An electrode assembly (10) for a portable ECG signaling device, comprises a thin, flexible electrode support (11) supporting thereon a plurality of electrodes in spaced relationship. The electrodes (V.sub.1, V.sub.2, V.sub.3, V.sub.4, V.sub.5 and V.sub.6, LA, RA, LL) are configured for producing a twelve-lead electrocardiogram, and the electrode assembly is foldable into a compact assembly when not in use.