Center for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, P.O. Box 4956 Nydalen, N-0424, Oslo, Norway; Center for Heart Failure Research, Oslo University Hospital, P.O. Box 4956 Nydalen, N-0424, Oslo, Norway; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, P.O. Box 1171 Blindern, 0318, Oslo, Norway. Electronic address: a.o.awoyemi@medisin.uio.no.