1. A method for detecting arrhythmia from a physiological signal, the method comprising: extracting, using processing equipment, a plurality of derived value data sets associated with the physiological signal; determining, using processing equipment, a plurality of arrhythmia features based on the derived value data sets, wherein the arrhythmia features comprise an entropy feature; and generating, using processing equipment, an arrhythmia indicator based on the arrhythmia features.