WASHINGTON - AUGUST 12, 2009: U.S. President Barack Obama presents the Medal of Freedom to Kara Kennedy on behalf of her father, Sen. Edward Kennedy (D-MA), during a ceremony in the East Room of the White House August 12, 2009 in Washington, DC. Obama presented the medal, the highest civilian honor in the United States, to 16 recipients during the ceremony. (Photo by Chip Somodevilla/Getty Images)

BOSTON (CBS/AP) – Kara Kennedy, the only daughter of the late Senator Edward Kennedy, has died.

The 51-year-old Kennedy passed away after suffering a heart attack Friday evening following her daily workout at a Washington-area health club.

Kennedy was a member of the Sport & Health fitness center, though spokeswoman Nancy Terry declined to release further details about the incident, citing member privacy.

Her ex-husband, Michael Allen, said she frequently visited the club and went swimming every day if she could. He said details about her death would be released by The Edward M. Kennedy Institute for the United States Senate. He said funeral arrangements are being made.

“Insofar as I’m concerned her legacy is one of courage and grit and determination in the face of her own illness and in the face of many family tragedies and limitless, absolutely limitless, devotion to our children,” he said.

WBZ-TV’s Paul Burton reports.

Her brother Patrick Kennedy told The Associated Press on Saturday that “she’s with dad.” Their father, Senator Ted. Kennedy died in 2009.

Kara was a lung cancer survivor and her cancer had been in remission since 2003.

Patrick Kennedy says he thinks his sister’s cancer treatment “took quite a toll on her and weakened her physically.” He says “her heart gave out.”

He also says his sister loved to exercise.

WBZ NewsRadio 1030’s Kim Tunnicliffe reports https://boston.cbslocal.com/wp-content/uploads/sites/3859903/2011/09/tunnicliffe-kara-kennedy-w1.mp3

The Edward M. Kennedy Institute for the United States Senate issued a statement Saturday on Kara’s death.

“Kara was a warm and caring person. Her children were the light and joy of her life,” it read. “Her magnificent strength in her successful battle with lung cancer was a quiet inspiration to all us and provided her family and fellow patients with hope. Kara was loved and cherished by the entire Kennedy family… We will all greatly miss Kara’s energy and commitment to the Institute and her generous spirit.”

In a statement, Massachusetts Senator Scott Brown offered his and his wife’s prayers and sympathies to the Kennedy family.

“Kara proudly carried on her family’s commitment to public service through her volunteer and charitable work, and was a devoted mother to her two children,” Brown’s statement read in part.

Kara Kennedy, a graduate of Tufts University, was the oldest of three children. She was born in 1960 as her father campaigned for his brother, John F. Kennedy, during the presidential primaries.

The late senator wrote in his 2009 memoir, “True Compass,” that “I had never seen a more beautiful baby, nor been happier in my life.”

She and her brother Edward Kennedy Jr. helped run their father’s U.S. Senate campaign in 1988.

She was diagnosed with lung cancer in 2002 and was given a grim prognosis by doctors, her father wrote.

In her father’s book, Edward Kennedy recalled her operation, along with her aggressive chemotherapy and radiation treatments.

“Kara responded to my exhortations to have faith in herself,” he wrote. “Today, nearly seven years later as I write this, Kara is a healthy, vibrant, active mother of two who is flourishing.”

In 2009, shortly before his death, Edward Kennedy was awarded the Presidential Medal of Freedom by Barack Obama. Kara Kennedy accepted the award on behalf of her father.

Kara was a filmmaker and television producer. She produced numerous videos and materials for Very Special Arts, an organization founded by her aunt Jean Kennedy Smith.

Kara also served on the National Advisory Board of the National Organization on Fetal Alcohol Syndrome and as a Director Emerita and National Trustee of the John F. Kennedy Library Foundation.

She also worked as a producer at Evening Magazine, a show produced at WBZ-TV between 1977 and 1990.

Kara leaves behind two teenage children, Grace and Max, along with her mother Joan; her brothers Ted, Jr. and Patrick; her step mother Victoria Reggie Kennedy; and her stepbrother and sister, Curran and Caroline Raclin.

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