Fewer U.S. heart attack survivors are having another heart attack within a year, a new study finds.

Rates of recurrent heart attacks, hospitalization for heart failure, and deaths within a year have gone down in heart attack survivors, according to the study published Sept. 21 in the journal Circulation. However, the rates are still high, researchers said.

The study analyzed data from more than 770,000 women and more than 700,000 men in the United States who were hospitalized for a heart attack between 2008 and 2017.

During that time, the study found, overall rates of recurrent heart attack fell in men and women, with women showing more declines. However, the rate didn't decline in women ages 21-54 or in men ages 55-79.

Recurrent heart disease event rates (either heart attack or undergoing a procedure to open clogged arteries) went down. 

Hospitalization due to heart failure rates also declined in men and women, while death rates from any cause in those 66 and older went down. 

"Improvements in the emergency treatment of heart attacks and better treatment options for people who survive a heart attack may explain the overall decline," said study author Sanne Peters, a senior lecturer at The George Institute for Global Health in collaboration with Imperial College London.

It's not clear why recurrent heart attacks in younger women and older men didn't decline.

"In women, it could be that younger women and their treating physicians may be more likely to miss signs of worsening heart disease," Peters said in a journal news release.

"We expected to see a decline in the rate of events, however, we did not expect the rates to differ between the sexes. It may be that the improvements in men were achieved before our study period, leaving less room for improvement in the most recent decade. It could also be that the attention paid to heart disease in women over recent years has resulted in the greater gains," she said.

"However, regardless of the improvements, the rates of recurrent events in people who survived a heart attack are still very high in both sexes. Patients should speak with their doctors to ensure that the get the right treatments to prevent secondary events and must make sure that they adopt or maintain a healthy lifestyle," Peters concluded.