Usefulness of ischemic response to mental stress in predicting silent myocardial ischemia during ambulatory monitoring

Consistency of Positron Emission Tomography and Myocardial Contrast Echocardiography in Diagnosing Mental Stress-Induced Myocardial Ischemia: Study Protocol of a Prospective Study-Background, Design and Method

Mental stress-induced myocardial ischemia (MSIMI) has attracted increasing attention in the last 30 y. Positron emission tomography/computed tomography (PET/CT) is among the most accurate methods for evaluating myocardial perfusion. Even so, echocardiography seems to be a more harmless option when the radiation exposure and high expense of PET/CT are considered. To date, no previous studies have compared the consistency between echocardiography and PET/CT in the diagnosis of MSIMI. The primary aim of this research was to compare the consistency of myocardial contrast echocardiography and PET/CT in diagnosing MSIMI in women with angina symptom/ischemia but no obstructive coronary artery disease (INOCA). Fifty adult female patients with INOCA were recruited for a 12-min-long mental stress test. Each patient underwent both echocardiography and PET/CT at baseline and during mental stress testing; the interval between the two examinations was 1-3 d and the sequence was assigned naturally. MSIMI is defined by a summed difference score (SDS) ≥3 on PET-CT during mental stress testing. It is also defined by new abnormal wall motion, ejection fraction reduction ≥5%, and/or development of ischemic ST change on the electrocardiogram during mental stress testing. This study examined the consistency of PET/CT and myocardial contrast echocardiography in diagnosing MSIMI.

Brain Correlates of Mental Stress-Induced Myocardial Ischemia

OBJECTIVE

Coronary artery disease (CAD) is a major cause of morbidity and mortality, and despite important advances in our understanding of this disorder, the underlying mechanisms remain under investigation. Recently, increased attention has been placed on the role of behavioral factors such as emotional stress on CAD risk. Brain areas involved in memory and the stress response, including medial prefrontal cortex, insula, and parietal cortex, also have outputs to the peripheral cardiovascular system. The purpose of this study was to assess the effects of mental stress on brain and cardiac function in patients with CAD.

METHODS

CAD patients (N = 170) underwent cardiac imaging with [Tc-99m] sestamibi single-photon emission tomography at rest and during a public speaking mental stress task. On another day, they underwent imaging of the brain with [O-15] water positron emission tomography (PET) during mental stress (arithmetic and public speaking) and control conditions.

RESULTS

Patients with mental stress-induced myocardial ischemia showed increased activation with stress in anterior cingulate, inferior frontal gyrus, and parietal cortex (p < .005). This was seen with both arithmetic stress and public speaking stress. Arithmetic stress was additionally associated with left insula activation, and public speaking with right pre/postcentral gyrus and middle temporal gyrus activation (p < .005).

CONCLUSIONS

These findings suggest that mental stress-induced myocardial ischemia is associated with activation in brain areas involved in the stress response and autonomic regulation of the cardiovascular system. Altered brain reactivity to stress could possibly represent a mechanism through which stress leads to increased risk of CAD-related morbidity and mortality.

Hostility and sex differences in the magnitude, duration, and determinants of heart rate response to forehead cold pressor: Parasympathetic aspects of risk

Recent models hypothesize that hostility confers increased risk of CHD through weaker parasympathetic dampening of cardiovascular reactivity (CVR). We tested this possibility using the forehead cold pressor task, a common maneuver which elicits the "dive reflex" characterized by a reflexive decrease in HR presumably through cardiac-parasympathetic stimulation. Participants were initially chosen from the outer quartiles of a sample of 670 undergraduates screened using the hostility subscale of the Aggression Questionnaire ([Buss, A.H., Perry, M., 1992. The Aggression Questionnaire. Journal of Personality and Social Psychology, 63, 452-459.]). The final sample of 80 participants was evenly divided between men and women and high and low hostility. Following a 10-min baseline, participants underwent a 3-min forehead cold pressor task. The task evoked a significant HR deceleration that was mediated by PNS activation, as assessed by respiratory sinus arrhythmia (RSA). Replicating prior research, men displayed greater decrease in HR. More important, low hostiles maintained larger HR deceleration over time compared to high hostiles although the autonomic basis for this effect was unclear. The findings broaden understanding of hostility and sex-related cardiovascular functioning and support the task as a method for evoking PNS-cardiac stimulation.

