Heart failure has historically been irreversible, but a new study suggests that could change. At the University of Utah, scientists used a new gene therapy that reversed heart failure in animals.

The therapy increases the amount of blood the heart can pump and dramatically improves survival, in what a paper describing the results calls “an unprecedented recovery of cardiac function.”

New research shows the gene therapy didn’t just prevent heart failure from worsening in four lab pigs, but actually prompted hearts to repair and grow stronger. “Even though the animals are still facing stress on the heart to induce heart failure,

In a new study, failing hearts nearly returned to full function in laboratory pigs after they received an experimental gene therapy.