Bystanders who spot a woman suffering from cardiac arrest are less likely to resuscitate her than those who witness a man suffering from a similar episode, according to a new study.

The report, which was published Thursday in the European Heart Journal, raises serious questions about how the public perceives cardiac arrests, which are more fatal among women than men.

A cardiac arrest – not to be confused with a heart attack – is when a person’s heart goes into a chaotic electrical rhythm and is no longer able to pump. About 25 per cent of cardiac arrests are caused by heart attacks, which happen when blood supply to part of the heart becomes blocked, often by a clot in a major blood vessel.

Women who suffer cardiac arrests are about half as likely to survive as men.

The reason that bystanders may be slow to resuscitate a woman could be that women are less likely to present obvious symptoms, said Dr. Paula Harvey, chief of medicine at Women’s College Hospital.

“Men are more likely to present with what we sort of refer to as the Hollywood heart attack: crushing central chest pain, clutching at the chest, sweating,” she told CTV News Channel. “A woman may present like that, but she can also have other symptoms that we refer to as atypical symptoms … her predominant symptom could in fact be dizziness or profound sweating or profound fatigue.”

A lack of awareness could play a factor.

“It’s also possible that the people around a woman may think that she has had a faint rather than a more catastrophic event such as a cardiac arrest that perhaps they might identify more as being a problem in men than in women,” Harvey said.

The study looked at 5,717 women who suffered out-of-hospital cardiac arrests and were treated by Emergency Medical Services. The report found that 67.9 per cent of those women had an attempted rescucittaion by bystanders, versus 72.7 per cent of men.

The report also found that, even when resuscitation was attempted by EMS, women benefitted less than men.

Biology may also play an important role. The report found that women were more likely to experience a flat-line heart rhythm, which is “not really possible” to shock a patient out of, Harvey said.

“We know that generally there is a period of time between the chaotic rhythm and deterioration into this flat line. And it appears that women may deteriorate into the flat-line type of circumstance … more quickly than men.”

To close the survival gap between men and women, researchers suggested further research look into biological reasons for lower survival rates and how pre-hospital treatments can be changed.

Harvey said educating people about cardiac arrests and encouraging them not to be afraid of using a defibrillator are important steps.

“It can affect people across the lifespan, so we need to be educating the public on what we mean when we refer to a cardiac arrest so that the public can help us improve the survival of these patients, because we know time is completely of the essence.”