HONOLULU — Former surfing champion Andy Irons had several drugs in his system when he died of a heart attack at age 32 in a Dallas-area hotel room seven months ago.

Irons' family released the results of the autopsy Thursday, which show the three-time world champion from Hawaii died from sudden cardiac arrest due to severe blockage of a main artery. The official autopsy report, prepared by Tarrant County Chief Medical Examiner Dr. Nizam Peerwani, also lists "acute mixed drug ingestion" as a secondary cause, but that is being disputed by the family.

According to the autopsy, Xanax, an anti-anxiety medication, methadone, cocaine and a trace amount of methamphetamine were found in his system.

The family said in a statement that Irons was prescribed Xanax and Zolpidem (Ambien) to treat anxiety and occasional insomnia, a result of bipolar disorder diagnosed at age 18 when he first began "experiencing episodes of manic highs and depressive lows."

"The family believes Andy was in some denial about the severity of his chemical imbalance and tended to blame his mood swings on himself and his own weaknesses, choosing to self-medicate with recreational drugs," the Irons family said in the statement. "Members of his family, close friends, and an industry sponsor intervened over the years to help Andy get clean, but the effort to find balance in his life was certainly complicated by his chemical makeup."

The surfer claimed the world championship in 2002, '03 and '04, and was a four-time winner of the prestigious Vans Triple Crown of Surfing.

Irons, who is revered in Hawaii and was known in the surfing community worldwide for being fearless, humble and a fierce competitor, died Nov. 2 while on a layover while en route home to Kauai from Puerto Rico. He had withdrawn two days earlier from the 2010 Rip Curl Pro Search with flu-like symptoms, been put on an intravenous drip and urged to seek medical attention but decided to return to Hawaii. According to the family, it was the first time he had withdrawn from a competition.

Irons' death cut short a big year for him professionally and personally. He was making a comeback in surfing after spending the previous year away from the sport. He was also looking forward to being a father.

San Antonio forensic pathologist Dr. Vincent Di Maio, who reviewed the autopsy results for the family, called it a "very straightforward case," where Irons died of hardening of the arteries. He said plaque produced severe narrowing, 70 to 80 percent of his anterior descending coronary artery.

"The only unusual aspect of the case is Mr. Irons' age, 32 years old. Deaths due to coronary atherosclerosis usually begin to appear in the late 40's. Individuals such as Mr. Irons have a genetic predisposition to early development of coronary artery disease," Di Maio said.

Irons' grandmother and grand-uncle on his father's side died of congestive heart failure. His widow, Lyndie, recalled that Irons complained of chest pains and occasional intense heartburn for the first time last year.

Contrary to Peerwani's report that drugs were a secondary cause, Di Maio said: "There were no other factors contributing to the death."

The Irons family's attorney in Dallas has sent a letter to Peerwani, questioning his decision to list the drugs as a secondary cause, even when the death was listed as natural.

Peerwani's office didn't return a phone call seeking comment.

"As we are not doctors, we have no choice but to accept that two respected pathologists have come to different conclusions about a secondary contributing cause of death," the family said.

Lyndie Irons insisted her husband was not a meth user, and suggested the substance was present in the cocaine he used.

The autopsy report has been held up for months by a Texas court, which blocked the release in December at the request of Lyndie Irons, who argued the report could tarnish her husband's brand, upon which she and her son are financially dependent. She cited intense news coverage and "innuendo of drug use" surrounding the death. Although the family released the results Thursday, the full report won't be made public until later this month.

The family apologized for the delay and said the injunction was to allow Lyndie, who was then eight months pregnant, "to give birth in peace." Her son is named Andy Axel Irons.

The family said it hopes people remember Irons for his "very full life, which included his intense passion for surfing and the ocean, his astonishing achievements as a world-class athlete, and his devotion to the family and friends.

"Receiving the disturbing news about the cause of death brings back the shock and tremendous grief we first felt upon receiving word that Andy had passed," the family said.

The family was thankful for the outpouring of condolences and support.

"There was so much positivity in Andy's professional and personal life, not least of which was how hard he worked to overcome his challenges," the family said. "For this we remain forever proud of him."

Jaymes Song can be reached at http://twitter.com/JaymesSong