1. From the Departments of Physiology and Cardiothoracic Surgery (C.v.D., I.E.v.G., L.M.R., A.H., M.K., F.W.P.), Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands; Biometry and Clinical Epidemiology (C.K.), Research Department, IRCCS Fondazione Policlinico San Matteo, Pavia, Italy; and Fondazione Cardiocentro Ticino (A.A.), Lugano, Switzerland.