Described are computer-based methods and apparatuses, including computer program products, for automated atrial fibrillation detection. Based on morphology analysis, atrial beats are recognized and used for R-R intervals analysis. "Die. invented system creates R-R interval classes and estimates irregularity indicator value (deviation) for each class. The total average R-R intervals deviation for all analyzed atrial beats is calculated by weighted averaging of the irregularity indicator values of all classes, where the weight values are equal to the class sizes. FIG.1
