Government curbs on secondhand smoke in New York led to nearly 4,000 fewer hospital admissions for heart attacks in 2004, according to a new statewide study.

In the study, published yesterday in the American Journal of Public Health, the State Department of Health reviewed nearly half a million hospital admissions for what is known as acute myocardial infarction, or heart attack.

Researchers concluded that such admissions fell more than 8 percent in 2004 from what would have been the expected level of admissions for that year. That was equivalent to 3,813 fewer hospital admissions, they said.

At an average cost of $14,772 for each heart-attack admission, the total savings is about $56.3 million, researchers said.

The 2003 state ban on smoking in many public places is “a public health intervention that hardly costs anything, so to accrue that kind of savings from an inexpensive intervention is really unparalleled,” said Ursula Bauer, the director of the Health Department’s tobacco control program and an author of the study.

The study is more comprehensive than similar studies that covered only a few hospitals in a few counties. It analyzed 10 years of existing data, from 1994 to 2004, covering all of the state’s 62 counties and more than 250 hospitals. It looked at data for admissions for 462,396 heart attacks.

Researchers focused on the year after the July 2003 enactment of the Clean Indoor Air Act, which prohibited smoking in bars, restaurants, banquet halls and places where workers were paid tips or wages.

Using a statistical model incorporating the 10 years of heart-attack data, state health researchers identified factors associated with heart attacks: people suffer more heart attacks in winter; there are different rates in different counties; heart attacks are dropping anyway because of better medical care; and, more important, local governments have been curbing smoking since 1995.

If researchers, in effect, subtract these factors that affect heart attack rates, then what is left is likely to be the effect of the 2003 ban, said Harlan R. Juster, the Health Department’s director of tobacco surveillance, evaluation and research and an author of the study.

By this indirect reasoning, the number of hospital admissions for heart attacks should have been 49,225 for 2004, but was 45,412.