DOCTORS should have increased access to medical records, a coroner's jury said yesterday. The jury returned a verdict of death by natural causes on security guard Chang Chen-ching, 62, who died from heart failure on January 7. Chang collapsed in a car park and was dead on arrival at Queen Elizabeth Hospital. The Coroner's Court heard that a doctor who saw him on several occasions shortly before his death and did not diagnose his heart condition had no access to Chang's medical history. In a rider to its verdict, the jury recommended doctors should try to obtain medical histories when consulted by new patients. Dr Sun Yiu-kwong said Chang saw him in December 1992. He had on various occasions complained of nausea, stomach pain, insomnia and constipation but had not mentioned chest pain. Given the cause of death, chest pain could have been expected, although the court heard it was possible to suffer a heart attack without having shown previous symptoms. Dr Sun said he would have carried out an electrocardiogram if Chang had complained of chest pain. Had that shown anything abnormal, he would have referred him to a specialist. The last time he saw Chang, Dr Sun treated him for insomnia and nausea and advised him to return two days later. Answering a question from Coroner Warner Banks, he said in only a small percentage of cases would medical histories be passed on if a patient changed doctor. A doctor who had previously treated Chang, Dr Gan Mie-fang, said the last time she saw him was on October 30. He had diabetes and she had advised him to lose weight, exercise and not do anything ''heavy''. At no stage had he complained of chest pain.