[1] Hosp Valle De Hebron, Serv Cardiol, Barcelona 08035, Spain
[2] Univ Erlangen Nurnberg, Erlangen, Germany
[3] Univ Essen Gesamthsch, Essen, Germany
[4] Hippokrateion Hosp, Athens, Greece
[5] S Orsola Univ Hosp, Bologna, Italy
[6] CNR, Inst Clin Physiol, I-56100 Pisa, Italy
[7] Hammersmith Hosp, London, England
[8] Hosp Clin San Carlos, Madrid, Spain