Women are less likely to be resuscitated and survive a cardiac arrest than men, a new study has found.
The research, published in the European Heart Journal, found women and men received unequal treatment when suffering a cardiac arrest.
It found women who have a cardiac arrest outside the hospital setting are less likely to receive resuscitation from passersby and more likely to die than men.
The disparity in treatment they received in the community was found to be partly to do with the fact that people did not recognise that women who had collapsed were having a cardiac arrest – prompting delays in calling the emergency services and delays in delivering resuscitation treatment.
Cardiac arrest takes place when the heart goes into an irregular rhythm and then stops beating entirely. It is different from a heart attack.
Dr Hanno Tan, a cardiologist based at the University of Amsterdam, said: “We found that the worse outcome in women is largely attributable to the fact that women had about half the chance of having a shockable initial rhythm compared to men.”
Dr Tan, who led the research, and his team analysed data from all resuscitation attempts made by emergency services between 2006 to 2012 in one province in The Netherlands. They identified 5,717 out-of-hospital cardiac arrests treated during this period – 28 per cent of which occurred in women.
They found women were less likely than men to receive a resuscitation attempt by a bystander – 68 per cent rather than 73 per cent. The figure was virtually the same even when someone witnessed the collapse.
Survival from the time of the cardiac arrest to admission to hospital was lower in women – 34 per cent versus 37 per cent. Women were less likely to survive from admission to discharge – 37 per cent rather than 55 per cent.
Overall, the chances of women surviving to be released from hospital was around half that of men. Researchers consider this is largely explained by the lower rate of shockable initial rhythm in women – 33 per cent versus 52 per cent – and found several reasons that might explain this difference.
Shockable initial rhythm is the heart rhythm recorded when someone with cardiac arrest is connected to an electrocardiogram machine. It is highly fast – often more than 300 beats a minute – and chaotic. Death takes place within minutes unless the heart can be shocked back to a normal rhythm by means of an electrical current from a defibrillator.
Dr Tan said that even when they adjusted their findings to take account of pre-existing diseases and factors relating to the way in which resuscitation was provided by professionals – for example how long it took for the ambulance to arrive – they still found women were half as likely as men to have shockable initial rhythm.
“This suggests that the lower proportion of women with shockable initial rhythm is not fully explained by women being more likely to have pre-existing diseases or by different resuscitation factors, and that other, as yet undiscovered, factors also play a role,” he added. “However, when we looked only at cardiac arrest victims who did have a shockable initial rhythm, we found there was no difference in overall survival rates between men and women.”
Researchers said a potential reason why fewer women have shockable initial rhythm by the time the emergency services get to them may be because fewer women than men tended to have a cardiac arrest when there were other people around to see it happen. They noted this could be linked to there being more elderly women living on their own than men and because the symptoms of a heart attack – one of the most common causes of cardiac arrest – might not be recognised so rapidly in women.
Dr Tan said: “People may be less aware that cardiac arrest can occur as often in women as in men, and the women themselves may not recognise the urgency of their symptoms. Women may have symptoms of an impending heart attack that are less easy to interpret, such as fatigue, fainting, vomiting and neck or jaw pain, whereas men are more likely to report typical complaints such as chest pain.”
He added: “As cardiac arrests occur most often outside the hospital setting in the general population, much can probably be gained by raising awareness in society that cardiac arrest is as common in women as in men but may have different symptoms. Given the short window available to save the life of the patient, every minute in this early phase counts; help, if only a call to the emergency number by a layperson, is crucial. So, raising awareness through public campaigns could make a big impact on women’s survival.”
Researchers argued there was a need for a range of measures to address the issue of survival differences between men and women. This spanned from public awareness campaigns about heart attack and cardiac arrest in women to the reform of health care systems so as to provide faster resuscitation to women – especially those who live alone. They suggested the idea of wearable devices that monitor heart rate and circulation which are able to send alerts to monitoring systems.