DURHAM, N.C. -- Heart patients who experience wide emotional swings are more at risk for cardiac abnormalities than patients who remain on an even keel, according to new findings from Duke University Medical Center.
The Duke researchers discovered that heart patients who score high for a personality trait called "emotional responsivity" are at up to four times higher risk of suffering from a condition of reduced blood flow to the heart, or myocardial ischemia, than patients with lower scores. Ischemia, which can identify individuals at risk for permanent damage to heart muscle, usually occurs without pain and goes unnoticed by patients.
People with high levels of emotional responsivity routinely experience a wider range of emotions during the course of a typical day. The good news is that doctors have many tools at their disposal - biofeedback, stress management, relaxation techniques - to help patients control emotional swings.
"In past studies we have shown that negative emotions, such as frustration, tension or sadness, can cause ischemia - both in the laboratory and during real life," said lead investigator James Blumenthal. "Now, it appears that this unique personality trait, emotional responsivity, is associated with cardiac abnormalities.
"After controlling for the levels of stress and negative emotions which trigger ischemia, we still found that these patients had significantly higher risk for ischemia over and above the negative emotions."
Blumenthal and his colleagues published the results of their study in the August issue of the Journal of Consulting and Clinical Psychology. The study was supported by numerous grants from the National Heart Lung Blood Institute.
The Duke team already has demonstrated the links between negative emotions and stress with the increased risk of heart abnormalities in people with heart disease. After noticing in one of these earlier studies that patients with high levels of emotional responsivity also had increased blood pressure, the researchers wanted to know if this previously unrecognized psychological trait had any effect on ischemia in heart patients.
A total of 136 patients (37 with high levels of emotional responsivity, 99 with low levels) with documented heart disease underwent two different tests. The results of both showed clear physiological signs of ischemia correlated with high levels of emotional responsivity.
In the first test, patients were injected with a small dose of a radioactive tracer and then a special camera took moving pictures of the heart as the patient underwent a battery of stress-producing tests.
"Cardiologists noticed abnormalities in the motion of the walls of the left ventricle, the main pumping chamber of the heart, in those patients with higher levels of emotional responsivity," Blumenthal said. "These abnormalities indicate weakening of cardiac function and are clear markers that the individual may have future heart problems."
When compared with the patients with lower emotional responsivity, those who scored higher had three times higher incidence of ischemia in these laboratory tests.
Secondly, patients wore portable electrocardiogram (ECG) monitors for two days. During that time, patients engaged in usual everyday activities and recorded their emotions in a diary. These readings were later correlated with the diary entries.
"Those patients with higher emotional responsivity exhibited ST-segment depression on their ECGs, which is an indication of reduced blood flow to the heart," Blumenthal said. "For cardiologists, this is a standard method for diagnosing ischemia out of the hospital."
High emotional responders had 2.5 times greater incidence of ischemia than the low responders, as measured by ECG readings. Those with high degrees of emotional responsivity in both the laboratory tests and the everyday monitoring combined were at four times greater risk of ischemia, Blumenthal said. The results of the study apply to patients with heart disease, Blumenthal is careful to point out, adding it is still too early to tell if high levels of emotional responsivity have negative effects on people without heart disease. However, he said that even in healthy people, high emotional responsivity does cause a physiological reaction - elevated blood pressure.
The Duke team is already enrolling patients in a new clinical trial teaching behavioral modification techniques to their heart patients.
Joining Blumenthal in the Duke study were Robert Carels, Andrew Sherwood, Michael Babyak, Elizabeth Gullette, Dr. R. Edward Colemen, Dr. Robert Waugh and Dr. Wie Jiang.
Journal
Journal of Consulting and Clinical Psychology