The electrocardiograph (200) of the invention is suitable for capturing a twelve-lead electrocardiogram from signals representative of the cardiac activity of a patient and acquired with the help of at least nine electrodes. The electrocardiograph comprises a body (210) having a front face (211) and at least one arm (212, 213) suitable for being folded beside the body and pivotable about an axis that is substantially parallel to the front face. Each arm is adapted to form a variable dihedral angle with the front face so that the substantially concave surface (214) formed by the front face and the or each arm and having six precordial electrodes (201-206) distributed thereon, is capable of adapting to the patients morphology so as to enable the precordial electrodes to be properly positioned on the patients chest. The electrocardiograph also includes means enabling said good positioning of the precordial electrodes on the patients chest to be maintained.