Democratic Reps. Heath Shuler and Larry Kissell of North Carolina appear to be feeling the heat from their party's base. Both voted against healthcare reform and each ceded almost 40 percent of the primary vote to virtually unknown challengers.

Shuler bested challenger Aixa Wilson by about 60 percent to 40 percent, according to unofficial results, but Wilson edged Schuler by almost 600 votes in Buncombe County, home of Asheville.

Kissell defeated challenger Nancy Shakir 63 to 37 percent.

Meanwhile, Sen. Richard Burr (R-N.C.) cruised to the nomination with some 80 percent of the vote, according to the unofficial results. The Democratic primary has broken into a two-way race between Secretary of State Elaine Marshall and former state Sen. Cal Cunningham. 

Updated at 10:06 p.m.