Elvis Presley died in 1977, aged 42, after becoming addicted to prescription drugs and junk food. But a new investigation has suggested he was suffering from hypertropic cardiomyopathy, which causes heart failure by weakening the organ's muscle, Classic Rock reports.
Dr. Stephen Kingsmore, a specialist based in Kansas City, examined DNA extracted from a strand of Presley's hair which had been kept by his barber.
He found evidence of variations in the genes known to cause the heart condition, and others that may have contributed to the weight, headache and eyesight problems Elvis suffered towards the end of his life.
Kingsmore says: "There had been so much speculation about cause of death and so much ill spoken of his lifestyle. We had this intriguing finding that, possibly, Elvis had a medical illness.
"All the stuff about how he killed himself with his lifestyle might have been very unfair."
Full results of the investigation will be revealed in the first episode of the Channel 4 series Dead Famous DNA, broadcast tonight (Wednesday) at 9pm.