Rapidly swelling imports helped trim US economic growth to its slowest pace in a year during the second quarter, the Commerce Department reported yesterday, though its key driving forces remained robust.

Gross domestic product, the broadest gauge of total economic activity, expanded at a revised 1.8 per cent annual rate in the spring quarter instead of 2.3 per cent as reported a month ago.

That was less than half the first quarter's 4.3 per cent pace of advance and was the slowest growth since a matching 1.8 per cent rate in the second quarter last year.