"Our family is concerned about his health. If anything happens to our father, the government will be held responsible," he tweeted.
Zardari was admitted to the VIP ward of the cardiology department of the Pakistan Institute of Medical Sciences (PIMS) on October 22. He was declared out of danger after several tests, according to a report in the Pakistani media.
The former President had complained of backache, weakness and anxiety, while being lodged in Adiala jail of Rawalpindi.
On Monday, Zardari was put on Holter monitor by PIMS medical board to check variations in his heartbeat. "The device has been put on because of continuous variations in the patient's heartbeat," PIMS media coordinator Waseem Khawaja told Dawn.
The patient would stay at the hospital till his condition became normal, he added.
A Holter monitor is a battery-operated portable device that records the heart's activity for 24-48 hours, or longer, depending on the requirement.
According to him, a patient is put on the device when he/she complains of dizziness, which could be because of low heartbeat. "Zardari is sick. He is diabetic, has arthritis and has received stents," he said. Zardari had all these medical issues when he was the President as well, he said.
PPP leader Rehman Malik, a day earlier, sought relief for Zardari and his sister Faryal Talpur on the pattern of legal remedy provided to former Prime Minister Nawaz Sharif and his daughter Maryam.
"Zardari and Faryal Talpur are high-profile undertrials. They must not be treated like convicted persons," he remarked.
Zardari was arrested by the National Accountability Bureau (NAB) on June 10 after cancellation of his anticipatory bail by the Islamabad High Court in the fake bank accounts case.
NAB Additional Prosecutor General Jahanzeb Bharwana had told the court the watchdog was investigating billions of rupees transactions through 28 bank accounts for which the investigation team required custody of the accused persons.
( With inputs from IANS )