Device for assessing a mortality risk of a cardiac patient based on at least one vital sign or biosignal of said patient, said device comprising: a. A data provision unit being configured to provide at least one recording of electrocardiogram as at least one data function of said at least one vital sign or biosignal of said patient. b. A data processing unit being configured to process data of said at least one data function for assessing a mortality risk of said patient by performing the following actions: i. Selecting at least one data sequence from said at least one data function according to a predetermined routine, wherein the data sequence contains at least one data point correlating with a ventricular extrasystole, said device being characterized by: ii. Computing a specific T-wave response to a ventricular extrasystole based on said at least one selected data sequence by calculating the T-wave amplitude quotient between the first post-extrasystolic T-wave amplitude and the mean of T-wave amplitudes preceding and/or succeeding said first post-extrasystolic T-wave amplitude. iii. Assessing a mortality risk of said patient based on said computed T-wave response to a ventricular extrasystole by allocating said patient to a high risk group in case the number of T-wave amplitude quotients calculated to be less than 1 per 30 minutes recording of said data function is greater than zero. a. A data provision unit being configured to provide at least one recording of electrocardiogram as at least one data function of said at least one vital sign or biosignal of said patient. b. A data processing unit being configured to process data of said at least one data function for assessing a mortality risk of said patient by performing the following actions: i. Selecting at least one data sequence from said at least one data function according to a predetermined routine, wherein the data sequence contains at least one data point correlating with a ventricular extrasystole, said device being characterized by: ii. Computing a specific T-wave response to a ventricular extrasystole based on said at least one selected data sequence by calculating the T-wave amplitude quotient between the first post-extrasystolic T-wave amplitude and the mean of T-wave amplitudes preceding and/or succeeding said first post-extrasystolic T-wave amplitude. iii. Assessing a mortality risk of said patient based on said computed T-wave response to a ventricular extrasystole by allocating said patient to a high risk group in case the number of T-wave amplitude quotients calculated to be less than 1 per 30 minutes recording of said data function is greater than zero. i. Selecting at least one data sequence from said at least one data function according to a predetermined routine, wherein the data sequence contains at least one data point correlating with a ventricular extrasystole, said device being characterized by: ii. Computing a specific T-wave response to a ventricular extrasystole based on said at least one selected data sequence by calculating the T-wave amplitude quotient between the first post-extrasystolic T-wave amplitude and the mean of T-wave amplitudes preceding and/or succeeding said first post-extrasystolic T-wave amplitude. iii. Assessing a mortality risk of said patient based on said computed T-wave response to a ventricular extrasystole by allocating said patient to a high risk group in case the number of T-wave amplitude quotients calculated to be less than 1 per 30 minutes recording of said data function is greater than zero.