No....not specifically Atlantic Canada at all. "eh" is used most frequently by residents of Manitoba, Ontario, and New Brunswick, somewhat less frequently in Quebec, Saskatchewan, British Columbia, Prince Edward Island, and the three territories, and rarely if ever in Nova Scotia, Alberta and Newfoundland. This may reflect cultural differences among the provinces, perhaps including the physical distance between various areas of Canada and major American population centres.
And although they say it is used somewhat less frequently in Quebec....I don't find this to be true. There is some question as to the origin of the term, a popular theory is that the "eh" sound is similar to the "ey" sound that a native French speaker will stereotypically say when pronouncing the word "Hey".
(most of that interpretation from wiki)
All I know, is it isn't used by most people I know.
