Today, more and more children with complex heart lesions and underlying cardiomyopathies reach adulthood. This results in a wide range of new clinical problems encountered in later life. In particular, idiopathic restrictive cardiomyopathy is initially treated by medication to reduce symptoms, but at end-stage disease, heart or heart-lung transplantation becomes unavoidable. We describe the case of a patient with restrictive cardiomyopathy and a persistent extra-cardiac left-to-right shunt, where we hypothesize that the shunt may protect against haemodynamic deterioration in end-stage restrictive cardiomyopathie.