Depression and increased myocardial ischemic activity in patients with ischemic heart disease

BACKGROUND

Depression is relatively common in patients with ischemic heart disease (IHD) and is associated with increased risk of mortality and morbidity. However, the mechanisms by which depression adversely affects clinical outcomes of patients with IHD are unknown. This study examined the relationship between depression and myocardial ischemia during mental stress testing and during daily living in patients with stable IHD.Methods and results The Center for Epidemiological Studies-Depression scale (CES-D) was administered to 135 patients with IHD to evaluate depressive symptoms. Radionuclide ventriculography was used to evaluate the occurrence of left ventricular wall motion abnormality (WMA) during mental stress and exercise testing. Forty-eight-hour ambulatory electrocardiography was used to assess myocardial ischemia during daily living. The mean CES-D score was 8.2 (SD 7.4, range 0-47) with a median of 7. Logistic regression models using restricted cubic splines revealed a curvilinear relation among CES-D scores and the probability of ischemia. For patients with CES-D scores <or=19 (81.5% of study population), a 5-point increment in the CES-D score was associated with roughly a 2-fold increase in the likelihood of ischemia during mental stress. For patients with CES-D scores >19, the relation among scores and ischemia during mental stress tended to be inversely related, but the portion of the sample is very small. Similar patterns of results were noted for CES-D scores and ischemia during daily life.

CONCLUSIONS

Patients with mild to moderate depressive symptoms (CES-D scores <or=19) are more likely to exhibit myocardial ischemia during mental stress testing and during daily living. Myocardial ischemia may be one mechanism by which depression increases the risk of mortality and morbidity in patients with IHD. The observed inverse association between higher level of depressive symptoms and ischemic activity needs to be further assessed in large samples.

Psychosocial influences on the development and course of coronary heart disease: current status and implications for research and practice

Psychosocial characteristics predict the development and course of coronary heart disease (CHD). In this review, the authors discussed human and animal research on psychophysiological mechanisms influencing coronary artery disease and its progression to CHD. They then reviewed literature on personality and characteristics of the social environment as risk factors for CHD. Hostility confers increased risk, and a group of risk factors involving depression and anxiety may be especially important following myocardial infarction. Social isolation, interpersonal conflict, and job stress confer increased risk. Psychosocial interventions may have beneficial effects on CHD morbidity and mortality, although inconsistent results and a variety of methodological limitations preclude firm conclusions. Finally, they discussed implications for clinical care and the agenda for future research.

Impact of socioeconomic status on coronary mortality in people with symptoms, electrocardiographic abnormalities, both or neither: the original Whitehall study 25 year follow up

OBJECTIVES

To determine the impact of socioeconomic status (SES) on coronary heart disease (CHD) mortality in people with and without prevalent CHD at baseline.

DESIGN

Cohort study with 25 year follow up; prevalent CHD was defined by Q, ST or T wave electrocardiographic (ECG) abnormalities or symptoms (defined by the Rose chest pain questionnaire and self reported doctor diagnosis) or both. SES was defined by four civil service employment grades.

SETTING

London.

PARTICIPANTS

17 907 male civil servants aged 40-69 years.

MAIN OUTCOME MEASURES

CHD mortality (n=2695 deaths).

RESULTS

The lowest versus highest employment grade was associated with increased CHD mortality (age adjusted hazard ratio 1.56 (95% CI 1.2, 2.1)), prevalence of symptoms and, among symptomatic participants only, the prevalence of Q, ST or T abnormalities. Thirty one per cent of CHD deaths occurred in participants with prevalent CHD at baseline. Among participants without Q, ST or T abnormality employment grade was associated with CHD mortality; the hazard ratios (lowest v highest grade) adjusted for age, systolic and diastolic blood pressure were 1.72 (95% CI 1.4, 2.1) for asymptomatic and 1.52 (95% CI 1.1, 2.1) for symptomatic participants; among participants with Q, ST or T abnormality the corresponding hazard ratios were 1.46 (95% CI 0.7, 2.9) and 1.14 (95% CI 0.6, 2.0) respectively.

CONCLUSIONS

SES was inversely associated with CHD mortality in civil servants with and without prevalent CHD at baseline. Further distinguishing the relative contribution of SES to the initiation and progression of CHD requires repeated measures studies of pre-clinical and clinical measures of CHD.

