Heart Break Syndrome : ExplanationIn Biotechnology
The mysterious malady mimics heart attacks, but appears to have little connection with coronary artery disease. Instead, it is typically triggered by acute emotion or physical trauma that releases a surge of adrenaline that overwhelms the heart. The effect is to freeze much of the left ventricle, the heart’s main pumping chamber, disrupting its ability to contract and effectively pump blood.
The phenomenon is a “concussion” of the heart, says Scott Sharkey, a cardiologist at Minneapolis Heart Institute. “It’s really a heart attack which is triggered by stress rather than by a blocked artery,” he says.
For reasons that aren’t fully understood, the problem, formally known as stress-induced cardiomyopathy, afflicts mostly women after menopause. The syndrome is relatively uncommon, accounting for an estimated 1% to 2% of people—and about 6% of women—who are diagnosed with a heart attack. In addition to such common emotions as grief and anger, doctors say broken-heart syndrome has been triggered by a person’s anxiety over making a speech, a migraine headache or the emotional response to a surprise party. It can be fatal on occasion, but for the most part patients recover quickly, with no lasting damage to their hearts.
In a conventional heart attack, an obstructed artery starves the heart muscle of oxygenated blood, quickly resulting in the death of tissue and potentially permanently compromising heart function. In contrast, the heart muscle in broken-heart-syndrome patients is stunned in the adrenaline surge and appears to go into hibernation. Little tissue is lost. “The cells are alive, but mechanically or electrically disabled,” Dr. Sharkey says.
When patients are hospitalized with broken-heart syndrome, their hearts might be pumping at as little as 20% efficiency, a mark of serious heart failure, says Chet Rihal, a cardiologist and director of the catheterization clinic at Mayo Clinic, Rochester, Minn. But within 48 to 72 hours, many recover to the 60% level that is considered healthy. “It’s remarkable how quickly this will occur and how quickly they will recover,” he says.
The phenomenon was first identified in the early 1990s by Japanese researchers, who named the condition “tako-tsubo” cardiomyopathy, because in X-ray images, the left ventricle affected by broken-heart syndrome takes the shape of a vase-like pot used in Japan to trap octopuses.
“The treatment for these patients is really different” than that prescribed for patients with a conventional heart attack. For one thing, it’s risky to give a clot-buster drug to a patient without an arterial blockage, due to the potential to cause a stroke.
Doctors don’t yet understand the mechanism that causes broken-heart syndrome. Nor are there any established ways to identify people who might be susceptible to the condition or known strategies patients might adopt to reduce their risk.
While doctors use blood-pressure pills such as beta-blockers and ACE-inhibitors to help treat the condition, Dr. Sharkey says that about 20% of patients who suffer an attack of broken-heart syndrome are already on such medications.
“This is so powerful that with currently used doses, we haven’t found a way to block it,” he says. The problem recurs in about 10% of cases.
Triggers for broken-heart syndrome seem as varied as the number of people affected. While death of a spouse or other close family member or friend is a common cause, breakups such as a divorce or separation have also sparked the event, according to a study of 136 patients by Dr. Sharkey and his colleagues published Jan. 26 in the Journal of the American College of Cardiology.
For others, being overwhelmed by new software at work, seeing a poultry barn burn down, or losing money at a casino all have brought the condition on, doctors say.
But physical stress can cause a broken heart as well. “The emotional aspects get all the press,” says Dr. Wittstein of Johns Hopkins. “But nonemotional triggers” are at least as common. A sudden drop in blood pressure, an asthma attack, a surgical procedure, an adverse drug reaction and withdrawal from alcohol are among such causes.
One explanation for broken-heart syndrome may lie in the interaction between adrenaline and heart-muscle cells. Adrenaline causes calcium to rush into heart cells, which is how they contract, Dr. Wittstein explains. Some abnormality in the relationship may result in a calcium overload that stuns the heart.
Researchers are also identifying gene variants that may predispose some people to suffering from the condition, he says. Another question is why some events with strong emotion affect people while others don’t.