This paper describes the design and construction of a portable electrocardiogram (Holter) for the acquisition and storage of the first and second bipolar derivation ECG and precordial lead. The prototype built has the advantage over similar commercial equipment, that downloads the stored signals in analog form, which lets you use any virtual instrumentation platform, such as LabVIEW, BIOPAC or otherwise, and does not rely on communication protocols. The output signals of the Holter, were compared with the input provided by an ECG patient simulator, where he found a great similarity in the amplitudes, shapes, and frequency spectrum without varying the heart rate, the signal of interest study by cardiologist in case of patients with arrhythmias.