A device adapted to attach to a subject for detecting an ECG signal of the subject. The device includes a first, a second, and a third electrode, where the electrodes form an orthogonal configuration. Two channels of ECG data can be obtained using a common electrode, and can be further combined to obtain a further channel using vector mathematics. The channel combination can be performed at vector angles suitable for optimizing the detection of various features of the ECG spectra of the subject. A method of using an implantable cardiac device together with surface-attached wireless sensor(s) is also provided where the acquired data from the implantable cardiac device and from the surface-attached wireless sensor(s) are both used for diagnosing patients heart conditions and administering appropriate therapies.
