BNP Chairperson Begum Khaleda Zia has suffered a mild cardiac arrest and a stent has been placed in her heart, said the party's secretary general Mirza Fakhrul Islam Alamgir.
Earlier, it was said that a coronary angiogram will be performed on her, who has been admitted to Evercare Hospital in Dhaka after as she suddenly fell ill.
The BNP chief was taken to the coronary care unit (CCU) of the hospital at 3:20am on Saturday.
Earlier in the day, the 10-member medical board, formed to ensure the treatment of Khaleda, sat in a meeting at Evercare Hospital to review her health condition.
The BNP chief left her Gulshan residence for the hospital at 2:55am and was admitted there at 3:15am, said her media wing member Sayrul Kabir Khan.
Hearing the news of Khaleda's illness, Fakhrul rushed to her Gulshan residence and later went to the hospital.
Coming out of the hospital around 4:30am, Fakhrul said after some primary tests, the doctors found that she has cardiac problems.
"Madam's condition is stable now. How complicated her problem is can be confirmed after she undergoes different tests, especially an angiogram," he said.
A medical board will analyse Khaleda's condition and her medical reports at 10:30am Saturday and decide the next course of treatment, Fakhrul added.
He hoped that Khaleda would recover as she did in the past.
The BNP leader urged the country’s people to pary for her speedy recovery.
The BNP chairperson last went to Evercare on April 6 for health check-ups.
Khaleda, a former prime minister, has been suffering from various ailments, including liver cirrhosis, arthritis, diabetes, kidney, lung and eye problems.
The 76-year-old was last admitted to Evercare on November 13 last year where she was diagnosed with liver cirrhosis.
On February 1, Khaleda returned home after an 81-day stay at the hospital as she was suffering from internal bleeding caused by liver cirrhosis.
The former prime minister was sent to the Old Dhaka Central Jail as a lower court sentenced her to five years' imprisonment in the Zia Orphanage Trust corruption case on February 8, 2018.
Later, she was found guilty in another corruption case the same year.
Amid the Covid-19 pandemic, the government temporarily freed Khaleda from jail through an executive order suspending her sentence on March 25, 2020, with conditions that she will stay at her Gulshan home and not leave the country.