One of his surgeons said that during his successful campaign to be returned to the Kremlin, he had three "infarcts" - a term Russians use for heart attacks, but which can refer to other stroke-related problems.
Details of his illness came during the extraordinary 50-minute programme called Yeltsin's Heart, screened across the nation to coincide with the second anniversary of the president's quintuple bypass.
The film, which included interviews with his wife, Naina, and surgeons, marked a milestone in the Russian media's coverage of Mr Yeltsin, and is a measure of the distance the country has travelled since the end of the USSR. The broadcast would have been unthinkable in Soviet times when the Kremlin maintained rigid silence about the ill health of its aged occupants.
The programme's content is proof that the fate of Russia hung by a thread in 1996. It has long been accepted that Mr Yeltsin suffered a heart attack in early July between the first and second round of the elections, when he disappeared from view after an energetic campaign performance that saw him dancing in public, travelling widely, and going down an Arctic coal mine. Dr Vladlen Vtorushin, one of the 12-man surgical team which operated on the president, told the programme Mr Yeltsin had five "infarcts", three occurring during the campaign. Another doctor, Sergei Korolyov, stated that were it not for the bypass operation, he would have died within six months. "He certainly wouldn't be alive today."
Surgeons at first thought Mr Yeltsin was too ill to be operated on. A team of German doctors was on hand to conduct an emergency heart transplant. So was the pioneering American cardiologist Michael DeBakey, then 88, who acted as an adviser. Immediately after the seven-hour operation, Dr DeBakey publicly admitted the president "could not have carried on" much longer, but would now be fit enough to play his beloved tennis. However, one surgeon told the programme that, in reality, both doctors and Mr Yeltsin accepted that he would never be completely healthy again. Although the film included an assurance that Mr Yeltsin emerged in sound mental condition, this is unlikely to convince many Russians, given his latest problem.
The 67-year-old president is on holiday at the Black Sea resort of Sochi on the orders of his medical advisers. Although the Kremlin says he is recuperating from exhaustion and high blood pressure, his erratic conduct suggests something more serious may be amiss. Even his aides have now abandoned the pretence that nothing is wrong.
There has been speculation that Mr Yeltsin has Alzheimer's or MID - multi- infarct dementia. A parliamentary bill requiring the president to undergo a medical examination, whose results would have gone to parliament, yesterday fell five votes short of passing. Its authors, who argue that Mr Yeltsin is far too ill to govern, can take consolation in yesterday's widely anticipated Constitutional Court ruling that he cannot run for a third term in 2000.
Natalya Pyaterikiva, script writer of Yeltsin's Heart, told Obshchaya Gazeta newspaper: "We wanted to show through this film that nobody should be given that much power. That is dangerous. Our film is a kind of warning."Reuse content