November 20, 2002
IL (AHA) – The rate of
life-threatening heart rhythms more than doubled among New York
heart patients the month after the September 11, 2001 terrorist
attacks, researchers reported at the American Heart
Association's Scientific Sessions 2002.
evaluated patients with an implantable cardioverter-defibrillator
(ICD). An ICD is an electrical generator the size of a pocket
watch that is inserted into the heart to monitor heart rhythm.
It detects life-threatening abnormal rhythms, called
arrhythmias, and delivers an electrical shock to restore normal
Beginning a few
days after the terrorist attack on the World Trade Center, the
rate of ICD discharges increased and remained elevated
throughout the next month.
evaluated 200 patients (average age 69) with ICDs at six clinics
within 100 miles of the World Trade Center. The devices had been
implanted an average of 2.5 years before the terrorist attack.
ICDs can store
monitoring data, allowing comparison of rhythm patterns and
shock rates from different times. The researchers compared ICD
discharge rates for the 30 days before and after the terrorist
attack. In the month before the attack, 3.5 percent (seven
patients) had heart rhythm disturbances that required electrical
shocks from their ICDs. In the 30 days after the attack, 8
percent (16 patients) did – a 2.3-fold increase.
provide compelling evidence of the impact of stress on the
heart, says Marcin Kowalski, M.D., a resident at St.
Luke's-Roosevelt Hospital Center in New York. Even more
important, the findings demonstrate the life-saving value of
ICDs, he says.
all had potentially lethal arrhythmias in the 30 days after the
attack, and they were all successfully treated by ICDs,"
Kowalski says. "This is just another example showing that
patients really benefit from ICDs and that ICDs can help save
have evaluated how stressful events such as earthquakes and
missile attacks have affected the heart in terms of heart attack
and sudden death.
studies showed a spike in the occurrence of heart attack or
sudden death for a short period after the incidents," says
Jonathan S. Steinberg, M.D., chief of cardiology at St.
Luke's-Roosevelt. "The increase in cardiac events tends to be
short-lived and very closely coupled to the inciting event, such
as an earthquake."
However, the New
York spike in ICD activity was not short-lived, perhaps
documenting the persistence of increased psychological stress
after the World Trade Center disaster.
The increases in
ICD discharge did not occur until three days after the terrorist
attack and continued to occur at a cumulative rate throughout
the remainder of the 30-day study period. The discharge rate
returned to pre-attack levels and remained at 2 percent to 3
percent per month during several months of monitoring.
Why the pattern
of cardiac events in the arrhythmia study differed from the
patterns seen in other studies is unclear.
"We don't know
why arrhythmias occur at a particular time or have a full
understanding of why stress causes arrhythmias," Steinberg says.
several physiologic changes that could predispose a person to a
heart attack, heart rhythm disturbance, or other cardiac events,
he says. Chief among the changes are increased clot formation
and nervous-system stimulation.
"If these changes
occur on a regular basis or if they are persistently present,
they could promote arrhythmias or heart attacks; and heart
attacks can cause arrhythmias,” Steinberg says.
looked at various medical and demographic factors that might
have contributed to the increase in arrhythmias. The only
predictor of an arrhythmia after the terrorist attack was the
patients' history of life-threatening heart rhythm disturbances.
surprising to find that people who have had arrhythmias are more
likely to have arrhythmias again," Steinberg says.
A future study
will evaluate whether proximity to the attack site –
specifically, living closer to Ground Zero – influenced a
patient’s likelihood of having an arrhythmia after the terrorist
attack. Several medical centers around the country will
patients need to be aware that real-life, stressful events can
trigger arrhythmias," Steinberg says. "Physicians should
encourage patients with ICDs to practice stress-reduction and
stress-avoidance techniques. It's also important to protect
patients against the effects of increased nervous-system
stimulation by giving them beta-blockers."
Aysha Arshad, M.B.B.S.; Atul Kukar, D.O.; Valentin Suma, M.D.;
Margot E. Vloka, M.D.; Frederick A. Ehlert, M.D.; Bengt Herweg,
M.D.; Jacqueline E. Donnelly; Julie Philip; George Reed, Ph.D.;
and Alan Rozanski, M.D.