[1] Univ Zurich, Inst Physiol, Zurich, Switzerland
[2] Univ Zurich, Ctr Integrat Human Physiol ZIHP, Zurich, Switzerland
[3] Univ Zurich Hosp, Dept Cardiol, Ctr Cardiovasc, CH-8091 Zurich, Switzerland
[4] Univ Roma La Sapienza, Fac Med 2, Div Cardiol, Osped SantAndrea, Rome, Italy