ATLANTA (AP) _ Federal health officials released statistics Thursday pointing to an increase in heterosexually transmitted AIDS cases in the United States.

The total, including some foreign-born patients now presumed to have gotten the disease through heterosexual activity, stands at 862, or nearly 4 percent of AIDS cases in the United States.

The new numbers came as the national Centers for Disease Control announced that it has begun including in its ''heterosexual cases'' category all AIDS patients not in the major risk categories who were born in a country where heterosexual contact is the chief way of spreading the deadly disease.

Of the 862 heterosexual cases, 483 occurred in people born in those countries, chiefly Haiti and some central and east African nations.

It's not certain that those people got the disease through heterosexual activity, but ''it's our best guess,'' said Dr. Timothy Dondero, chief of surveillance for the CDC's AIDS task force.

''We know they're not ... homosexual; they're not IV drug abusers,'' Dondero said. The major risk categories for AIDS are homosexual men and intravenous drug abusers.

The other 379 cases presumed to have been heterosexually transmitted occurred in people not in the major risk groups who reported heterosexual contact with an AIDS patient or someone at increased AIDS risk.

Even without the foreign-born cases now listed as heterosexual, the CDC's statistics point to an increase in heterosexual transmission of AIDS. Out of the 379 U.S.-born heterosexual cases, 156, or 41 percent, have been reported in the first seven months of 1986.

''The heterosexual cases are increasing at a faster rate than the overall cases,'' Dondero said, noting that 31 percent of AIDS cases overall occurred this year.

Still, heterosexual AIDS cases are a small part of the total, Dondero noted. As of Monday, the CDC had reports of 22,792 AIDS cases in adults in the United States, with 862, or 3.8 percent, listed as heterosexual cases. A total of 323 cases have occurred in children.

The majority of adult cases - 14,939, or 66 percent - have occurred among homosexual or bisexual men; 3,889 cases, or 17 percent, have occurred among abusers of injectible drugs, while 1,823 cases, or 8 percent, have been among men who are both drug abusers and homosexual or bisexual.

Acquired immune deficiency syndrome, which is believed to be caused by a virus and transmitted through blood and body fluids, cripples the body's ability to fight off disease. More than 55 percent of the AIDS patients in the United States have died.

Until April 1985, the CDC listed Haitian-born people as a separate risk group. Some studies have shown that as many as one in 20 Haitians have been exposed to the virus that causes AIDS, compared with one in 10,000 Americans.