Republican newcomer Brian Fitzpatrick and Democratic State Rep. Steve Santarsiero rolled to victories Tuesday in their primaries for the Bucks County-based Eighth Congressional District, ending a hotly contested race that has drawn attention from national party leaders.

With nearly 80 percent of the statewide vote tallied, Fitzpatrick, brother of Republican incumbent Rep. Mike Fitzpatrick, easily topped Marc Duome, a neuropsychologist, and Andy Warren, a former Bucks County commissioner and official with the state Department of Transportation, according to unofficial results.

On the Democratic side, the race was much closer. By a nearly 3-2 ratio, Santarsiero led Shaughnessy Naughton, a Democratic scientist and businesswoman in her second run for the nomination, the unofficial results showed.

The district was one of the few contested congressional primaries across the region. In the Seventh District, which includes Delaware County and a slice of Montgomery County, U.S. Rep. Patrick Meehan, a Republican, handily fended off a challenge from Stanley Casacio, a real estate investor and developer from Montgomery County.

Meehan will again face Mary Ellen Balchunis, a La Salle University political science professor who coasted to victory in the Democratic primary over William Golderer, a Philadelphia pastor.

In the Ninth Congressional District - which stretches across central Pennsylvania and is traditionally considered a safe seat for the GOP - Republican Rep. Bill Shuster barely hung on to his seat, unofficial results showed. In an unexpected development, tea party-backed candidate Art Halvorson trailed by less than 2,000 votes.

The tight race came as a surprising challenge for Shuster, the House transportation and infrastructure committee chairman and a mainstay in his district.

The Eighth District race, however, had suspense throughout the primary, tension that likely will continue in the fall. Experts have dubbed the seat a swing suburban district toss-up, with fewer than 3,000 registered voters separating Democrats and Republicans. National Democrats have declared the district one of five House seats they believe they could wrest from the GOP.

The winner in November will replace Mike Fitzpatrick, who served four terms. But the seat in recent history has not been solidly GOP, fluctuating between the parties for a little more than the last decade.

Brian Fitzpatrick's first campaign was not without controversy. While labeling himself as an outsider - the 42-year-old left his job as an FBI agent this year - the younger Fitzpatrick quickly gained steam as the favored GOP candidate, despite a late entrance and questions about whether he illegally began campaigning for the seat too soon.

Fitzpatrick was unavailable for comment Tuesday night. But in a brief victory statement, he declared, "The American dream is worth fighting for, and I will fight for us."

On the Democratic side, the race between Santarsiero and Naughton, considered from the beginning to be more evenly matched, had been hostile and fervid in recent weeks, with both sides trading accusations and campaign complaints.