MOSCOW -- Russian President Boris N. Yeltsin was hospitalized yesterday for heart trouble, weakening his already flagging public image as well as his prospects for re-election next June.
A presidential spokesman said Mr. Yeltsin, who was taken to the Central Clinical Hospital complaining of severe chest pains, would remain there under observation for "the next several days," but said he was continuing to work from his hospital bed and might even resume his regular schedule next week.
Mr. Yeltsin, 64, became president in 1991 after forging an image of robust invincibility -- as the white-maned pillar of principle who had boldly stood astride a tank to oppose a Communist coup against Mikhail S. Gorbachev.
He may emerge from the hospital with his characteristic hail-fellow-well-met attitude. But even that may not not undo the political damage: "No one will seriously believe he can be re-elected," said Victor A. Kremenyuk, a political scientist at the Russian Academy of Sciences. "How can he count on another four- or five-year term at 64 when he's unhealthy?'"
Though Mr. Yeltsin's career is full of dramatic comebacks after severe political falls, his presidency has been at its rockiest during the past six months.
Presiding over the bloody and unpopular invasion of Chechnya, Mr. Yeltsin saw his popularity drop to single digits in every public opinion survey.
While winning two no-confidence votes in parliament last month, he was forced to fire powerful Cabinet members to satisfy one set of challengers and faces a constitutional challenge from another.
There was also a serious embarrassment when he traveled to an economic summit last month in Canada. While Mr. Yeltsin was engaged in talks there, Russian Prime Minister Viktor Chernomyrdin upstaged the president by negotiating with Chechen terrorists for the release of hostages in the city of Budyonnovsk.
"Before the hospitalization, a lot of these factors made him look weak for '96," said Michael McFaul, senior associate at the Moscow Carnegie Center. "But with this, it may create the setting where he steps down."
Mr. Yeltsin has not declared his candidacy for the June elections. Said to be mindful of his place in history as the first democratically elected Russian leader, Mr. Yeltsin could withdraw from the race -- and that, too, would be a first in the country's history.
Given the president's low popularity ratings, the prospects of a humiliating defeat in June might well make his poor health an welcome excuse not to enter the race, according to Mr. McFaul.
Foreign as well as Russian political observers here suggest that without Mr. Yeltsin, the power elite in the Kremlin would likely close ranks enough to stave off any sort of serious bid for power by extreme nationalists such as Vladimir Zhirinovsky.
Should Mr. Yeltsin choose or be forced not to run for president, Prime Minister Chernomyrdin could be the prime political beneficiary. "People around [Yeltsin] in the Kremlin now know that if anything happens to him unexpectedly they all lose," said Mr. Kremenyuk.
"They may be thinking, 'Boris, enough is enough, it's better you use the rest of the time to pick an heir apparent.' And this of course would be Chernomyrdin."
Mr. Yeltsin's hospitalization cast doubt on the truthfulness of the many previous official claims that his health was excellent, statements made in response to episodes of public drunkenness and his long, unexplained absences from public view.
Early in the day, the Kremlin issued a two-sentence announcement saying Mr. Yeltsin had been hospitalized "in connection with acute ischemic heart disease."
American heart experts said the symptoms described in reports by Mr. Yeltsin's spokesman backed up the doctors' diagnosis. They said it was most likely a form of ischemic heart disease called unstable angina, a common affliction in which narrowing of arteries diminishes the blood supply to the heart.
American doctors said their Russian counterparts would probably treat it in the same way as in the United States -- with drugs or with procedures that widen narrowed passages in arteries.
In severe cases, bypass surgery is used to install new blood vessels.