ZHENGZHOU, Feb. 1 (Xinhua) -- At 2:19 a.m., Cheng Zhaoyun completes a cardiac surgery. Although he has been standing in the operating room for more than 10 hours, he habitually takes out a sketch book and begins drawing a heart.

Before long a complete coronary artery map is vividly displayed on the page, with exact sizes of blood vessels and sections of the heart, date of the surgery as well as a brief patient profile.

For the past 18 years, Cheng, team leader of the cardiac surgery department at Henan Provincial People's Hospital in central China, has sketched the hearts of over 3,900 patients.

In contrast to computer graphics, the sketches highlight the more critical and detailed parts of each patient's heart, which makes it easier for Cheng's students to grasp difficulties faced in operations.

Back in 1997, the then 33-year-old heart specialist was sent to St Vincent's Hospital in Melbourne for clinical study. He often skipped meals so that he could have more time for performing operations and patient observation. During his stay, he took over 1,000 pages of medical notes in English.

In January 2000, he completed the first coronary bypass operation in Henan. Before the operation, he carefully drew the patient's heart and lesion location, and over a dozen pages of operation details and points for attention.

He has since developed a habit of sketching each patient's heart based on their coronary angiography and ultrasound. Once the operation is completed, he records as many details as possible on operating procedures and new findings during the operation on the sketch.

"Members of the surgical team can see quite clearly the patient's lesion and physical conditions from a sketch like this, which facilitates a smooth operation and targeted follow-up," said Cheng.

As one of China's most populous provinces, Henan has a large number of patients in need of cardiac surgeries. Over the past three years, Cheng's team ranked in the top 10 in terms of number or operations and the top three in surgical quality control in China.

In Cheng's office, he carefully files all the over 3,900 sketches he has completed since 2000, a valuable database on coronary artery bypass cases.

"As the pile of sketches grows thicker, I become more confident about the treatment of my patients," he said.