Sen. Arlen Specter (D-Pa.) is in a dead heat with former Rep. Pat Toomey (R-Pa.), according to a new poll. Specter holds a statistically insignificant 45 percent to 44 percent lead over Toomey in a Quinnipiac University poll released Wednesday.The 29-year Senator from Pennsylvania announced in April that he was switching parties to run for re-election as a Democrat in 2010 because he said he could not win a Republican primary against Toomey. Specter appears to be on solid ground in the Democratic primary with Rep. Joe Sestak (D-Pa.), who has all but officially announced his candidacy. Specter led Sestak in the poll, 55 percent to 23 percent.Specter also showed his highest disapproval rate and lowest approval rate with voters since his 2004 primary match with Toomey — a contest the Senator barely won. Specter had a 47 percent approval rate and a 46 percent disapproval rate. The poll took the opinion of 1,173 Pennsylvania voters from July 14 to 19, with a sample of 512 Democrats. The poll had a margin of error of 2.9 points.