Kara Kennedy, the oldest child of the late Sen. Edward M. Kennedy, died Sept. 16 after a workout at a health club in Washington. She was 51.

Her brother, Patrick Kennedy, a former congressman from Rhode Island, confirmed the death. Their father died in 2009 at age 77 after being diagnosed with a brain tumor.

Kara Kennedy had survived a previous diagnosis of lung cancer. In 2003, doctors removed a malignant tumor.

Patrick Kennedy said that he thinks her cancer treatment “took quite a toll on her and weakened her physically.”

“Her heart gave out,” he said.

Kara Kennedy was the oldest of his three children, born in 1960 while Edward M. Kennedy was helping his brother, John F. Kennedy, campaign for the presidency. (AP Photo/Steven Senne/AP Photo/Steven Senne)

Kara Kennedy served as a board member of the Edward M. Kennedy Institute for the United States Senate.

A Tufts University graduate, she was a filmmaker and television producer who produced several videos for Very Special Arts, an organization founded by her aunt Jean Kennedy Smith.

She also was a director emerita and national trustee of the John F. Kennedy Library Foundation.

Kara Kennedy 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 was the oldest of three children. She and her brother Edward M. Kennedy Jr. helped run their father’s U.S. Senate campaign in 1988.

In 1990, she married Michael Allen. Besides her husband and brothers, her survivors include two children, Grace and Max, and her mother, Joan Kennedy.

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

In an April article she wrote for the Boston Globe Magazine, Kara Kennedy recalled the lessons her father taught his children.

She wrote of family trips in the summer when the senator would lead his children on explorations of historic battlefields and buildings, trips she said taught her that one person can make a difference.

“What mattered to my father was not the scale of an accomplishment, but that we did our share to make the world better,” she wrote. “That we learned we were part of something larger than ourselves.”