David Sirota, advisor and speechwriter to Sen. Bernie Sanders Bernie SandersSirota reacts to report of harassment, doxing by Harris supporters Republicans not immune to the malady that hobbled Democrats The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election MORE (I-Vt.), believes that the heart attack that Sanders suffered in early October has helped "personalize" the Senator's proposed Medicare for All plan."

"At one level he's been pushing the same agenda and the same message with the same values for 40 years," Sirota said in an interview Wednesday.

"At another level, I think that the heart attack, it personalized in some ways the message that he's fighting for."

One way or another, Sanders has surged in the polls since he returned to the campaign trail after heart surgery.

A recent CNN/UNH poll shows that the longtime Vermont Senator has ahead of Sen. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.) and former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE in New Hampshire. In the poll, Sanders came in at 21 percent, Warren followed with 18 percent and Biden rounded out the top three with 15 percent.

"After the heart attack there was a lot of talk that Bernie Sanders was done, it's over, the campaign is finished," Sirota noted.

"I think Time Magazine wrote, that we've have some of the best, if not the best, three weeks of the entire campaign," he continued. "And I think that's felt in Iowa, it's felt in New Hampshire."

In addition to the favorable polling numbers in the Granite State, the Sanders campaign has also upped its game in Iowa, releasing a digital ad that features Rep. Alexandra Ocasio-Cortez (D-N.Y.)

Ocasio-Cortez formally announced her endorsement of Sanders at a campaign rally in her home district of the Bronx on Oct. 19.

"We should have a society that guarantees 21st century human economic rights," the progressive firebrand says in the ad.

"What makes Senator Sanders very different is that his aspiration is our aspiration. That's the kind of leadership that I think we need right now."