A newborn's heart fully recovered after a heart attack

Mouse studies had shown that a newborn mouse heart can regenerate completely if injured in its first week of life, a window that closes fast. Whether a human newborn had any of that same capacity was still an open question.

Doctors in Innsbruck, Austria documented a newborn who suffered a severe heart attack from a blocked coronary artery, with imaging and blood markers confirming massive damage to her heart muscle. Within weeks the child's heart function returned to normal and stayed normal on long-term follow-up.

It is a single documented case, not a trial, so it cannot prove how common this capacity is or how long the window lasts in people. But it lined up with the mouse data closely enough that researchers now treat early infancy as a plausible, narrow opportunity for the human heart to repair itself before that ability fades.

A newborn heart, fully recovered.