The US House of Representatives has narrowly voted in favour of a healthcare bill drafted to repeal and replace the Affordable Care Act, also known as Obamacare, BBC report. The measure, voted in on Thursday 217 to 213, now heads to the US Senate, where it faces an uphill battle. Twenty Republicans went against the bill while not a single Democrat voted in favour of it. The vote against former President Barack Obama's signature domestic achievement, which enabled 20 million more Americans to get health insurance, is President Donald Trump's biggest legislative win since he took office in January. However, in the Senate, where the Republican majority is narrow, lawmakers are expected to subject the new bill to much greater scrutiny and skepticism. Speaking with dozens of Republican lawmakers huddled behind him in front of the White House, Trump said he felt "so confident" that the bill would pass the Senate as well. "It will be an unbelievable victory," he said. Obamacare "is dead. If we don't pay lots of ransom money over to the insurance companies, it would die immediately," he said. "What we have is an incredible well-crafted [replacement plan]". Al Jazeera's Alan Fisher, reporting from Washington, DC, said: "It is unusual, to say the least, that the president would take a victory lap before the bill passed both houses of Congress." "So it shows how important this is to Donald Trump, to his supporters to be seen," he said. Passed in 2010, Obama's Affordable Care Act expanded Medicaid, the government insurance programme for the poor, provided income-based tax credits to help the poor buy insurance on individual insurance markets set up by the law, and required everyone to buy insurance or pay a penalty. Republicans have blamed it for driving up healthcare costs.