Prognostic value of mental stress testing in coronary artery disease

This study assesses the prognostic value of mental stress-induced ischemic left ventricular wall motion abnormalities and hemodynamic responses in patients with stable coronary artery disease (CAD). Seventy-nine patients (76 men and 3 women) with prior positive exercise test results were exposed to mental arithmetic and a simulated public speech stress in 2 prior studies. Ischemic wall motion abnormalities were monitored using echocardiography or radionuclide ventriculography (RNV). During mental stress testing, new or worsened ischemic wall motion abnormalities to mental stress and exercise were ascertained, as were peak changes in blood pressure and heart rate to mental stress. The occurrence of subsequent cardiac events (including cardiac death, nonfatal myocardial infarction, or revascularization procedures) was ascertained. New cardiac events were observed in 28 of 79 patients (35%) after a median follow-up duration of 3.5 years (range 2.7 to 7.3). Survival analysis indicated that 20 of 45 patients with mental stress ischemia (44%) experienced new cardiac events more frequently than those without mental stress ischemia (8 of 34; 23%; p = 0.048). Type of cardiac event did not differ between mental stress-positive and stress-negative patients. After controlling for baseline blood pressure and study group status (echocardiography vs RNV), there was a significantly higher relative risk of subsequent events for patients with high versus low peak stress-induced diastolic blood pressure responses (RR = 2.4, confidence interval 1.1 to 5.2; p = 0.03). These results demonstrate that ischemic and hemodynamic measures obtained from mental stress testing may be useful in assessing prognosis in CAD patients with prior positive exercise test results.

Mental stress test is an effective inducer of vasospastic angina pectoris: comparison with cold pressor, hyperventilation and master two-step exercise test

BACKGROUND

Cold pressor, hyperventilation and exercise stress tests were usually used for inducing an angina attack in patients with vasospastic angina pectoris. We induced vasospastic angina attack using the mental calculation stress test, and compared the results with those using other stress tests.

SUBJECTS AND METHODS

Subjects were 29 patients with vasospastic angina pectoris. Their ages were 60.8+/-8.4 years. Coronary vasospasm was induced by an acetylcholine infusion test during coronary angiography. The mental stress test was performed as follows; after memorizing six digits numbers, they repeated these numbers in reverse for 5 min, and performed serial subtraction of 17 from 1000 for 5 min. Blood pressure, heart rate and ECG were recorded every 1-5 min during the mental stress test. The serum concentrations of epinephrine and norepinephrine were measured before and during the mental stress test. We compared these results with those obtained using cold pressor, hyperventilation and the Master two-step exercise stress test.

RESULTS

(1) Eight of the 29 patients (28%) showed ischemic ST-T change, which was caused by the mental stress test. (2) The increase in norepinephrine was greater in patients with an ST-T change than without an ST-T change (0.11+/-0.06 vs. 0.04+/-0.04 ng/ml, P<0.01). (3) The incidence of the ST-T change caused by the mental stress test (28%) was similar to the cold pressor test (27%) and greater than that caused by the hyperventilation test (13%). The incidence of ST-T change caused by the Master two-step test was 55%.

CONCLUSIONS

The mental stress test is an effective inducer of vasospastic angina attack, and attack may be induced by neurohumoral vasoconstrictive reflex and/or increased left ventricular afterload.

Relationship among mental stress-induced ischemia and ischemia during daily life and during exercise: the Psychophysiologic Investigations of Myocardial Ischemia (PIMI) study

OBJECTIVES

The purposes of this database study were to determine: 1) the relationship between mental stress-induced ischemia and ischemia during daily life and during exercise; 2) whether patients who exhibited daily life ischemia experienced greater hemodynamic and catecholamine responses to mental or physical stress than patients who did not exhibit daily life ischemia, and 3) whether patients who experienced daily life ischemia could be identified on the basis of laboratory-induced ischemia using mental or exercise stress testing.

BACKGROUND

The relationships between mental stress-induced ischemia in the laboratory and ischemia during daily life and during exercise are unclear.

