The study presents a comparison of the results received from dogs with dilated cardiomyopathy (DCM) that died during the first 30 d of observation and from dogs with DCM that survived the first 30 d after the ECG. No differences were noted in the duration of QT or QTc in healthy dogs and dogs with DCM. QTcd was significantly higher in dogs with DCM and in dogs with DCM, which did not survive over 30 d of observation and dogs with DCM that died after the 30th d of observation. The presence of T-wave alternans (TWA) was more frequently observed in dogs with DCM (85% of the dogs) that died in less than 30 d during the observation. QTcd and TWA seem to be a useful non-invasive diagnostic tool to anticipate the risk of cardiac death in dogs with DCM.