Coefficient of variation

The coefficient of variation (V) is calculated by the formula: V = 100 * standard deviation / M, where: M is the mathematical expectation. The coefficient of variation in physical meaning does not differ from the standard deviation, however, it is normalized to the average value of the rhythm. Based on the value of the coefficient of variation, conclusions are made on background arrhythmias and on the stationarity of the state. The normal value of V is 35%. A decrease in V indicates the stabilization of the rhythm, and an increase indicates an increase in arrhythmia. With a significant, over 10% indicator, indicates the presence of cardiac arrhythmias.

Source: http://csp-athletics.ru/images/doc/metod/control/metod-control-10.pdf