"This is a sudden weakening of the heart muscle, which is triggered by a sudden, unexpected mental stress ... such as the death of a loved one," Murali said.
Champion, who has seen 200 to 250 cases over his career, believes the syndrome "is much more common than we think".
It can follow a family argument or armed robbery or occur if someone fears public speaking or a medical procedure, Champion said. His most notable case, he added, involves a woman who "went to a surprise birthday and truly was surprised".
Physical events such as a head injury or stroke apparently also can spark heart failure, researchers say.
The condition strikes women much more often than men, especially women beyond menopause.
Stress cardiomyopathy's symptoms mimic those of a heart attack: chest pain, shortness of breath, arm or facial numbness. But, there are a couple of big differences beyond the emotional stress that precedes stress cardiomyopathy.
While heart muscle dies during a heart attack, it usually can completely recover from broken heart syndrome with proper and immediate treatment. Also, stress cardiomyopathy releases much higher levels of stress hormones - including adrenaline, or epinephrine and norepinephrine - in the bloodstream.
Champion authored a study, published in the New England Journal of Medicine in 2005, directly linking the syndrome and the body's response to emotional stress. Nineteen patients who sought treatment for heart attack symptoms after a shock were compared to a smaller group that had heart attacks without preceding emotional events.
The 19 experiencing shocks had "levels of adrenaline far higher than even the worst of heart attacks," Champion said. The study also showed that their left ventricular dysfunction present on hospital admission quickly went away over the next few days.
Three theories have evolved about the sources of stress cardiomyopathy, said Martin Samuels, a neurologist and Harvard Medical School professor who studies the nervous system and heart function. They involve stress hormones toxicity, spasm of the coronary arteries, and myocarditis or heart inflammation.
"They are all connected by the fact that the cascade of events is triggered from the central nervous system," Samuels said. "These events occur when there is a stress or a brain disease like a seizure, head injury or stroke. The brain causes the surge in the stress hormones." The nervous system, Samuels said, is "capable of causing malfunction of the heart and an actual structural change ... and it could cause sudden cardiac death". He doesn't consider spasm a central cause.
Champion said he believes the cause "is more likely a direct toxic effect of adrenaline on the heart muscle".
But "adrenaline alone is not the explanation here," Murali said, "because the level goes up during physical stress, too, and people generally don't develop" stress cardiomyopathy in that situation.
Champion cited physical triggers: "Most common are anything involving the head and neck," including tumours there, insertion of a breathing tube during surgery, blood clots in the lungs, blows to the head or migraine.
The UPMC researcher believes some patients are "genetically predisposed", and then something stressful occurs. He is genotyping patients for a research study.
He and his colleagues also are studying why women, particularly those who are postmenopausal, get stress cardiomyopathy more often than men.
One possible reason is that postmenopausal women are more likely to seek medical attention for heart attack symptoms than younger women are, he said, citing "selection bias".
A second possibility involves "heart chemistry," he said, and how "when you lose the sex hormones oestrogen and progesterone, that it predisposes someone to react differently to those elevated adrenaline levels".
If heart attack symptoms develop after a stressful event, seek medical help right away, Champion and Murali agree.
"One should take immediate action by getting to an emergency room and getting evaluated quickly," Murali said.
That includes taking a complete history, including an account of the stressful event. The doctor should order blood work to check for enzymes released because of a heart attack and a diagnostic test such as ultrasound, electrocardiogram or a heart catheterisation.
"This syndrome is ... a diagnosis of exclusion," Champion said. "You have to diagnose it after you've ruled out other potential problems."
If the patient gets good medical support for the first 24 to 48 hours, he added, "then you have a good chance of (the patient) surviving".
- AAP
