An autopsy shows that the 61-year-old woman whose body was found in the restroom of a Delta Air Lines plane died from a heart abnormality, officials said.

Georgia's Chief Medical Examiner Dr. Kris Sperry says a pre-existing heart condition is responsible for the Michaele O'Neil Carnahan's sudden, natural death. He says Carnahan was undergoing evaluation by her personal physician for suspected heart problems.

The specific nature of the heart disease will be disclosed later following further examination of the Ventura, Calif., woman's heart.

Carnahan's body was found in the restroom shortly before the flight from Los Angeles to Atlanta landed Wednesday morning.