UF Researchers Link World Trade Center Attack To Rise In Heart Arrhythmias In Florida Patients

March 8, 2004

GAINESVILLE, Fla. — In the month after the Sept. 11, 2001, attack on the World Trade Center, millions grappled with the emotional heartache of a national tragedy. Scientists now have discovered new evidence of physical consequences for the heart as well among patients living hundreds of miles from Ground Zero who rely on a pacemaker-like device that corrects dangerously rapid arrhythmias with electric shock.

University of Florida researchers found that patients who saw a doctor for routine monitoring of the device, known as an implantable cardioverter defibrillator, or ICD, had a nearly three-fold increase in the number of shocks they received in the four weeks after Sept. 11. The scientists will present their findings today (3/8) at the annual scientific meeting of the American College of Cardiology in New Orleans.

An estimated 400,000 people die from unstable heart rhythms each year. Experts say an additional 80,000 receive an ICD, which works by constantly monitoring the heartbeat, halting dangerously rapid rhythms by delivering a small electrical jolt to the heart. It also can correct abnormally slow heart rhythms by pacing the heartbeat with electrical pulses.

UF experts collaborated with researchers at St. Luke’s-Roosevelt Hospital in New York, who previously noted an increase in the incidence of arrhythmias and the frequency of ICD shocks among patients living in the metropolitan area in the month after the attack. The current study was the first to show a similar effect in patients living at a distance. The findings prompt speculation that terrorism, major life stress and mass disasters might trigger adverse effects among heart patients nationwide, even if they live in an area not directly touched by these events.

“This is the first time after a tragedy has occurred in our country that anybody has looked to see whether it affects patients all across the country,” said Dr. Omer Shedd, a postdoctoral fellow in cardiovascular medicine at UF’s College of Medicine. “Because the World Trade Center attacks were so heavily publicized – virtually everybody in the country was exposed to that tragedy – we thought we may find an increase in morbidity and possibly mortality in our area. The implications are that the event had a much more widespread effect than previously recognized.”

Physicians increasingly acknowledge that emotional stress is a powerful stimulus for cardiovascular events. Previous research has directly linked cardiovascular and psychological reactions in people experiencing sudden and severe life stress, such as the aftermath of a natural disaster or the terror of war. The number of heart attacks and sudden deaths, for example, increased among Israelis after the Scud missile attacks on Israel during the Gulf War. Similar effects have been noted among Californians after major earthquakes. The threat of terrorism has raised additional concern, researchers say.

“There are some data to suggest that a lot of arrhythmias are anxiety-driven,” Shedd said. “When people become anxious, the levels of certain hormones in the body increase, and that can trigger rhythm problems and heart problems.”

If doctors could better characterize or identify patients prone to experiencing high levels of anxiety, whether it’s related to a national event or an event at home such as the loss of a family member, then perhaps they could help prevent arrhythmias and other cardiovascular complications, Shedd said.

For the current study, UF scientists reviewed the medical records of 132 Floridians, mostly men, who were seen for routine checkups at UF or at Gainesville’s Malcom Randall Veterans Affairs Medical Center, both in the month before and the month after the Sept. 11 attack. The average age of those enrolled in the study was about 63. The frequency of heart arrhythmias requiring ICD treatment increased by more than 68 percent among the study participants shortly after the attack. Patients with arrhythmias in the month before also experienced twice as many in the month afterward.

In all, 11 percent of study participants had abnormal heart rhythms in the month afterward, compared with 3.5 percent in the month before. Because the research was a retrospective study, however, scientists do not know whether the patients were personally touched by the tragedy, through knowing friends or relatives living in the New York metropolitan area.

“These data provide real-world evidence that stress affects both the mind and the heart,” said UF psychologist Sam Sears Jr., of the College of Public Health and Health Professions “Even witnessing a national tragedy has a similar effect as experiencing a tragedy. It doesn’t have to be a death in your family for it to affect the heart. Fortunately, the ICD protects patients under these unusually stressful circumstances. What’s interesting about this study was that the effect occurred because they were Americans. It suggests we’ve internalized our identity and (the victims’) identity as Americans.”

The key is to get at-risk patients the psychological help they might need to cope with stressful events, and to let them know that if they do experience an increase in arrhythmias caused by stress they are likely to subside with time, said Dr. Anne B. Curtis, a professor of cardiovascular medicine at UF’s College of Medicine.

“When tragedies like this happen we’ve got to anticipate that patients may have more events,” Curtis said. “And if they do, we need to reassure patients that it may simply be related to the stress of the situation, more so than to the notion that the underlying arrhythmia may have changed in a substantial way.”

In coming months, researchers will continue to assess the effects of patient anxiety, depression and other psychological problems on arrhythmias, and on the incidence and frequency of shocks in patients with ICDs.

“One of the things we’d like to do is find better ways to identify those patients before these kinds of events happen,” Shedd said. “We also want to learn the best way to treat patients like this. Do they need long-term medications for anxiety or depression, or are we better off giving them a so-called ‘pill-in-the-pocket,’ which they can use at a time when they are experiencing a lot of anxiety? We don’t know if that would work or not. Those are some areas we’d like to look into.”

Sandra B. Dunbar, a professor of nursing and medicine at Emory University who is testing an education-based stress reduction intervention in ICD patients, called the UF study important, saying, “It emphasizes the importance of the lifesaving technology, as many of these patients would have died without their ICDs. And it clearly supports the need to better prepare cardiac patients for dealing with stress and anxiety to prevent arrhythmias. Future studies that incorporate nondrug approaches, such as teaching coping techniques, would be important.”