Saw my cardiologist today&had an ecg done.on the ecg report, there is the line"poor data quality, interpretation may be adversely affected".what does it mean?should i have a repeated ecg to make sure it's accurate? cardiologist told me it was normal.

It means that the: technical quality of the tracing is poor (probably baseline artifact or electrical noise on the recording) and that the computer is uncertain about the exact interpretation because of this. The human doctor will be able to account for this so I would trust his/her interpretation. It's surprising that you would have this in a Cardiologist's office but not a big concern.