Evidence based medicine (EBM) is the conscientious,explicit, and judicious use of the current best evidence inmaking decisions about the care of individual patients. Inother words, the practice of evidence based medicinestands on integrating individual clinical expertise with thebest available external clinical evidence from systematicresearch. This implies that EBM is not super imposable toguidelines for the patient approach, but, rather, it is itspillar [1]. Indeed, Sackett stressed that ‘‘Evidence basedmedicine is not cookbook medicine’’ and it requires abottom-up approach that integrates the best external evi-dence with individual clinical expertise and patients’choice. This task is not that easy and simple: the applica-tion of EBM to clinical practice requires a personalinterpretation of all guidelines and flowcharts, becauseexternal clinical evidence can inform, but can neverreplace, individual clinical expertise.The paper by Costantino et al., in Internal and Emer-gency Medicine [2] shows that, indeed, this is the case ineveryday clinical practice. In fact, they show how manydifferences can be found in the comparison of cohorts withchronic heart failure enrolled in the clinical trials on whichEBM is based with patients referred to the heart failureoutpatient clinic of the L. Sacco Hospital. The differencesbetween the two groups of patients regard NYHA class,ejection fraction (EF), co-morbidity, ischemic cause andage.This gives us many points to address. First of all, a greatnumber of patients admitted to the Italian outpatient clinicswould have never been included in most internationalrandomized clinical trials (RCTs), and this is due to strictexclusion and inclusion criteria that pick out patients withfew additional risk factors. RCTs are regarded as the mostreliable method by which a treatment can be assessed [3],but very often they are not representative of the generalpopulation of patients with heart failure, because manyeligible patients are excluded. In fact, patients with sig-nificant co-morbidity or severe left ventricular dysfunctionwere excluded by many RCTs. In addition, several reviewshave documented that the proportion of older researchsubjects enrolled in clinical trials is disproportionatelylower than the number of elderly patients in the populationfrom which these subjects are drawn [4]. This can explainwhy age is one of the strongest differences between theproportion of patients admitted to the Italian clinic and thepatients enrolled in heart failure clinical trials.Another important difference regards the etiology ofheart failure. Heart failure is the end point of a number ofdisease processes which reduce the contractility of theheart, causing breathlessness, fatigue and fluid retention[5]. It is commonly caused by systolic or a diastolic dys-function, but many patients with heart failure have bothtypes of dysfunction. The two etiological patterns have adifferent course and a different prognosis. The first one iseasily detected by reduction of EF, while the seconddepends too much on heart rate and it is not easily iden-tified in the clinical practice to be used as inclusioncriterion in RCT. This explains why Costantino could not