dr. nancy snyderman. >> reporter: maxine levy remembers when she woke up with a cold sweat and overwhelming nausea. sensing it wasn't a stomach bug, she told her husband to call 911. >> my husband looked at me and he said, have you lost your mind? i said, maybe. i said, but let's call 911 and see what they say. >> reporter: at just 41 years old, maxine was having a heart attack. >> that was not at all on my radar. not possible. i wasn't a smoker. i had low blood pressure. i didn't have diabetes. >> reporter: she did not have chest pain. a new study shows 42% of women who arrive at the hospital already having a heart attack don't have that classic red flag. and once at the hospital nearly 15% of women die, compared with 10% of men. one reason is that women are more likely to have atypical symptoms. shortness of breath, light headedness, pain in the jaw, neck or arms, nausea, cold sweats and extreme fatigue. those symptoms which are most common in younger women are not always recognized as a serious threat. >> this creates a perfect storm. because women get to the hospital later. they're traditionall