A pregnancy hormone could provide the first breakthrough in 20 years for treating acute heart failure.
Doctors found that Serelaxin, a synthetic version of the hormone relaxin, can slash the death rate for people with the condition.
Heart failure, which affects around 900,000 people in the UK, means the heart can no longer pump enough blood around the body.
The body tries to compensate by increasing the heart rate and narrowing blood vessels to push up blood pressure.
But in the long term these put the heart under greater strain.
As the heart becomes less efficient, blood can pool in vessels around the lungs; the pressure builds up and fluid leaks from the blood vessels into the tiny air sacs, causing breathlessness, tiredness and swelling.
Current medications such as beta blockers and ACE inhibitors reduce stress on the heart by, for example, lowering blood pressure.
This helps alleviate symptoms but does not help the underlying condition, which can progress to acute heart failure.
Here the lungs are so filled with fluid the patient finds it difficult to breathe at all, and feels as though they are drowning.
It is a life-threatening emergency which requires immediate hospital treatment — around 30 per cent of patients hospitalised after an episode of acute heart failure die within a year, making it more deadly than a heart attack.
The new treatment is based on relaxin — levels of this rise dramatically during pregnancy in order to reduce strain on the mother’s heart.
The amount of blood circulating in a woman’s body increases by between 20-50 per cent in order to transport oxygen to the foetus via the placenta.
However, this means her heart needs to work 30 per cent harder.
Relaxin helps by opening up the blood vessels and reducing blood pressure, taking excess strain off the heart; relaxin also boosts kidney function, removing waste products from the blood.
A six-month international study found that Serelaxin reduced heart failure death rates by a third (37 per cent) compared to conventional treatments such as ACE inhibitors.
Serelaxin appears to help the heart itself, unlike existing treatments which simply improve symptoms, says Martin Cowie, professor of cardiology at Imperial College London.
He was not involved in the research but believes the new drug could mark ‘a seismic shift’ in the treatment of acute heart failure.
‘The current medications dampen the body’s own responses to the heart not pumping properly (such as increased blood pressure) whereas Serelaxin works in synch with the body, he says.
‘We are not entirely clear how it works but it helps take the load off the heart. It also helps prevent further damage to the heart and kidneys, and this translates into longer-term benefit.’
The drug, which was developed by Novartis, is given in a drip for the first 48 hours after a patient is admitted with heart failure — when the risk of other organs failing is greatest, because of the poor blood supply.
More studies are being conducted on the drug, which could be approved as early as next year.