Yet — if indeed a stroke was the primary cause of death, as her son, Todd Fisher, has said — a heart squeezed by the sudden loss of a beloved daughter could have contributed. The stunned organ, especially in a person who might have had any of the underlying cardiovascular infirmities of aging, could increase the likelihood of a clot forming and moving to the brain.

In a 2005 paper in The New England Journal of Medicine, doctors at Johns Hopkins University School of Medicine reviewed cases of 18 women and one man who landed in coronary care units in Baltimore, between 1999 and 2003, with chest pains and no signs of classic heart attack on exam. Most were older, but one was 27 and another 32. The doctors, led by Dr. Ilan Wittstein, nicknamed the condition broken-heart syndrome and noted that it occurred not only after grief but after any sudden stress. All of the patients survived.

“We had people who’d been held up at gunpoint, who’d been up in front of a group to speak, who were severely claustrophobic and in an M.R.I. scanner, who were angry and in heated arguments,” Dr. Wittstein said in an interview.

Dr. Wittstein said that at the time the paper appeared virtually the only mentions of the syndrome were in Japanese medical literature. Now, he said, thousands of cases have been reported, and about 90 percent of them are women in middle age or older. One possible reason, he said, is that estrogen protects the heart’s smaller vessels — those most affected by stress hormones — and estrogen levels drop with age.

There have been cases of well-known couples dying in close succession. The country stars Johnny and June Cash died within months of each other, after a long marriage. The former football star Doug Flutie’s parents died on the same day, both of heart attacks. To some medical experts, what Ms. Reynolds experienced is one of the greatest traumas of all.

“No one wants to change the order of nature, that is the first thing I thought when I heard,” said Dr. Victor Fornari, a psychiatrist at Northwell Health on Long Island. “A parent outliving a child — it’s one of the most unspeakable things there is.”