The team from Columbia University used stem cells to grow it.
Scientists successfully grow a human heart muscle for the first time using stem cells, the Daily Mail reported.
It took just four weeks to grow a fully functioning heart. Normally it takes a baby nine months to develop a heart in the womb.
The team from Columbia University used stem cells, "which were easier to manipulate" and they believed it would respond better to stimulation in order to accelerate growth. Experts call stem cell transplants a 'game changer' for people suffering from multiple sclerosis, disease of the brain and spinal cord.
This development will be very useful for medical research to be able to further study human physiology.
Researchers will be able to more clearly test treatments for health issues like heart failure on a heart grown in a lab that can mimic diseases in an adult.
"The resulting engineered tissue is truly unprecedented in its similarity to functioning human tissue," Seila Selimovic, director of the NIBIB (National Institute of Biomedical Imaging and Bioengineering) Tissue Chips program, within the National Institutes of Health that funded this research, told the Daily Mail.
Adding, "The ability to develop mature cardiac tissue in such a short time is an important step in moving us closer to having reliable human tissue models for drug testing."