Cardiac surgery often involves connecting the patient to a heart-lung machine and removing a small part of the right atrium. With the patient's consent, small isolated atrial muscle strips, called trabeculae, can be prepared from this tissue. Trabeculae are a unique translation tool that can be used to reproduce in human myocardium what has been found in cell models and/or in vitro/in vivo studies in laboratory animals. In an organ bath, trabeculae are exposed to hypoxia/reoxygenation, and the contractile force of the trabeculae is a measure of their functionality.