Over the past two years, Zhang Weida has traveled several times to remote Tibetan counties and Lhasa, the region's capital, to give free medical checks to about 20,000 children. Provided to China Daily

For doctor Zhang Weida, the Tibet autonomous region is not only a holy land filled with blue skies and vast grasslands, but also a high-risk place for congenital heart disease.

Over the past two years, Zhang, director of the cardiothoracic surgery department of the General Hospital of Guangzhou Military Command of the People's Liberation Army, has traveled several times to remote Tibetan counties and Lhasa, the region's capital, to give free medical checks to about 20,000 children.

"The region is highly vulnerable to congenital heart disease due to its high altitude," Zhang says.

On his first trip to Tibet in July, 2012, Zhang spent five days in Nagqu, Baingoin and Nyima and gave free checks to 639 children suffering from the disease.

He decided to bring some 70 children diagnosed with the disease to Guangzhou to give them free surgery.

"Congenital heart disease can be fatal if untreated. But most children can be totally healthy after the surgery," Zhang says.

After the first trip, Zhang, along with his team members, successfully performed free surgery on 126 Tibetan children suffering from the disease, sources with Guangzhou hospital said.

"I felt very happy and satisfied when their lives returned to normal after the surgery," Zhang says.

Zhang was speaking after a successful visit by a group of 23 Tibetan children who went to Guangzhou to receive free surgery on March 21.