A method for detecting an ectopic signal in an electrocardiogram is disclosed. This method comprises the following steps: detecting consecutive R-R intervals in an electrocardiogram; calculating an average R-R interval for a determinable number of latest R-R intervals; recognizing a signal as ectopic signal if the signal belongs to at least one of two consecutive R-R intervals, wherein i) a first of the two consecutive R-R intervals is significantly shorter than the average R-R interval; and ii) a second of the two consecutive R-R intervals is significantly longer than the average R-R interval, wherein the second R-R interval occurs later than the first R-R interval; wherein the first and the second of the two consecutive R-R intervals are discarded from calculating the average R-R interval, if the signal is recognized as ectopic signal.