It is disclosed an electronic system (1 ) to control the acquisition of an electrocardiogram. The system comprises a portable electronic device (2) and a mobile electronic device (3). The mobile electronic device comprises an optical device (3-1) for acquiring real-time images of a portion of a human body, comprises a screen (3-2) and comprises a processing unit (3-3) connected to the optical device and to the screen. The portable electronic device (2) comprises a first (2-1), a second (2-2) and a third (2-3) electrode configured to generate a first (S1_r), a second (S2_r) and a third (S3_r) detecting electrical signal respectively representing the current generated on the skin by the activity of the heart of a human being in the respective points wherein the first, second and third electrodes are positioned on said portion of the human body. The processing unit of the mobile electronic device comprises an electrodes placement guiding module (3-3.1) for the first, second and third electrode. The electrodes placement guiding module is configured to receive a plurality of real-time images (l
