Nearly half of all women suffering from cardiac arrest are given insufficient treatment, since heart failure in them -- unlike in men -- is not caused by a heart attack, but by untreated high blood pressure, a new study reveals.
According to the study, published in Nature Medicine, only 50 per cent of the heart failure cases among women are caused by having a heart attack, which can be treated with modern methods.
However, the researchers, including those from the University of Bergen in Norway, said the cause for heart failure in the other 50 per cent of women is generally related to having untreated high blood pressure levels over time, leading to progressive stiffening of the heart.
There is no effective treatment for this kind of heart failure yet, the study noted.
"Men and women have different biologies and this results in different types of the same heart diseases. It is about time to recognise these differences," said study co-author Eva Gerdts from the University of Bergen.
As part of the study, the researchers compared common risk factors for heart disease, and how these affect men and women differently.
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They focused on the sex differences in the effect of obesity, high blood pressure, and diabetes.
One of the factors assessed by the researchers was the differential influence of obesity on heart failure between men and women.
They said according to the World Health Organization (WHO) 11 per cent of women and 15 per cent men are obese globally.
"If we see this from a life span perspective, we can see that obesity increases with age, and that this trend is greater for women than men. Obesity increases the risk of having high blood pressure by a factor of three. This, in turn, increases the risk of heart disease," Gerdts explained.
She said obesity also increases the risk of diabetes, with women facing a much higher relative risk of heart complications and death from the condition than men.
"We know that women with diabetes 2 are usually obese and some of this fat is stored in the heart, which makes it more vulnerable for disease," Gerdts said.
When it comes to heart disease, many of the differences between women and men are connected to the sex hormone, oestrogen, she explained.
According to the study, the hormone prevents the formation of connective tissue in the heart, which makes it harder for the organ to pump blood.
However, in men the effects are the opposite, the researchers noted.
"We see that obese men store oestrogen in their fat cells in the abdomen, which has a bad effect on the heart," Gerdts said.
After menopause, she added, women lose the oestrogen advantage.
During this phase, she said, women's arteries becomes stiffer and more vulnerable for disease.
"We think that this is part of the explanation for why high blood pressure seems to indicate higher risk of heart disease amongst women," the University of Bergen scientist said.
Additionally, Gerdts said, smoking is also a risk factor for women.
"Many women start smoking to reduce their appetite and to control their weight. However, this is not a good choice from a health perspective," she added.
"Heart disease remains among the most common cause of death and reduced quality of life in women. Medically speaking, we still do not know what the best treatment for heart- attack or -failure is in many women. It is an unacceptable situation," Gerdts said.