|Zardari suffered numbness and twitching in his left arm and had lost consciousness for a few seconds [EPA]
Pakistan's president has arrived home after receiving treatment for nearly two weeks in the United Arab Emirates, officials from his ruling party said.
A special flight carrying Asif Ali Zardari, his daughter and personal staff landed at an air force base in the port city of Karachi, Manzoor Wasan, the home minister of Sindh province, told the AFP news agency.
Pakistani officials said security had been boosted on roads from the airport to Zardari's residence in Karachi.
Zardari, who was discharged from a Dubai hospital on Wednesday, has been sufffering from a transient heart attack, in which blood supply to a part of the nervous system is cut off, but not for long enough to kill tissue as in a stroke, according to Pakistani officials.
Farhatullah Babar, Zardari's spokesman, told news agencies on Sunday before the president left Dubai that he was "perfectly fine" but did not give further details.
Zardari's sudden flight to Dubai on December 6 had sparked rumours he might be considering stepping down, possibly under pressure from the military.
His office says he suffered numbness and twitching in his left arm and had lost consciousness for a few seconds.
Although he has survived numerous crises and calls for his resignation, he has come under increasing pressure from Pakistan's powerful military for allegedly seeking US help to curb its power.
The row centres on a memo sent in May to then-chairman of the US Joint Chiefs of Staff, Admiral Mike Mullen, seeking help over fears of a military coup following the US raid that killed Osama bin Laden.
Zardari's return came hours before the Supreme Court is due to hear a petition by opposition leader Nawaz Sharif demanding to know who was responsible for writing the memo.
The existence of the document came to light when Pakistani-American businessman Mansoor Ijaz wrote in the Financial Times newspaper that Zardari feared the military might overthrow his government.
Ijaz accused Husain Haqqani, the president's close aide and ambassador to Washington, of crafting the memo with Zardari's support.
Haqqani denies any involvement but he has already been restricted from leaving Pakistan and was forced to resign as ambassador last month.
Pakistan is also battling perhaps its worst crisis in US relations after NATO air strikes killed 24 Pakistani soldiers on November 26.
Prime Minister Yousuf Raza Gilani is responsible for the day-to-day running of the fragile coalition government, which is understood to have tense relations with the military, which effectively controls foreign policy.
Gilani on Sunday denied a military intervention was imminent against his government, saying, "There is no room for a martial law in Pakistan".