Findings that may help explain links between the stress of traumatic events and increased risk of cardiac death

Sep 14 2004

Reporting findings that may help explain links between the stress of traumatic events and increased risk of cardiac death, researchers said the rate of potentially life-threatening heart arrhythmias doubled during the month after the World Trade Center terrorist attack in 2001 in patients with implantable cardioverter-defibrillators, not only in the New York area, but also in Florida, according to two new studies in the Sept. 15, 2004 issue of the Journal of the American College of Cardiology.

“It certainly supports the notion that mental stress, regardless of its cause, can have severe cardiac effects, including life-threatening ventricular arrhythmias. It certainly suggests that patients who may be vulnerable to these arrhythmias should be counseled about the risks of stress and to consult a physician should they be exposed to stress,” said Jonathan S. Steinberg, M.D., F.A.C.C., St. Luke’s-Roosevelt Hospital Center and Columbia University College of Physicians and Surgeons in New York.

In the days after the World Trade Center was destroyed, Dr. Steinberg and colleagues who work with heart patients in New York and New Jersey realized that the automatic recorders within implantable cardioverter-defibrillators (ICDs) offered a treasure trove of data on heart rhythms before and after the attack. The devices are designed to deliver corrective shocks to the heart when they detect potentially dangerous arrhythmias. They store data on each event, which is later downloaded during regular checkups.

In the 30 days post-9/11, 16 patients (8 percent of 200 consecutive patients) demonstrated tachyarrhythmias, compared with only seven (3.5 percent) in the preceding 30 days, representing a 2.3-fold increase in risk (95 percent confidence interval 1.1 to 4.9; p = 0.03).

These are the first results documenting such a direct link between a traumatic event and an increase in heart arrhythmias. Although all the patients survived, the researchers say these findings suggest that arrhythmias may play a role in the underlying cause of increased cardiac death rates observed after natural disasters.

However, in contrast to the reports of cardiac deaths spiking immediately after natural disasters and then quickly subsiding, the first arrhythmic event in this group did not occur for three days following 9/11 and the data showed a longer swell in arrhythmias lasting about a month. Also, the events were not concentrated in Manhattan.

“So it was our hypothesis that it wasn’t the shock of the attack itself, but it was the continued threat or some kind of long-lasting effect that may not be specific to a particular locale. We surmised it was mostly due to media exposure or concern about another attack or something along those lines,” Dr. Steinberg said.

Suspecting that the stress may have been felt by heart patients around the country, Dr. Steinberg contacted Anne B. Curtis, M.D., F.A.C.C., Omer L. Shedd, M.D. and their colleagues at the University of Florida and the Veterans Affairs Medical Center in Gainesville, Fla. to see what their ICD patients were experiencing.

“They in essence duplicated our study in their work and came to, surprisingly, almost identical findings,” Dr. Steinberg said.

Dr. Shedd also did not expect to see these results in patients almost a thousand miles from the attack.

“I was surprised. I actually did not feel that we would see an effect when we first began to think about the study. At the time, I knew of the results of the original New York study, but I thought patients were not likely to experience these same problems if they were not physically near the attacks. I think this says a lot about the power of our media. When events such as 9/11 are brought into our homes by television, the Internet or newspapers people are clearly moved by what they are seeing, and they physically share in the experience just as if they were near the event,” Dr. Shedd said.

Among 132 consecutive Florida patients with ICDs, 14 patients (11 percent) had ventricular tachyarrhythmias in the 30 days following the World Trade Center attack, compared with five (3.8 percent) in the preceding 30 days (p = 0.0389, 95 percent confidence interval [CI] 0.4 to 13.3). Although this represents a 2.8-fold risk increase, Dr. Shedd said he would not conclude the effect was larger in Florida than in New York.

“The medical community should take seriously the effects of stress. When there are events that have widespread effects and exposure, including terrorist attacks, but also other natural and unnatural events, we ought to be prepared to deal with the consequences of stress, including the increased risk of life threatening arrhythmias,” Dr. Steinberg said.

Dr. Shedd agreed that clinicians should watch out for effects of stressful events on heart patients, even when the events occur far away, and possibly consider prescribing anti-anxiety medications.

“The other obvious implication is that we likely grossly underestimated the clinical impact of the 9/11 attacks on thousands of patients across the country, and we as providers should do a better job of providing support for such patients should future events occur,” Dr. Shedd said.

The researchers said that although everyone is affected by traumatic events, healthy people should not be overly concerned about their heart rhythms.

“The likelihood of experiencing a life threatening arrhythmic event is really limited to those patients who already have significant heart disease, usually people who have had sizeable heart attacks in the past. So the great majority of citizens are not at risk of truly dangerous events. They may feel the effects of stress and some may be physiologic. You can have an increased heart rate, you may see some extra beats, that kind of thing, but the likelihood of anything truly dangerous happening is very small, unless you have heart disease,” Dr. Steinberg said.

The researchers noted that both groups of patients were small. The researchers did not have information on whether there was any previous history of anxiety.

Rachel Lampert, M.D., F.A.C.C. at the Yale University School of Medicine, who was not connected to this research, said it is exciting to see evidence of both the role of arrhythmias in stress-related cardiac events as well as the potential influence of the media.

“This is really the first paper that has shown that arrhythmias themselves increase during times of population stress, which tells us that it may be one mechanism of the previously well-described phenomenon of sudden death during population disasters,” Dr. Lampert said. “This study shows the power of the media to take population catastrophes home to all of us, not just emotionally, but physiologically as well. It’s the first time this has been shown in this way.”

Kathryn A. Glatter, M.D., F.A.C.C. at the University of California in Davis, who also was not part of this research effort, remarked on the evidence of a long-distance effect from a traumatic event.

“Patients living in Florida who had defibrillators received more shocks immediately after the attacks than before it.” Dr. Glatter said.