Method and apparatus for producing information indicative of cardiac malfunctions

An apparatus comprising:

• a sensor system responsive to motion including cardiovascular motion, the sensor system comprising at least one of the following:
• an accelerometer, a gyroscope, an inertial measurement unit comprising both an accelerometer and a gyroscope,
• a processing system for processing an analysis signal produced by the sensor system,
• wherein the processing system is configured to:
• form a first indicator quantity indicating degree of concentration of autocorrelation of the analysis signal to a point that corresponds to zero time difference between analysis signal samples whose mutual correlation is expressed by the autocorrelation,
• form a second indicator quantity indicating spectral entropy of the analysis signal, and
• determine an indicator of cardiac malfunction on the basis of at least the first indicator quantity and the second indicator quantity.