Seven imprisoned Irish nationalist terrorists in British-ruled Northern Ireland ended their 53-day-old hunger strike tonight when it appeared that one of them, Sean McKenna, was about to die.

After a "comatose" McKenna was transferred to a civilian Hospital from the Maze Prison outside Belfast, the other six hunger strikers told prison officials they wanted food and medication for themselves and McKenna, 26.

Prison officials said it was uncertain whether all seven could be nursed back to health. Both McKenna and Thomas McKearney, 28 have suffered possibly irreparable damage to their eyesight from vitamin deficiencies.

The end of the hunger strike surprised both British officials and Irish nationalist terrorist leaders because the British government has refused to give in to the hunger strikers' demands that they and hundreds of other convicted terrorists be treated as political prisoners rather than as criminals.

Irish nationalist supporters of the hunger strikers said tonight that 30 other imprisoned terrorists who had recently joined the hunger strike also would begin eating Friday morning. They suggested that the strikers had relented after seeing a planned British government statement setting out prison terms that correspond to some of the hunger strikers' demands.

But British officials said last night that no deal had been made with the hunger strikers and they had not been shown the statement, which is to be given by Prime Minister Margaret Thatcher's Ulster secretary, Humphrey Atkins, in Parliament Friday.

British officials said Atkins intended only to spell out flexibility in prison rules on clothing, work and other conditions available to all inmates in Northern Ireland. Convicted terrorists make up three-fourths of the prison population there.

The end of the strike eases tension that had been building here and in Northern Ireland in anticipation of a critical phase in the hunger strike shortly before Christmas. British officials had been braced for an upsurge of terrorism if any of the hunger strikers had died.

They also feared that Christmas-season deaths of protesting Catholic Irish nationalist prisoners, despite their convictions for crimes including murder, attempted murder and armed robbery, might recover for the terrorists some of their waning sympathy in the minority Roman Catholic community in Northern Ireland or in the neighboring, predominantly Catholic Repbulic of Ireland.

The failure of the hunger strikers to win political status, or to stir greater support for their cause among Irish Catholics, was already being seen by some British politicians tonight as a significant blow to the terrorists' long-held campaign for recognition of their claim to be fighting a war of liberation. The strikers want to force a British withdrawal from Ulster and the province's unification with Ireland.

It is still possible that some terrorists will retaliate against this setback, with a repeat of past holiday bombings in Northern Ireland or elsewhere in Britian.

Asked tonight why he thought the hunger strikers had given up, Northern Ireland Secretary Atkins said, "I think they must have grasped that [political status] is not going to be given to them now.

"Frankly, I don't think they have achieved anything by the hunger strike," Atkins added on BBC televison. "What they have done is cause a good deal of tension in Northern Ireland and a great deal of distress to their friends and family."

Earlier today, when her government still expected that some strikers might die, Thatcher reiterated in Parliament that political prisoner status could not be given to "people who had committed murder and other terrible crimes" because " we would be putting at risk the lives of many innocent men, women and children."

Shortly before midnight, several hours after the hunger strike ended, the Provisional Irish Republican Army issued a statement acknowledging Thatcher's contention that the strike had "totally and utterly failed." It added, "We make it clear that failure by the British government to act in a responsible manner toward ending the conditions which forced us on to a hunger strike will not only lead to inevitable and continual strife within [the Maze Prison] but will show quite clearly the intransigence of the British government."

This appeared to indicate that serveral hundred other convicted terrorists would continue the rest of their four-year-old protest campaign for political prisoner status. They have refused to wear prison clothes, do prison work or use prison toilets. They wear only blankets and smear their excrement on their cell walls.