in a graphic way by making a drawing.
Another study by Wang et al.11 has simply demonstrated the poor knowledge of heart abnormalities when asked to explain the heart defect with a drawing. They observed that, although there are exceptions, the drawing process is generally consistent with the level of knowledge of the heart disease.
One group of special interest is adolescents, since this is a transitional stage to adulthood, where they must be responsible for their own health care. Increasingly, transition programmes are being developed to prepare adolescents for this, as some studies have shown12. A critical element in transition programmes is patient health education, to improve the level of awareness of their illness and increase the concern for adopting appropriate self-care behaviours. This will be influenced by the degree of maturity of each adolescent and their sense of responsibility.
In our study, we found that the age of the patients is an important factor when evaluating the knowledge they present about their disease, observing that as the patient gets older, they know more about their heart disease. This may be influenced by the fact that in the transition consultation from the paediatric to the adult stage, it is likely that greater efforts are made to explain to the patients themselves what their disease consists of, since in the field of child cardiology, information is occasionally directed at parents.
On the other hand, we have seen that patients with complex CHD know the name of their heart disease better than those with simple CHD. This may be related to the fact that more complex and unusual names attract more attention and are therefore more easily remembered, or that more emphasis was placed on explanation. In addition, patients with complex congenital heart disease generally require a greater number of visits to the doctor and more interventions, so they end up becoming more familiar with the disease and therefore with its name. However, when it comes to evaluating the understanding of the disease, in a descriptive way and through the elaboration of a drawing, we have seen that, in general, both the patients themselves and the parents of those who have complex heart disease, are the ones who present the worst results when they have to show what they know about the pathology.
For all the above reasons, this study would support the need to educate patients from an early age, explaining to them what their disease consists of, and not only to their parents, using language adapted to the child, so that it can support their transition to an independent adult in the future. On many occasions, professionals assume that parents are the ones who should explain their illness to their children, but there are parents who, in order to protect their children, prefer not to know the extent of their pathology. Furthermore, many of the parents are not clear about the repercussion of heart disease on their children's lives, and cannot adequately transmit to them the knowledge that the professionals are trying to explain.
Wang et al.13 point out the importance of having an adequate knowledge of the disease, observing in their study, that a better knowledge of the cardiac anomaly improves the quality of life of the patients and reduces the psychological impact generated by the disease.
The present study shows methodological limitations that require the results to be interpreted with caution. There is no standardized instrument to assess knowledge of CHD in pediatric patients or their parents, so we have used a small non-validated questionnaire developed at the authors' own unit, initially as a quality control. Caution should be exercised when generalizing the results, since it is difficult to extrapolate the results being a study carried out in a single center, although the sample is large and it is a national reference center for the treatment and monitoring of CHD at the time of the study.