Women are more than twice as likely to die after a heart attack than men, a new study suggests.
The findings highlight the need for greater awareness of the risks of heart disease in women, researchers say.
According to the study women aged 55 and below also had to wait 15 minutes longer for treatment after arriving at hospital.
Previous studies have found that women who have a heart attack when a major artery feeding into the heart is completely blocked - ST-elevation myocardial infarction (STEMI) - have a worse prognosis during their hospital stay compared with men.
Experts suggest this may be because of their older age, increased numbers of other conditions, and stents being used less to open blocked arteries.
Study author Dr Mariana Martinho of Hospital Garcia de Orta, in Almada, Portugal said: "Women of all ages who experience a myocardial infarction are at particularly high risk of a poor prognosis.
"These women need regular monitoring after their heart event, with strict control of blood pressure, cholesterol levels and diabetes, and referral to cardiac rehabilitation.
"Smoking levels are rising in young women and this should be tackled, along with promoting physical activity and healthy living."
The new research compared short and long-term outcomes after STEMI in women and men, and looked at whether any sex differences were apparent in both premenopausal (55 years and under) and postmenopausal (over 55) women.
The study included 884 patients, with an average age of 62 years and 27% were women.
Women were older than men (average age 67 versus 60 years) and had higher rates of high blood pressure, diabetes and prior stroke, researchers found.
Men were more likely to be smokers and have coronary artery disease.
While the time between symptoms and treatment with stents did not differ between women and men overall, premenopausal women had a significantly longer treatment delay after arriving at hospital than their male peers - 95 versus 80 minutes.
Researchers compared the risk of adverse outcomes between women and men after taking into consideration factors such as diabetes, high cholesterol, hypertension, coronary artery disease, heart failure, chronic kidney disease, peripheral artery disease, stroke and family history of coronary artery disease.
At 30 days, 11.8% of women had died compared with 4.6% of men.
At five years, nearly one-third of women (32.1%) had died compared with 16.9% of men.
Meanwhile more than one-third of women (34.2%) experienced major adverse cardiovascular events within five years compared with 19.8% of men.
Dr Martinho said: "Women had a two to three times higher likelihood of adverse outcomes than men in the short and long-term even after adjusting for other conditions and despite receiving PCI within the same timeframe as men."
The researchers conducted a further analysis in which they matched 435 men and women according to risk factors for heart disease including hypertension, diabetes, high cholesterol and smoking.
In matched patients over 55 years of age, all adverse outcomes measured were more common in women than men, the study found.
Some 11.3% of women died within 30 days compared with 3.0% of men.
At five years, one-third of women (32.9%) had died compared with 15.8% of men.
Dr Martinho said: "Postmenopausal women had worse short and long-term outcomes after myocardial infarction than men of similar age.
"Premenopausal women had similar short-term mortality but a poorer prognosis in the long term compared with their male counterparts.
"While our study did not examine the reasons for these differences, atypical symptoms of myocardial infarction in women and genetic predisposition may play a role.
"We did not find any differences in the use of medications to lower blood pressure or lipid levels between women and men."
She concluded: "The findings are another reminder of the need for greater awareness of the risks of heart disease in women.
"More research is required to understand why there is gender disparity in prognosis after myocardial infarction so that steps can be taken to close the gap in outcomes."
The research, which has not yet been peer reviewed, was presented on Monday at Heart Failure 2023, a scientific congress of the European Society of Cardiology.