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Study Finds Lingering Heart Problems After 9/11

Dangerous heart rhythms persisted a month after attacks

WEDNESDAY, Nov. 20, 2002 (HealthDayNews) -- Doctors have long known that extreme stress can contribute to heart attacks, but new research shows the increased incidence of dangerous heart arrhythmias can persist up to a month later.

Beginning a few days after the Sept. 11, 2001, terrorist attacks, researchers evaluated 200 heart patients who lived within 100 miles of the World Trade Center. All of the men and women in the study had an implantable cardioverter defibrillator (ICD), an electrical generator the size of a pocket watch that's inserted into the heart to monitor rhythm.

When the ICD detects a heart arrhythmia, it delivers an electrical shock to restore normal rhythm. While not all arrhythmias are dangerous, some can be precursors to a heart attack or stroke.

The device keeps a record of the number of times it delivers a shock.

Researchers compared the number of times the ICD shocked the heart in the 30 days leading up to the attacks and the 30 days afterwards. They found the device activated 2.3 times more often after the attacks than before. In the month before the strikes, 3.5 percent (seven patients) had heart rhythm disturbances that caused the ICD to shock the heart; in the 30 days after, 8 percent (16 patients) did.

"What this gives us is hard evidence that life-threatening arrhythmias can result from exposure to stressful events," says Dr. Jonathan S. Steinberg, lead author of the study and chief of cardiology at St. Luke's-Roosevelt Hospital Center in New York City. "We were surprised at how sustained it was."

The study was presented today at the American Heart Association's scientific sessions meeting in Chicago.

Doctors have long suspected that intense stress can bring on heart attacks. Previous research has shown a spike in heart attacks after earthquakes or missile attacks.

However, that research has shown the spike "tends to be short-lived and very closely coupled to the inciting event," Steinberg says.

In his study, the uptick in ICD activity lasted an entire month, Steinberg says. "We presume the anxiety and intense media exposure afterwards prolonged the stress," he says.

The increase in ICD discharge, which began a few days after the attacks, returned to pre-attack levels after a month.

Doctors are still trying to figure out the precise relationship between stress and heart problems. One possibility is that stress causes an activation of the nervous system, which stimulates the heart. This could bring on an arrhythmia in susceptible people, Steinberg says.

Stress can also cause a narrowing of the blood vessels and therefore increases blood clotting, which can be a cause of a heart attack, he adds.

"The message for people with serious heart conditions is that events can have consequences on one's health," he says. "If you have a heart condition, you should take steps to shield yourself from intense stressful events."

Dr. Freddy Abi Samra, medical director of the electrophysiology laboratories at the Ochsner Clinic Foundation in New Orleans, says the study provides added evidence that emotional and mental stress can contribute to cardiac events.

"Previous research has shown cyclical variations in heart attacks," Abi Samra says. For example, there's a spike in heart attacks on Monday mornings.

However, he notes, not all arrhythmias are lethal, or even dangerous.

ICDs are programmed to shock the heart within a few seconds of detecting an arrhythmia. While certain types of arrhythmias can be precursors to cardiac arrest, others aren't dangerous and will simply subside on their own.

"The ICD doesn't wait to find out," he says. "That means every shock isn't preventing a lethal event. Sometimes it's not even appropriate."

Stressful times can also increase the incidence of these non-lethal rapid or irregular heartbeats. "They might be measuring some of those, too," Abi Samra says.

What To Do

For more information on arrhythmias, visit the National Heart, Lung, and Blood Institute or the American Heart Association.

SOURCES: Jonathan S. Steinberg, M.D., chief, cardiology, St. Luke's-Roosevelt Hospital Center, New York City; Freddy Abi Samra, M.D., medical director, electrophysiology laboratories, Ochsner Clinic Foundation, New Orleans; Nov. 20, 2002, presentation, American Heart Association scientific sessions meeting, Chicago
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