Despite the development of better diagnostic techniques and new modes of therapy, management of cardiac arrhythmias is still difficult. The lack of standardization in the indications of each technique has increased the risk of overtreatment and unnecessary cost. This paper describes the minimal requirements necessary for the different techniques and the appropriate information that should be collected from each. A well taken clinical history and a 12-lead EKG give very important information for the decision on when and how to treat.