Abstract: The device senses Natural Heart Acceleration (NHA), isolating at least one segment (t) thereof corresponding to an isovolumetric phase, such as isovolumetric contraction (P1, P2) and/or isovolumetric relaxation (P3, P4). Preferentially, the action of isolation of the aforesaid segment is made starting from the electrocardiogram (ECG) signal. Among other things, the device may be used to carry out pacing functions (pacemaker, defibrillator, pacer cardioverter defibrillator) and/or to pick up, possibly by telemetry, data on the myocardial function and/or also to control a system of drug administration.