November 20, 2013
Stress Particularly Dangerous For Young Women Who’ve Had Heart Attacks
Brett Smith for redOrbit.com - Your Universe Online
Younger women who are hospitalized after a heart attack have a much higher rate of complications and mortality than men of the same age.A new study from Emory University may shed some light on that discrepancy as researchers have found that women under 50 with a recent heart attack are more likely to have restricted blood flow to the heart, also called myocardial ischemia, during times of psychological stress. The study is being presented on Wednesday at the American Heart Association Scientific Sessions in Dallas.
To reach their conclusion, the researchers’ Myocardial Infarction and Mental Stress (MIMS) study included 49 men and 49 women, who all had a heart attack within a six-month span. Participants’ ages ranged from 38 to 59.
"This is the first study to examine the cardiovascular effects of psychological stress as a possible mechanism for the greater mortality after myocardial infarction among younger women," said study leader Dr. Viola Vaccarino, chair of the epidemiology department at Emory. "We saw a dramatic difference in mental stress-induced ischemia specifically in younger women. In addition, when ischemia was graded in a continuous way, we saw that it was twice as severe among the younger women."
Even when investigators considered heart disease risk factors, such as smoking and diabetes, they came to the same conclusion about these young heart attack victims. The researchers speculated that these women were experiencing higher levels of psychosocial stress, as many of them were poor, of minority race, and with a history of abuse and depression.
"Yet if we look at the statistics, factors such as poverty, race and depression do not explain the difference," Vaccarino said. "Yes, women have more stressors. But our data show that women also may be more vulnerable to the effects of mental stress on the heart."
"This could be an added stimulus to the medical community to pay more attention to the emotional factors in cardiac patients,” said added. “We are now taking a closer look at potential physiological factors that account for the additional susceptibility in younger women."
The Emory researchers said they were able to identify two potential causes that are specific to younger women who had a recent heart attack: inflammation and heart rate variability, a statistic used to measure the reaction of the autonomic nervous system.
The study researchers also found that women age 50 and below had much higher blood levels of Interleukin-6 (IL-6), a stress-induced marker of inflammation, compared to similarly aged men, both before the clinical stress test and afterwards. The team found that women and men older than 50 had similar levels of IL-6.
Low heart rate variability has been connected to a higher heart disease risk in previous studies, as higher heart rate variability is associated with a more flexible, and therefore healthier, autonomic nervous system. The study team found that younger female participant’s heart rate variability fell more in response to stress, compared to their male counterparts – further evidence that young women after a heart attack may be more susceptible to the unfavorable effects of psychological stress on the heart.