BEIJING, May 5 (Xinhua) -- China may have five to eight million pulmonary hypertension (PH) patients, but only 10,000 to 20,000 have been treated, said a PH expert in Beijing Saturday.

Professor Jing Zhicheng, a PH expert from Fuwai Hospital and Chinese Academy of Medical Sciences, said that most of Chinese PH patients were misdiagnosed or undiagnosed.

Patients suffering from pulmonary hypertension have higher blood pressure in the lungs, so the heart has to work very hard to pump blood into the lungs and becomes more and more fatigued.

Every year on May 5, or World PH Day, PH organizations, patients, doctors and experts around the world hold activities to raise awareness of this serious disease.

PH patients usually experience symptoms such as shortness of breath, dizziness and fatigue, which mirror some other common illnesses, such as asthma or left-heart failure, said Jing.