An intruder broke into the Pelosis’ California home on Friday October 28.
The suspect, 42-year-old Canadian national David DePape, allegedly confronted Mr Pelosi in his bedroom and stating that “he was looking for Nancy”.
He then attacked Mr Pelosi with a hammer leaving him injured and in hospital receiving treatment for a week.
Mr DePape – who is currently being held without bail – pleaded not guilty this week to a number of charges, including attempted murder.
A number of pro-Democrat supporters in the US media subsequently attempted to blame the Republicans for the attack.
According to the poll the Republicans are leading 51 percent to 46 percent ahead of the Democrats in the House of Representatives election.
At the lowest point this would mean, the Democracy Institute claims, that the Republicans have 245 seats with a majority of 55 but at the top end they could have 265 seats with a majority of 95.
It is a major reversal for Ms Pelosi, whose tenure as House Speaker will come to an end, and the Democrats who currently hold a majority with 220 to 212 seats and three vacancies.
In the Senate race, the poll suggests that likely voters who are willing to cast the ballot on Tuesday split 49 percent to 46 percent in favour of the Republicans.
This has led the Democracy Institute to increase its Senate seat projection of gains by one in favour of the Republicans from 53 to at least 54 with the Democrats left with 46.
But the majority could be as big as 57 to 43.