Since the appearance of the Holter monitor, it was conceived as a continuation of the electrocardiogram which serves to detect cardiac diseases, many signs of progress have been made of these devices, which go hand in hand with technology, mainly in elements microcontrollers and micro sensors, such as the transmission of data in real time. With this has been minimized the shortcomings to provide greater comfort and better results of the analysis. This article contains an analysis of these ambulatory measuring devices from the beginning to the current research, analyzing the use of this element for the detection of cardiac diseases, pros and cons of this kind of devices by emphasizing great change that has been generated in recent years with the technological progress.