Former Rays pitcher Joe Kennedy died of natural causes related to heart disease, Hillsborough County Medical Examiner Dr. Vernard Adams said Tuesday.

Kennedy, 28, collapsed and died at his in-laws' home in Lithia on Nov. 23, during a Thanksgiving weekend visit. He died, Adams said, as a result of two relatively common problems with his heart - hypertensive heart disease and myxoid valvular disease - that are somewhat uncommon for people his age.

"There were two reasons he had abnormal electrical rhythms that led to his heart stop pumping,'' Adams said. "The combination of his age and the two diseases is somewhat unusual.''

Though a final toxicology report has not been completed, Adams said he reviewed enough of the results to determine the cause of Kennedy's death. "He did not have a drug intoxication, he died by natural disease,'' Adams said.

Kennedy had been with Oakland much of the last three seasons and A's officials told the San Francisco Chronicle they had done numerous tests on Kennedy because of a family history of heart disease, but according to team physician Dr. Allan Pont "there were no abnormalities to suggest anything wrong with his heart.''

Adams said though Kennedy had some high blood pressure readings, "he was never given the label hypertensive,'' and that an echocardiogram was normal.

Hypertensive heart disease can lead to a thickening of the heart wall and elevated blood pressure. Myxoid valvular disease can lead to incompetence of the valve on the left side of the heart, but Adams said in Kennedy's case it resulted in electrical instability.

Kennedy was an eighth-round pick in the 1998 draft by the Rays and came up through the system, making his big-league debut in 2001 and was their opening day starter in 2003. He struggled to a 3-12 record that season and the Rays traded him after the season to Colorado as part of a three-team deal that brought Mark Hendrickson to Tampa Bay.

He went on to pitch for the A's and Jays, compiling a 43-61 career record with 4.79 ERA in 222 games.