Abstract: It is disclosed an electronic system to control the acquisition of an electrocardiogram. The system comprises a portable electronic device and a mobile electronic device. The mobile electronic device comprises an optical device for acquiring real-time images of a portion of a human body, a screen and a processing unit. The portable electronic device comprises a first, a second and a third electrode. The processing unit of the mobile electronic device comprises an electrodes placement guiding module for the first, second and third electrode. The screen is configured to display a real-time image representing said portion of the human body and further comprises a first positioning mark, a second positioning mark and a third positioning mark representing the positions wherein to apply the first, second and third electrode respectively.