The goal of this observational study is to pursue a multimodal approach to identify the molecular signatures and immune signalling molecules of various myocardial diseases and thereby contribute to improving diagnosis and therapy. The main aim is: -Identification of molecular profiles (e.g., proteome, lipidome, metabolome) and immune signalling profiles that are specifically associated with different myocardial diseases and the post-heart transplantation course. Participants already receiving an endomyocardial biopsy as part of their regular medical care will be enrolled. An additional biopsy sample will be taken for the above mentioned research.