Queen Mary Hospital on Wednesday made an urgent appeal for heart donors to save the life of a 48-year-old man who suffers from ischemic cardiomyopathy, a type of heart disease affecting patients when their heart muscle doesn't receive enough blood flow.

Doctors said Kwok Ho-wing's heart is severely damaged due to a blockage in his coronary artery, and his heart function is at less than 20 percent.

Kwok has been experiencing breathing difficulties and chest pains since December.

He has had no prior major health problems.

Kwok, who works as a machinery repairman, is the breadwinner of the family and has a 13-year-old daughter.

Consultant Doctor Oswald Lee said his heart is unable to pump blood effectively without the help of machines, which could cause complications nevertheless.

“Because of the mechanical circulation support machines... these machines are associated with a lot of complications. Although they are essential at this moment to maintain his life, a lot of complications can happen at any time," he said.

"If any of these complications happen, that could cost his life very rapidly.

“But if you have to put a time frame, I would say within two to three weeks.”

Donors should have O positive blood type and be similar in size to Kwok, who weighs 57kg and is 168cm tall.

“Most of the time, the donor should not have any prior cardiac disease or heart disease. We also need to assess the function of the donor's heart,” Consultant Doctor K L Wong said.

According to data from the Hospital Authority, there are currently 76 patients on the waiting list for heart transplant and only eight transplants were conducted last year.