Disclosed are a system and a method for determining a probability for a person to have arrhythmia. The system (100) comprises means for measuring heartbeat interval of the person (102) for a period of time； an accelerometer； means for measuring an electrocardiogram (116) of the person (102)； a user interface (114) for providing information and alerts, and a processor (112). The processor (112) is configured to detect a period of rest of the person (102), based on measurement data from the accelerometer； analyse the measured heartbeat interval to determine a probability of having arrhythmia for the person； generate an alert to the user interface (114), if the probability exceeds a predetermined threshold value, to alert the person to measure the electrocardiogram with the means for measuring an electrocardiogram (116)； analyse the measured electrocardiogram to determine if the probable arrhythmia is confirmed； and indicate the confirmed arrhythmia to the person (102) via the user interface (114).