METHODS

One hundred ninety-six stable patients with documented coronary disease and a positive exercise test underwent mental stress testing and bicycle exercise testing. Radionuclide ventriculography and electrocardiographic (ECG) monitoring were performed during the mental stress and bicycle tests. Patients underwent 48 h of ambulatory ECG monitoring. Hemodynamic and catecholamine responses were obtained during mental stress and bicycle tests.

RESULTS

Ischemia (reversible left ventricular dysfunction or ST segment depression > or = 1 mm) developed in 106 of 183 patients (58%) during the mental stress test. There were no significant differences in clinical characteristics of patients with, compared with those without, mental stress-induced ischemia. Patients with mental stress ischemia more often had daily life ischemia than patients without mental stress ischemia, but their exercise tests were similar. Patients with daily life ischemia had higher ejection fraction and cardiac output, and lower systemic vascular resistance during mental stress than patients without daily life ischemia. Blood pressure and catecholamine levels at rest and during the mental stress tests were not different in patients with, compared with those without, daily life ischemia. Patients with daily life ischemia had a higher ejection fraction at rest and at peak bicycle exercise compared with patients without daily life ischemia, but there were no other differences in peak hemodynamic or catecholamine responses to exercise. The presence of ST segment depression during routine daily activities was best predicted by ST segment depression during mental or bicycle exercise stress, although ST segment depression was rare during mental stress.

CONCLUSIONS

Patients with daily life ischemia exhibit a heightened generalized response to mental stress. ST segment depression in response to mental or exercise stress is more predictive of ST segment depression during routine daily activities than other laboratory-based ischemic markers. Therapeutic management strategies might therefore focus on patients with these physiologic responses to stress and on whether lessening such responses reduces ischemia.

Impact of psychological factors on the pathogenesis of cardiovascular disease and implications for therapy

Recent studies provide clear and convincing evidence that psychosocial factors contribute significantly to the pathogenesis and expression of coronary artery disease (CAD). This evidence is composed largely of data relating CAD risk to 5 specific psychosocial domains: (1) depression, (2) anxiety, (3) personality factors and character traits, (4) social isolation, and (5) chronic life stress. Pathophysiological mechanisms underlying the relationship between these entities and CAD can be divided into behavioral mechanisms, whereby psychosocial conditions contribute to a higher frequency of adverse health behaviors, such as poor diet and smoking, and direct pathophysiological mechanisms, such as neuroendocrine and platelet activation. An extensive body of evidence from animal models (especially the cynomolgus monkey, Macaca fascicularis) reveals that chronic psychosocial stress can lead, probably via a mechanism involving excessive sympathetic nervous system activation, to exacerbation of coronary artery atherosclerosis as well as to transient endothelial dysfunction and even necrosis. Evidence from monkeys also indicates that psychosocial stress reliably induces ovarian dysfunction, hypercortisolemia, and excessive adrenergic activation in premenopausal females, leading to accelerated atherosclerosis. Also reviewed are data relating CAD to acute stress and individual differences in sympathetic nervous system responsivity. New technologies and research from animal models demonstrate that acute stress triggers myocardial ischemia, promotes arrhythmogenesis, stimulates platelet function, and increases blood viscosity through hemoconcentration. In the presence of underlying atherosclerosis (eg, in CAD patients), acute stress also causes coronary vasoconstriction. Recent data indicate that the foregoing effects result, at least in part, from the endothelial dysfunction and injury induced by acute stress. Hyperresponsivity of the sympathetic nervous system, manifested by exaggerated heart rate and blood pressure responses to psychological stimuli, is an intrinsic characteristic among some individuals. Current data link sympathetic nervous system hyperresponsivity to accelerated development of carotid atherosclerosis in human subjects and to exacerbated coronary and carotid atherosclerosis in monkeys. Thus far, intervention trials designed to reduce psychosocial stress have been limited in size and number. Specific suggestions to improve the assessment of behavioral interventions include more complete delineation of the physiological mechanisms by which such interventions might work; increased use of new, more convenient "alternative" end points for behavioral intervention trials; development of specifically targeted behavioral interventions (based on profiling of patient factors); and evaluation of previously developed models of predicting behavioral change. The importance of maximizing the efficacy of behavioral interventions is underscored by the recognition that psychosocial stresses tend to cluster together. When they do so, the resultant risk for cardiac events is often substantially elevated, equaling that associated with previously established risk factors for CAD, such as hypertension and hypercholesterolemia.