A system provides synthesized chest lead signals of a conventional 12 lead electrocardiogram (ECG) signal set. The system adaptively derives ECG chest lead signals for a plurality of the six ECG chest lead signals of a conventional 12 lead ECG signal set. The system includes an input processor for receiving data comprising two measured ECG chest lead signals comprising a particular two of the six ECG chest lead signals of a conventional 12 lead ECG signal set and receiving associated information identifying the particular two signals of the six ECG chest lead signals. A data processor in the system uses the information identifying the particular two signals of the six ECG chest lead signals for identifying and selecting coefficients from a plurality of stored coefficients and applying a transformation using the selected coefficients to the data comprising the two measured ECG chest lead signals to derive data representing a plurality of non-measured ECG chest lead signals. An output processor processes the data representing the plurality of non-measured ECG chest lead signals for output. The selected coefficients are patient non-specific.