Abstract: An active medical device equipped with a memory for the storage of medical data such as Holter data and instructions for controlling a microprocessor. This device comprises a micro-processor operating (14) on N bits, and a memory organized in words of 2N bits, with a first sector (22) storing a control software for the microprocessor, and a second sector (24) storing of the elementary medical data of N bits. Each word of the first sector includes N bits of operating code and n bits of error detection and correction code, with 1?n?N. An interfacing circuit (18) allows, according to commands delivered by the microprocessor, to read in parallel N+n bits of a word from the first sector, or to read or to write N bits of low weight of a word of the second sector, or to read or write N bits of high weight of a word of the second sector.