An apparatus, method and computer program, the apparatus comprising: processing circuitry and memory circuitry including computer program code, the memory circuitry and the computer program code arranged to, with the processing circuitry, cause the apparatus to: obtain an audio signal from an audio sensing means wherein the audio signal comprises a subjects heartbeat obtain a further signal from a further sensing means wherein the further signal also comprises the subjects heartbeat use the further signal to identify individual heart beats in the audio signal and analyse the individual heartbeats of the audio signal to enable the audio signal to be classified.
