Health and Human Services Secretary Margaret M. Heckler wants Medicare to pay for its beneficiaries' heart transplants and shortly is expected to announce regulations covering such a plan, administration and Capitol Hill sources said yesterday.

Heckler's plan would include stringent medical standards for choosing recipients, sources said.

Medicare does not pay routinely for heart transplants for any of its 30 million beneficiaries but has paid for some experimentally. Some private insurance groups finance them for their policyholders.

Authorizing Medicare payments for heart transplants would mean a major rules change and could cost hundreds of millions of dollars in several years.

Sources said Heckler has indicated to some in the medical community that she wants to proceed on the theory that transplant technology is beginning to be used regularly and can no longer be considered merely experimental. They said the major stumbling block is fear of break-the-bank expenses.

The number of available, healthy hearts for transplant is quite small, however. One estimate done for HHS puts the total of usable hearts for all patients at 300 to 1,000 a year for the next several years, although it could rise to 8,000 thereafter. The relative scarcity is due partly to the limited number of people who die in the hospital with an organ suitable for transplant and partly to their families' reluctance to authorize donations.

This "natural" limit on hearts is considered an automatic brake on costs, especially if Medicare transplants were restricted to those who were otherwise healthy and were not extremely old.

A recent draft study for HHS by the Batelle Human Affairs Research Centers of Seattle, never publicly released, said that 172 heart transplants were performed nationwide in 1983.

The draft study said that, based on the number of people who might have been eligible for heart transplants under current rigorous medical standards, 86 Medicare transplants would have been performed in 1980. That figure might be about 100 transplants a year now, experts said; at an average cost of $80,000 to $90,000 each, the cost to Medicare would be about $8 million to $9 million.

However, some experts said this number assumes very rigorous current standards, generally limiting transplants to those under 55 and otherwise in good health.

HHS had no comment on the report.