an atrial fibrillation classification system collects celectrocardiogram signals and converts them to a frequency , time , or phase domain representation for analysis . an evaluation stage extracts energy density profile over a range of frequencies , time intervals , or phases , which is then summed and normalized to form dispersion metrics . the system then analyzes the dispersion metrics , in their respective domains , to determine whether a patient is experiencing an arrhythmia and then to classify the type of arrhythmia being experienced .