A drug used to treat erectile dysfunction has been found by University of Manchester scientists to slow or even reverse the progression of heart failure in sheep.

The British Heart Foundation funded study is a breakthrough in the treatment for the disease in which five year survival rates are lower than most common cancers.

The study of Tadalafil – which is in the same class as Viagra – proves that the drug is biologically effective as a treatment for heart failure in sheep.

However, lead author Professor Andrew Trafford argues the effect is likely to also be shown in humans. The study is published in the journal Scientific Reports.

Heart failure is a devastating condition, occurring when the heart is too weak to pump enough blood to meet the body's needs.

It also causes a build-up of fluid that backs up into the lungs, resulting in breathlessness as well as fluid retention, resulting in swelling of different parts of the body.

Most current treatments are ineffective.

“This discovery is an important advance in a devastating condition which causes misery for thousands of people across the UK and beyond,” said Professor Trafford.

“We do have limited evidence from human trials and epidemiological studies that show Tadalafil can be effective in treating heart failure.

“This study provides further confirmation, adds mechanistic details and demonstrates that Tadalafil could now be a possible therapy for heart failure.

“It’s entirely possible that some patients taking it for erectile dysfunction have also unwittingly enjoyed a protective effect on their heart.”

Sheep were used by the team as the physiology of their hearts is similar to human hearts.

When the animals had heart failure – induced by pace makers – which was sufficiently advanced to need treatment, the team administered the drug. Within a short period the progressive worsening of the heart failure was stopped and, importantly, the drug reversed the effects of heart failure.​