In order to satisfy a need for a high reliability mortality risk prediction method and device while minimizing the efforts to be taken by the patient and health personnel, the present invention provides a method for assessing a mortality risk of a cardiac patient based on respiratory sinus arrhythmia, said method comprising the following steps. Step A: Computing the mean respiratory sinus arrhythmia during inhalation and/or exhalation for a plurality of breathing cycles of said patient. Step B: Assessing the mortality risk of said patient based on said computation. A device for performing said method is also disclosed.
