Ground ECG electrode in physiological signal generated by CMRR-MB sequences

Hi everyone,

We’ve got physiological data generated by CMRR-MB sequences (>=R015, >=VD13A), that we have later extracted into log files using the script extractCMRRPhysio.m (

For the ECG signal, there are 4 electrodes (ECG1, ECG2, ECG3 and ECG4) and we suspect that one of those might be a ground electrode. We tried to find this information in the Siemens manual as well as googling it, but we found nothing.

Does anyone know something about this?

Thanks a lot in advance!!