Ann Brunner was at home with her best friend when a sudden, wrenching pain took her breath away. Her chest felt like it was being crushed by a sumo wrestler, the squeeze migrating to her shoulders and back. She fell into a chair and her friend told her that her face was ashen. "I felt like the plug on my life had been pulled," Brunner recalls.

Later, in the emergency room at Einstein Medical Center Philadelphia, an abnormal electrocardiogram and elevated blood enzymes confirmed what Brunner, a nurse for 34 years, already suspected. She was in the midst of a severe heart attack.

Only, as it turned out, she wasn't.

Brunner was the victim of a condition most of us know little about. Its symptoms mimic those of a heart attack, but they are not caused by blood clots or clogged arteries. The culprits are stress and anxiety. Its official name is tako-tsubo cardiomyopathy. Doctors have labeled it "broken heart syndrome."

The incidence of this mystifying condition is climbing and no one is certain why. But cardiologist Ilan S. Wittstein, whose breakthrough study of 19 patients was published in 2005, suspects that part of the reason is doctors' new-found ability to diagnose it.

"Until then," says Wittstein, assistant professor at the Heart Institute of the Johns Hopkins University School of Medicine, "broken heart syndrome was an obscure condition, largely unrecognized in this country. These cases would have been considered heart attack or heart failure, and patients would have been treated accordingly."

His widely referenced study, published in the New England Journal of Medicine, catapulted the condition from near oblivion to one now easily identified once the patient gets past the emergency room and into the catheterization lab.

Typically, it is sudden emotional stress — a telephone call that brings the news of a best friend's death, a holdup at gunpoint, even the shock from a surprise party — that can "break your heart," precipitating the symptoms that are associated with myocardial infarction. The death of a spouse, especially after a long marriage, or a shattered romance top the list of instigators.

Brunner remembers she was entangled in a fiery argument with her friend's teenage son when her chest agony started.

"It was a difficult time for me," she says. "There was a lot of pent-up stuff and I had had it. I can't remember ever being that enraged."

"This was not a condition we learned about in medical school," says Perry J. Weinstock, chief of cardiology at Cooper University Hospital. "When we saw a patient with these symptoms, we thought it was a heart attack, which we attributed to spasm of an artery. The difference was these folks got better quickly and we would congratulate ourselves for our treatment. In retrospect, our treatment probably had nothing to do with it."

Today, the condition can be diagnosed easily through heart angiography. Taking sophisticated images of the heart enables physicians to rule out heart attack and reveal the "broken heart."

The giveaway is a heart with a curious shape, one that looks like an octopus trapping pot, which has a narrow neck and wide base where an octopus can climb in, but not leave. Japanese doctors identified the condition in the early '90s and named it tako-tsubo, referring to the octopus pot.

"In this country," Wittstein says, "a more apt description might be that of a boxing glove with the strings pulled tight. It was a shape of the heart we had never seen before."

Victims of "broken heart" syndrome learn that their condition, while serious, will probably not recur and that they will likely experience a full recovery within days or at most months. They "breathe a sigh of relief," says D. Lynn Morris, Brunner's cardiologist and director of Einstein's Institute for Heart and Vascular Health. Meanwhile, they are treated aggressively, as though they had had full-blown heart attacks.

If the heart is not squeezing well enough to send blood through the body, an intra-aortic balloon pump might be inserted through a leg artery. If the patient is having trouble breathing, she may need a respirator. If needed, medication is given for high cholesterol and high or low blood pressure.

Once released from the hospital, some continue to take medication similar to those prescribed for heart patients. All are urged to eat healthy diets, stop smoking, and start exercising.

At first, "broken heart" syndrome was looked at skeptically in the medical world. Could emotional stress cause such severe physical symptoms?

But psychiatrist Neill Epperson is not surprised. "We know that many medical problems — asthma, autoimmune diseases, depression, gastro upset — can be caused by stress," says Epperson, who is director of the University of Pennsylvania's Center for Women's Behavioral Wellness. "So why wouldn't something like a heartbreaking loss 'break' your heart?"

Morris, chairman of Einstein's division of cardiovascular diseases, says there was an increase in the syndrome in New York after the attacks of Sept. 11, 2001. And there was a "blip," he says, in Paris when the French lost the World Cup to the Italians in 2006.

Still, there are more questions than answers, and research on the intriguing malady continues. In the first nationwide study, Abhishek Deshmukh, a heart specialist with the University of Arkansas, studied 6,229 cases in a thousand hospitals during 2007. He found that women seemed 7.5 times more likely to experience "broken hearts." It is the only cardiac condition with such a high preponderance among females.

Carol Newman, a Washington marketing executive in her early 50s, was dealing with a "ton of pressure." She was working 60 hours a week, absorbing the workload of a sick colleague, driving 40 minutes each way to look after her mother who was struggling with Alzheimer's disease, trying to stay available to her teenage daughter and son, and surviving on a couple of hours of sleep a night.

One afternoon as she was having coffee with a friend, she became "impossibly emotional," stopped speaking in the middle of a word, turned pale, felt intense chest pain, and thought she would faint. Her angiogram, taken the next morning, showed arteries that were "as squeaky clean as a 19-year-old."

Her diagnosis: tako-tsubo. "My friend and I were having an emotional conversation about work … and something she said threw me over the edge," Newman says. "I think the trigger was insignificant. I was just so overwrought generally that a little bit of emotion got me totally agitated."

Wittstein calls tako-tsubo "a head-scratcher." Why does the condition overwhelmingly affect postmenopausal women? Is there a genetic predisposition? Are certain personality types at greater risk? Why is it that recovery comes so quickly and that there is little likelihood, maybe a 10 percent chance, of a recurrence? He is collaborating on an Italian study of 80 "broken heart" patients and 80 controls that may unravel the mystery.

Meanwhile, a theory is that hormones figure significantly. A sudden shock causes a rapid elevation of catecholamines that rush to the heart, affecting blood flow and temporarily stunning the heart muscle.

In premenopausal women, estrogen protects against such shocks, because it relaxes and dilates blood vessels, allowing good blood flow to the heart. As women age and estrogen levels plummet, they become candidates for tako-tsubo. The estrogen theory may explain, too, the high incidence of heart attacks in men, whose levels of the protective hormone are low throughout their lives.

It may turn out, too, that certain personality types are more susceptible. "It is safe to say," Wittstein says, "that there is a high prevalence of underlying depression and anxiety in those who experience the syndrome. We may learn that it is a combination of things — chronic depression, low estrogen levels, a genetic predisposition — that come together to make this happen."

Even though the prognosis is so hopeful, the experience can be emotionally life-changing. Brunner keeps her stress level down by doing deep-water walking and taking time out to putter around her house. She makes it a point to travel with friends and nurture relationships with family.

Both Brunner and Newman say they are more conscious of their lifestyle.

"I can't change the kind of person I am," Newman says. "I still take things too seriously. I push myself too hard. But I'm careful not to put myself in situations that I know are going to be too intense. I work at being my own life coach."

As Wittstein says, "Nobody who has gone through this wants to have it happen again."

Contact Gloria Hochman at