A system for detecting arrhythmias in cardiac activity, comprising: memory configured to store specific executable instructions; one or more processors configured, when executing the specific executable instructions, to: obtain a far field cardiac activity, CA, data set that includes far field CA signals for beats; apply a feature enhancement function to the CA signals to form an enhanced R-wave feature in the CA data set; calculate an adaptive sensitivity level based on the enhanced R-wave feature from one or more beats within the CA data set; automatically iteratively analyze a beat segment of interest by: comparing the beat segment of interest to the current adaptive sensitivity level to determine whether one or more R-waves are present within the beat segment of interest; repeating the iterative analyzing operation while progressively adjusting the adaptive current sensitivity level until i) the one or more R-waves are detected in the beat segment of interest and/or ii) the current sensitivity level reaches the sensitivity limit; and detecting an arrhythmia within the beat segment of interest based on a presence or absence of the one or more R-waves; and record results of the detecting of the arrhythmia. memory configured to store specific executable instructions; one or more processors configured, when executing the specific executable instructions, to: obtain a far field cardiac activity, CA, data set that includes far field CA signals for beats; apply a feature enhancement function to the CA signals to form an enhanced R-wave feature in the CA data set; calculate an adaptive sensitivity level based on the enhanced R-wave feature from one or more beats within the CA data set; automatically iteratively analyze a beat segment of interest by: comparing the beat segment of interest to the current adaptive sensitivity level to determine whether one or more R-waves are present within the beat segment of interest; repeating the iterative analyzing operation while progressively adjusting the adaptive current sensitivity level until i) the one or more R-waves are detected in the beat segment of interest and/or ii) the current sensitivity level reaches the sensitivity limit; and detecting an arrhythmia within the beat segment of interest based on a presence or absence of the one or more R-waves; and record results of the detecting of the arrhythmia. obtain a far field cardiac activity, CA, data set that includes far field CA signals for beats; apply a feature enhancement function to the CA signals to form an enhanced R-wave feature in the CA data set; calculate an adaptive sensitivity level based on the enhanced R-wave feature from one or more beats within the CA data set; automatically iteratively analyze a beat segment of interest by: comparing the beat segment of interest to the current adaptive sensitivity level to determine whether one or more R-waves are present within the beat segment of interest; repeating the iterative analyzing operation while progressively adjusting the adaptive current sensitivity level until i) the one or more R-waves are detected in the beat segment of interest and/or ii) the current sensitivity level reaches the sensitivity limit; and detecting an arrhythmia within the beat segment of interest based on a presence or absence of the one or more R-waves; and comparing the beat segment of interest to the current adaptive sensitivity level to determine whether one or more R-waves are present within the beat segment of interest; repeating the iterative analyzing operation while progressively adjusting the adaptive current sensitivity level until i) the one or more R-waves are detected in the beat segment of interest and/or ii) the current sensitivity level reaches the sensitivity limit; and detecting an arrhythmia within the beat segment of interest based on a presence or absence of the one or more R-waves; and record results of the detecting of the arrhythmia.