A method and a wireless cardiac monitoring device to measure and transmit cardiac physiological signals of a subject. The device comprises a patch configured to be in contact with a skin surface of the subject. The patch comprises a plurality of electrodes and at least one wire-free module, embedded in the patch. The wire-free module comprises a patch orientation detection module to detect an orientation of the patch on the subject using a plurality of sensors. The wire-free module also comprises a processing module to select at least two pair of electrodes from the plurality of electrodes based on the detected orientation of the patch and process one or more bio-potential signals corresponding to the at least two pair of electrodes selected, as the physiological signals. The wire-free module further comprises a transmission module to transmit the physiological signals to an external device for further processing.