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Depression Predicts Heart Rhythm Abnormalities in Heart Attack Patients

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Duke Health News 919-660-1306

DURHAM, N.C. – Duke University Medical Center investigators have found a
strong association between depression and the incidence of irregular and
rapid beating of the heart's main pumping chambers in patients who have been
hospitalized for a heart attack.

This finding is important, the researchers said, because this heart beat
irregularity, known as ventricular tachycardia, can be a precursor of sudden
cardiac death . Interestingly, the researchers found this association
between depression and ventricular tachycardia in patients who were
relatively healthy and that the risk of ventricular tachycardia increased
with increased levels of depression. The researchers also found a link
between anxiety and ventricular tachycardia.

Based on the results of their study, the researchers believe that
hospitalized heart attack patients should be evaluated for depression, and
those who are found to be clinically depressed should have their heart
activity closely monitored.

Ventricular tachycardia, which can be treated with such drugs as beta
blockers, occurs whenever ventricles beat more than 100 times in a minute.
In some cases, the tachycardia may only last for a few beats; however
sustained periods of tachycardia can cause ventricular damage needing
immediate attention.

Duke research assistant Patrick Smith presented the results of the Duke
analysis March 5, 2005, at the annual meeting of the American Psychosomatic
Society in Vancouver. The research was supported by the National Heart,
Lung, and Blood Institute.

"The results of our analysis showed that depression in patients who have
been hospitalized for a heart attack can be a significant predictor of
ventricular tachycardia," Smith said. "Also, the finding that scores from
commonly used tests of depression and anxiety were associated with the
frequency of ventricular tachycardia suggests that depression, anxiety and
these potentially life-threatening dysrhythmias are connected."

For the study, the team followed 72 patients admitted to Duke University
Hospital with a heart attack. Patients were interviewed by a mental health
provider and given standardized tests for depression and anxiety within
three days of admission. All patients were then connected to a heart monitor
that recorded detailed heart beat information continuously over a 24-hour
period.

"We found that almost one in five (18 percent) patients met the criteria
for clinical depression," Smith said. "Of those patients deemed to be
clinically depressed, 38 percent had at least one episode of ventricular
tachycardia, compared to only 10 percent for the non-depressed patients. We
also found a strong correlation between the severity of the depression and
the number of beats of ventricular tachycardia."

Specifically, the researchers found that based on scores from the
commonly used Beck Depression Inventory (BDI), going from a non-depressed
state to mild depression conferred an 81 percent higher risk of suffering
from ventricular tachycardia.

"We were surprised that we saw such a strong association between
depression and ventricular tachycardia in these patients, who were among the
'healthiest' of heart attack patients," said senior researcher Lana Watkins,
Ph.D. "We excluded patients whose left ventricle – the main pumping chamber
-- was pumping at less than 30 percent of its capacity.

"Given that we saw such a strong association in a relatively healthy
population of heart attack patients suggest that depression can be a useful
clinical predictor of ventricular tachycardia," she said.

While the researchers cannot determine whether there is a
cause-and-effect relationship between depression and ventricular
tachycardia, it is known that depression has been linked to activation of
the immune system, as well as alteration of the aggregation properties of
blood platelets. Depression has also been linked to other such
cardiovascular risk factors as insulin resistance, hypertension, obesity,
increased cigarette smoking, alcohol abuse and physical inactivity.

The current study is an analysis of a subgroup of patients enrolled in an
ongoing investigation led by Watkins that could provide insights into the
effects of depression and stress on heart rate variability. Patients whose
hearts are unable to appropriately regulate their beating action in response
to outside stimuli – such as stress and anxiety – are known to be at higher
risk of suffering a heart attack, the researchers said. The researchers hope
correlate the clinical data obtained from portable heart monitors worn 24
hours a day with everyday stressors as recorded in a diary.

"I think primary care physicians, as well as cardiologists, are beginning
to appreciate the role of psychosocial factors in the coronary artery
disease," said Watkins. "What is needed is more of an understanding of the
pathophysiology of this association between depression and coronary artery
disease. With that information, we can then determine whether or not
treating the depression in this group of patients can actually improve
mortality."

She said that depressed heart attack patients should have their heart
rhythm monitored closely, since medical approaches to treating depression
can often take weeks to be effective.

Other Duke colleagues on the study included James Blumenthal, Ph.D.,
Michael Babyak, Ph.D., Anastasia Georgiades, Ph.D., Andrew Sherwood, Ph.D.,
Amy Keeler, and Michael Sketch, M.D., and Ranga Krishnan, M.D.

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