Millions of Americans are prescribed blood pressure medicines called beta blockers, especially after a heart attack. But a new Italian study finds that these go-to drugs might not work as well for women as they do for men.

"What we found presents a solid case for reexamination of the use of beta blocker therapy for women with hypertension," said study lead author Dr. Raffaele Bugiardini, professor of cardiology at the University of Bologna.

The study couldn't prove a cause-and-effect link, but among patients taking beta blockers, women had a 4.6% higher rate of heart failure than men when going to the hospital with a heart attack or chest pain (angina), the study found.

"For women who have no history of cardiovascular disease and only hypertension, we think it is incredibly important for them to regulate their blood pressure through diet and exercise [first]," Bugiardini said in a news release from the journal Hypertension. His team published the findings in the journal on July 13.

The new research involved almost 14,000 people from 12 European countries. All had been diagnosed with high blood pressure but had not been diagnosed with heart disease.

Besides the nearly 5% higher odds of developing heart failure overall after heart attack, the study found that the type of heart attack mattered.

Women who had a form of heart attack in which a coronary artery is completely blocked and a large part of the heart muscle is unable to receive blood — a so-called "ST-segment elevation myocardial infarction [STEMI]" attack — were 6.1% more likely to have heart failure than men with the same type of heart attack.

In contrast, men and women not taking beta blockers had about the same rate of heart failure, according to the study.

"It's possible that the increased risk of heart failure for women is due to an interaction between hormone replacement therapy and beta blockers, though this information was not collected or tested in our study," Bugiardini said. "This and other potential factors need to be investigated in more depth."

Experts in the United States said the findings show the importance of research focused on women.

"The historic under-representation of women in clinical trials had led to blanket treatments" that might not work equally for men and women, said Dr. Satjit Bhusri, a cardiologist at Lenox Hill Hospital in New York City.

"We know women have different physiology than men," he said. "We also know that women present with heart syndromes differently than men. It is not surprising that women have different physiological reactions to certain medicines when compared to men."

Dr. Evelina Grayver directs the Coronary Care Unit at North Shore University Hospital in Manhasset, New York. She noted that it's long been known that beta blockers "can exacerbate episodes of heart failure for anyone, men and women.

"The use of beta blockers in setting of acute coronary syndrome needs to be approached cautiously — and not only in women," Grayver said. In the meantime, she agreed that "it is imperative to include women in cardiovascular research."