An apparatus for determining an indicator parameter relating to a subject comprising at least an input line (2, 4) for receiving electrical signals coming from a electrodes (3), receiving a signal coming from a peripheral sensor (5) predisposed to operate in a predetermined peripheral section of the subjects body a control unit (6) connected to the input line and configured for determining a value of an indicator value (iHAT) as a function of the instant of generation (TGj) of a pressoric wave in relation to the heartbeat.
