Updated: Autopsy: Cardiac Arrest Killed RB High Senior David Hu

Updated 2:15 p.m. Sunday with details of genetic testing and the removal of the autopsy report at the family's request.

Sudden cardiac arrest, possibly the result of a genetic condition, caused the death of 17-year-old Rancho Bernardo High School senior David Hu in January, according to the teen's autopsy report made available Friday.

No drugs or alcohol were found in the teen's system and there was "no indication of any illicit drug or alcohol use" in his bedroom, the San Diego County Medical Examiner's report said.

Hu, who was slated to be valedictorian and had , was found unresponsive  in his bed at home on the morning of January 5. Hu's 13-year-old brother, Kevin, woke up when he heard David yelling just before 5 a.m. After looking into his brother's room and hearing him moaning, Kevin got his parents who came and found the teen's lips blue and white, the report said.

Hu's father began CPR and his brother called 911. Paramedics arrived eight minutes later and found the teen in ventricular fibrillation—when the heart's rhythm becomes erratic and it becomes difficult for the heart to pump blood. Paramedics continued life-saving efforts before transferring Hu to Pomerado Hospital, where he was pronounced dead at 6:47 a.m. after continued efforts there to revive him failed.

According to the autopsy report, Hu had an "essentially unremarkable" medical history, no history of drug or alcohol use and no indications that he was considering suicide. He had been tired lately, but had not had any significant illnesses since coming down with the flu a year prior. Two months before his death, Hu stayed home from school for one day with a cold.

The report suggested that Hu's sudden cardiac arrhythmia (irregular heartbeat) may have been caused by the genetic disorder Brugada syndrome, but genetic testing did not find any of the mutations associated with the syndrome. However, the report also noted that the test only detects 80 percent of the mutations associated with the syndrome.

The teen's death has officially been classified as due to natural causes.

Editor's Note: The autopsy report has been removed at the family's request.