Depression a predictor of death after heart attack

Depression a predictor of death after heart attack
SOURCE: Psychosomatic Medicine, September 2008.

Published October 14, 2008

NEW YORK (Reuters Health) - In people who have suffered a heart attack, depression and a high heart rate at night, while often coexistent, are independent predictors of death, according to research published in the journal Psychosomatic Medicine.
Dr. Robert M. Carney of Washington University School of Medicine, St. Louis, Missouri, and colleagues conducted a series of tests in 333 depressed patients and 383 non-depressed patients who'd recently suffered a heart attack and were followed for up to 30 months.
After accounting for a number of potential factors that might influence the results, depressed patients had higher nighttime heart rate (70.7 versus 67.7 beats per minute) and daytime heart rate (76.4 versus 74.2 beats per minute) than non-depressed patients.
Overall, 33 depressed patients (9.9 percent) and 14 non-depressed patients (3.7 percent) died during follow-up. Twenty-four of the deaths among the depressed patients (73 percent) and 10 of the deaths among the non-depressed patients (71 percent) were classified as likely due to cardiovascular causes.
Carney and colleagues also report that "nondepressed patients with low heart rate had the best survival, and depressed patients with high heart rate had the worst."
After adjusting for other major predictors and for each other, depression and a high nighttime, but not daytime, heart rate independently increased the risk of death in these post-heart attack patients.
According to the investigators, disturbed sleep, which is frequently reported in patients with depression, may help explain the association of nighttime elevated heart rate with mortality.
There is evidence that arousals from sleep that are associated with increased heart rate may provoke events related to ischemia (restriction of the blood supply and thus oxygen to the tissues) and abnormal heart rhythms in patients with heart disease, they note.