A device provides methods for detecting cardiac signals from facial biopotential sensors (110) is disclosed. The device comprises a set of facial electrodes a processor (116), coupled with the set of facial electrodes. The processor (116) configured to control a detection of a cardiac signal from a facial biopotential signal (114) measured with the set of facial electrodes. Moreover, one or more facial biopotential electrodes for measuring the facial biopotential signal (114) may be integrated in or at a contact surface of head support structures such as a headgear support or respiratory treatment mask. Moreover, a controller of a respiratory treatment apparatus may serve as a cardiac signal detector by processing the facial biopotential signal (114) from the sensors (110) and may make control adjustments or generate warnings based on an evaluation of detected signals.
