Mental stress-induced ischemia in the laboratory and ambulatory ischemia during daily life. Association and hemodynamic features.
ABSTRACT The purpose of this study was to determine the correspondence of mental stress-induced ischemia in the laboratory with ambulatory ischemia and to assess the relationship between hemodynamic responses to mental stress and the occurrence of ischemia. Although exercise testing is usually used to elicit myocardial ischemia, ischemia during daily life usually occurs at relatively low heart rates and in the absence of strenuous physical exercise. Mental stress has been shown to trigger ischemic events in the laboratory at lower heart rates but at blood pressures comparable to exercise. We therefore compared the extent to which mental stress and exercise testing identify patients who develop ischemia out of hospital.
One hundred thirty-two patients with documented coronary disease and recent evidence of exercise-induced myocardial ischemia underwent 48-hour ambulatory monitoring and radionuclide ventriculography during exercise and mental stress testing. Patients who displayed mental stress-induced ischemia in the laboratory were more likely to exhibit ischemia during daily life (P < .021). Furthermore, patients who exhibited ischemia during ambulatory monitoring displayed larger diastolic blood pressure (P < .006), heart rate (P < .039), and rate-pressure product responses (P < .018) during mental stress.
Among patients with prior positive exercise stress tests, mental stress-induced ischemia, defined by new wall motion abnormalities, predicts daily ischemia independent of exercise-induced ischemia. Exaggerated hemodynamic responses during mental stress testing also identify individuals who are more likely to exhibit myocardial ischemia during daily life and mental stress.
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ABSTRACT: 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.International Journal of Psychophysiology 07/2006; 60(3):274-83. DOI:10.1016/j.ijpsycho.2005.07.005 · 2.65 Impact Factor
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ABSTRACT: Standard noninvasive impedance cardiography has been used to examine the cardiovascular responses of individuals to a wide range of stimuli in critical care and laboratory settings. It has been shown to be a reliable alternative to invasive thermodilution techniques and an acceptable alternative to the use of a pulmonary artery catheter. Ambulatory impedance cardiography provides a similar assessment of cardiac function to standard noninvasive impedance cardiography, but it does so while individuals engage in activities of daily living. It offers portability and the option of managing complex patients in outpatient settings. To critically examine through a literature analysis the validity, reliability, and sensitivity of ambulatory impedance cardiography for the assessment of cardiac performance during activities of daily living. The Cochrane Database of Systematic Reviews (CDSR), The Cochrane Database of Methodology Reviews (CDMR), The Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), National Health Service Economic Evaluation Database (NHS EED), Health Technology Assessment (HTA), and The Cochrane Methodology Register (CMR; 1966-2005); MEDLINE (1950-2005); and CINAHL (1982-2005) were searched using the following terms: ambulatory cardiac performance, impedance cardiac performance, AIM cardiac performance monitor, thoracic electrical bio-impedance, impedance cardiography, ambulatory impedance monitor, bio-impedance technology, ambulatory impedance cardiography, bio-electric impedance; also included were reference lists of retrieved articles. Studies were selected if they used an ambulatory impedance monitor to examine one or more of the following cardiovascular responses: pre-ejection period (PEP), left ventricular ejection time (LVET), stroke volume (SV), or a combination of these. Studies have been predominantly descriptive and have been focused on a young, male population with a normal body mass index (BMI; 25-29 kg/m). Inconsistencies in determining specific markers of cardiac function (e.g., PEP and SV) across studies necessitated that results be reported by outcome for each study separately. Ambulatory impedance monitors are valid and reliable instruments used for the physiologic measurement of cardiac performance. Sensitivity is established utilizing within-individual measurements of relative change. This is especially important in light of an aging population and technical advances in healthcare. Further research is warranted using nursing interventions that focus on an older, female population who have a BMI greater than 30 kg/m. Availability of noninvasive ambulatory measures of cardiac function has the potential to improve care for a variety of patient populations, including those with hypertension, heart failure, pain, anxiety, and depressive symptoms.Nursing Research 01/2006; 55(4):283-91. DOI:10.1097/00006199-200607000-00009 · 1.50 Impact Factor
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ABSTRACT: Stress produces several physiological and behavioral alterations that increase cardiovascular morbidity and mortality. Nonetheless, there is a dearth of studies that have evaluated the effects of stress on total plasma homocysteine, an important amino acid associated with cardiovascular disease. We used four distinct acute stressors in rats, i.e., swimming, restrain, novelty and cold exposure, in order to examine whether any acute effect on total plasma homocysteine concentrations would occur. Plasma corticosterone and adrenocorticotropic hormone concentrations were also measured to demonstrate the ability of the chosen manipulations to activate the hypothalamic-pituitary-adrenal (HPA) axis. Three of the four stressors activated the HPA axis and only restrain affected total plasma homocysteine concentrations (+37%, P=.006) compared with the control group. The complexity of the physiological responses to stress, the peculiarities of stress responses and the intricate regulatory systems involved in homocysteine metabolism must be taken into account in order to clarify the increasing effect of restrain (mainly a psychological stressor) on total plasma homocysteine concentrations in rats and to evaluate its meaning in human pathology.Pharmacology Biochemistry and Behavior 03/2004; 77(2):269-73. DOI:10.1016/j.pbb.2003.11.003 · 2.82 Impact Factor