In the cardiology field, in recent years, we have witnessed an exponential increase in the use of both invasive and non-invasive instrument diagnostics. Particularly after an acute coronary syndrome, instrumental examinations, especially non-invasive ones, are often prescribed inappropriately until they almost completely replace the clinical evaluation. Their correct use, on the contrary, would require the choice of a test to be prescribed according to the epidemiological and clinical context of the individual patient. The strategy of early diagnosis, obtainable through instrumental screening and borrowed from oncological pathologies, was transferred 'tout court' in the cardiovascular field without any scientific basis, replacing the pharmacological or non-pharmacological intervention, such as the appropriate lifestyle, aimed at reducing cardiovascular risk factors. The guidelines of the main scientific societies define the most appropriate paths in the management of the coronary heart disease patients, both in the immediate post-acute phase and in the chronic phase. Although the guidelines sometimes show an excessive simplification of clinical problems, in an age in which the control of health expenditure has become a priority the correctness of the indications is an indispensable objective, being incontrovertible that a test is indicated only when an instrumental examination is able to modify the diagnostic-therapeutic path and the outcome of the patient.