Researchers have claimed that for some people who survive a heart attack, mental stress, as opposed to physical stress, maybe a stronger predictor of a repeat heart attack or dying from heart disease, a finding that may lead to new interventions to prevent cardiac arrest.
According to the researchers from Emory University in the US, traditional stress tests, have long been used to check blood flow to the heart and gauge the risk of heart problems.
In their current study, presented at the American College of Cardiology's Annual Scientific Session Together with World Congress of Cardiology, they analysed whether the heart condition myocardial ischemia induced by mental stress was associated with poor outcomes among heart attack survivors
It also assessed how this heart condition in which blood flow to the heart is reduced -- such that the cardiac muscle doesn't get enough oxygen -- is linked to mental stress testing, compared to conventional stress brought on by exercise.
In the study, scientists assessed more than 300 young and middle-aged individuals.
They said those who endured myocardial ischemia with mental stress had a two-fold higher likelihood of having another heart attack or dying from heart disease compared with those who did not have cardiac ischemia-induced by mental stress.
"In our study, myocardial ischemia provoked by mental stress was a better risk indicator than what we were able to see with conventional stress testing," said Viola Vaccarino, study co-author from Emory University.
Vaccarino said this was the only study of its kind in this relatively young adult population of heart attack survivors.
"These data point to the important effect that psychological stress can have on the heart and on the prognosis of patients with heart disease. It gives us tangible proof of how psychological stress, which is not specifically addressed in current clinical guidelines, can actually affect outcomes," she said.
According to the researchers, taking into account patients' psychological stress may help clinicians better evaluate the risk of recurrent heart attacks or death seen in some patients surviving a heart attack.
The results, according to the scientists, also underscore the need for strategies to identify the best stress management interventions for these patients.
They studied 306 adults aged 61 years or younger, who had been in the hospital for a heart attack in the previous eight months.
Participants represented a diverse group of patients, the scientists said, with half of them being women, and 65 per cent were African American.
All participants underwent two types of "stress" testing to examine blood flow to the heart -- mental stress testing, and conventional stress testing, the study noted.
The researchers said the patients were followed for a median of three years for the primary endpoint, which included a combination of either the occurrence of a repeat heart attack or cardiovascular death.
Overall, they said mental stress induced myocardial ischemia occurred in 16 per cent of patients, and conventional ischemia in 35 per cent, suggesting that traditional ischemia due to exercise or drug-induced stress is more common.
Over a three-year follow-up, the study said, 10 per cent of the patients (28 individuals) had another heart attack, and two died of heart-related problems.
Heart attack or cardiovascular-related death was more than doubled in patients with mental stress induced ischemia compared with those without mental stress ischemia, the scientists observed.
This relationship between acute mental stress and heart attack or death remained even after adjusting for clinical risk factors and symptoms of depression, according to the study.
In contrast, the researchers said, conventional stress ischemia was not significantly related to the primary endpoint.
"Patients who developed ischemia with mental stress had more than two times the risk of having a repeat heart attack or dying from heart disease compared with those who did not develop ischemia during mental stress," Vaccarino said.
"What this means is that the propensity to have a reduction in blood flow to the heart during acute psychological stress poses substantial future risk to these patients," she added.