1. A computer-implemented method for analyzing a physiological signal, comprising: selecting a first time interval containing a pattern of interest in a recording of the physiological signal; computing respective values of a characteristic of the physiological signal in a plurality of time segments within the first time interval; concatenating the computed values to form a signature of the pattern of interest; and identifying a further occurrence of the pattern of interest in the physiological signal during a second time interval by matching the signal in the second time interval to the signature.