The tiny human heart was still beating as of 9 am Thursday, at a rate of 20 per second, according to doctors with the procreation center lab of the Shenyang Women and Infants' Hospital in Shenyang, capital of Liaoning Province.

To date, there have been no similar cases at home or abroad, doctors said.

Qu Wenyu, president of the hospital, says that the heart is growing well and taking on the shape and structure of an adult heart. "The ventricle and atrium of the miniature heart are beating synchronously," Qu said.

The ventricle of the tiny heart initially beat between 18 and 22 times, and the atrium, 60 to 80 times per second, according to Qu, adding that he and his colleagues are still mystified by the slower heartbeat.

"Compared to a normally-developed embryonic human heart, this heart is much smaller in size and lacks the perfect structure and functions of a normal embryonic human heart," said doctor Wang Tong, who is in charge of the research on the heart.

The small heart came from a 52-day old embryo, the result of an abortion. On June 5, Wang removed the heart from the embryo and placed it into a culture dish in the procreation lab.

Wang said when he arrived at the lab on the morning of June 6, he was thrilled to find the heart beating strongly, and he observed, with the help of a microscope, that the cells of the heart were breaking up.

"This showed that the heart was growing," Wang said excitedly.

Prior to culturing of this human heart, research of this type in China was conducted on peacocks, fish and mice, according to scientific documents provided by the Liaoning Provincial Science and Technology Information Research Institute.

Significantly, there is no record of the survival of in vitro embryonic human hearts anywhere in the world thus far, according to the research institute.

Wang said that his lab has been conducting research on protogonocytes in the genital ridge, hoping to obtain stem cells to enable cloning of human body organs and parts such as lungs, livers, eyes, hands and stomachs.

Through this research, he hopes that it will some day be much easier for doctors to treat patients, just as they would repair a motor vehicle -- by simply replacing a part, Wang said.

Qu Wenyu said that the survival of the human heart for such a long period indicates, at a minimum, a breakthrough in culture technology, which can help to unveil the secrets of the development of human beings from a germ cell.

Doctors with the lab say that the survival of the two human hearts is also significant for the study of clone technology and pharmacology.

(Xinhua News Agency July 11, 2003)