1. Department of Clinical Research, Cardiology, Bern University Hospital, Bern, Switzerland.
2. InSphero AG, Schlieren, Switzerland.
3. Department of Physiology, Bern University, Bühlplatz, Bern, Switzerland.
4. Department of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany.
5. Cellular Dynamics International, Madison, Wisconsin.