Recommendations and levels of evidence in the guidelines of the European Society of Cardiology: current scenario and time trends. Issue 2 (17th October 2019) - Caldeira, Daniel; Marques, Ana; Almeida, João; Rodrigues, Tiago; Alves, Mariana; David, Cláudio; Gonçalves, Nilza; Costa, João; Ferreira, Joaquim J; Pinto, Fausto J