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Volume 3 Issue 199 Published - 14:00 UTC 08:00 EST 22-Oct-2001 Next Update - 14:00 UTC 08:00 EST 23-Oct-2001
| Editor: Susan K. Boyer, RN © RAmEx Ars Medica, Inc. All rights reserved. |
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 Abnormal Heart Responses May Tie Depression To Heart Attack Deaths
Depression in heart attack patients may affect much more than their mental health. It may also affect the wiring of their heart, increasing the likelihood of death, according to research published in today's Circulation: Journal of the American Heart Association. This study followed a subset of participants in the Enhancing Recovery in Coronary Heart Disease (ENRICHD) clinical trial admitted to coronary care units between 1997 and 2000. Three hundred and seven individuals had been diagnosed with major or minor depression as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and 366 had not. All had suffered heart attacks in the 28 days before joining the trial. They each underwent 24-hour ambulatory electrocardiographic (ECG) monitoring after hospital discharge to measure changes in heart rate rhythm. The ECG tapes were used to assess their heart rate variability (HRV). HRV measures cardiac autonomic function, which includes the sympathetic and parasympathetic nervous systems. These help control blood vessel size, blood pressure, the heart's electrical activity and its ability to contract. Low HRV reflects excessive sympathetic or reduced parasympathetic function and is a strong independent predictor of post-heart attack death. "Earlier studies have found that depressed patients have higher sympathetic nervous system activity and higher levels of stress hormones than non-depressed patients," says primary researcher Robert M. Carney, Ph.D., professor of medical psychology at Washington University School of Medicine, St. Louis. "Our results support the possibility that altered cardiac autonomic nervous system activity could explain the effects of depression on mortality in patients with heart disease." A previous study established that a score of very low frequency power below 180 milliseconds squared (ms2) confers an increased risk of death in the first two and a half years after a heart attack. A very low frequency power score indicates low HRV. Depressed patients were twice as likely (16 percent vs. 7 percent for non-depressed patients) to have scores below that level. Researchers say it is possible that any form of depression after a heart attack lowers HRV and increases the risk of death. However, additional research is needed. The work was supported in part by the National Institutes of Health. Co-authors were: James A. Blumenthal, Ph.D.; Phyllis K. Stein, Ph.D.; Lana Watkins, Ph.D.; Diane Catellier, Ph.D.; Lisa F. Berkman, Ph.D.; Susan M. Czajkowski, Ph.D.; Christopher O'Connor, M.D.; Peter H. Stone, M.D.; and Kenneth E. Freedland, Ph.D. |
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