The causes of "broken heart syndrome" remain a mystery, but doctors will soon have an easier time recognizing and treating this rare, life-threatening condition, thanks to data being reported at the 30th Annual Scientific Sessions of the Society for Cardiovascular Angiography and Interventions, in Orlando, FL.

Researchers from Brown University in Providence, RI, have developed the largest registry of patients in the United States with Takotsubo cardiomyopathy, informally known as broken heart syndrome because it is often preceded by an emotional or physical shock of some kind and almost always strikes women. One thing is certain: Patients are usually critically ill during the first 48 hours.

"These patients can be difficult to manage for emergency physicians and cardiologists alike," said cardiology fellow Richard Regnante, M.D. "They may be in cardiac arrest, cardiogenic shock, or severe heart failure. They may require advanced life support with airway management and medications to support blood pressure."

In fact, based on symptoms, electrocardiographic (ECG) tracings, and blood tests for heart damage, it often seems as if the patient is having a heart attack. The mystery deepens in the cardiac catheterization laboratory, when the interventional cardiologist finds no blockage in the coronary arteries.

To date, the registry has enrolled 40 patients diagnosed with Takotsubo cardiomyopathy at two major hospitals in Rhode Island over a period of nearly 2½ years. Ninety-five percent were women, and 60 percent experienced some type of stress shortly before coming to the emergency room. The intensity of the stress varied dramatically, however, ranging from armed robbery to a heated argument, tooth extraction, or preparation for a colonoscopy.

"We don't know why some women develop this syndrome after what appears to be minimal stress, while other women experience severely stressful events but don't develop Takotsubo cardiomyopathy," Dr. Regnante said. A surge of stress hormones likely plays a role, he said, but it is also possible that a blood clot temporarily blocks a major artery of the heart, then dissolves before being detected during coronary angiography.

The most common symptom of broken heart syndrome was chest pain, in 70 percent of patients, followed by shortness of breath in 33 percent. All patients had ECG changes suggestive of an acute coronary syndrome, a term that encompasses both heart attack and unstable angina. Troponin-I, a blood test for heart damage, was positive in 95 percent of patients. Twenty percent of patients were unable to breathe on their own and needed a respirator. In all patients, cardiac catheterization showed characteristic abnormalities in the motion of the heart. One patient died of acute heart failure.

The good news is that most patients who survived the first 48 hours had a steady recovery. Thirty one, or 78 percent, of patients had follow-up echocardiography within a few weeks. Heart function was found to be normal in 29 of 30.

Dr. Regnante said that long-term follow-up will be critical to improved understanding of Takotsubo cardiomyopathy. In addition, he and his colleagues are gathering information on patients who have intravascular ultrasound during cardiac catheterization. This imaging test, in which a tiny ultrasound probe is threaded into the coronary arteries on the tip of a catheter, may show whether the patient has clogged arteries or unstable plaques that are not visible on coronary angiography. These findings will help guide long-term treatment.

"Because we don't yet know what causes this phenomenon, we don't know what the best long-term management should include," he said. "As we gather more information on these patients, we can start to understand who is affected by Takotsubo cardiomyopathy, offer more focused long-term care, and make predictions about their outcomes."

Society for Cardiovascular Angiography and Interventions