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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report evaluates the relationships of hemodynamic reactivity and determinants of myocardial oxygen demand to myocardial ischemia during mental stress in coronary artery disease patients. Thirty-nine patients and 12 controls were studied by radionuclide ventriculography during three mental tasks (arithmetic, Stroop task, and simulated public speaking). Patients were subdivided into three groups based on the severity of ischemic wall motion responses to the mental stressors. Results revealed that systolic blood pressure (SBP) levels during the mental tasks and SBP reactivity (increases) to stress were highest for the severely ischemic group, lowest for controls, with the mild-moderate ischemic and nonischemic patients in between. Severely ischemic patients started out with lower double product (heart rate x SBP) levels, and reached higher levels during the Stroop and speech tasks. There were no reliable group effects for diastolic blood pressure, heart rate, or left ventricular end-diastolic volumes. Among severely ischemic patients, the most potent task in eliciting ischemia (the speech) was associated with higher cardiovascular levels and elicited greater heart rate, double product, and ventricular volume responses. The present data indicate a relationship between cardiovascular levels and reactivity and the magnitude of ischemia induced by mental stress.
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PMID:Cardiovascular reactivity and mental stress-induced myocardial ischemia in patients with coronary artery disease. 201 44

The recent development of the VEST, an ambulatory radionuclide detector, to measure left ventricular ejection fraction may enhance the detection of ischemia during daily activities in patients with coronary artery disease. The normal range and determinants of ejection fraction responses to stimuli other than physical exercise, however, are not adequately characterized. Therefore, ejection fraction responses to various activities were measured in 18 normal subjects utilizing the VEST. Uniform increases (greater than 5%) in ejection fraction were seen during physical exercise, uniform decreases were seen during cold pressor testing and modest changes (including decreases greater than 5%) were seen in ejection fraction during mental stress, micturition and hyperventilation. Different forms of stress produced significantly different changes in ejection fraction, even when values were controlled for changes in heart rate. Ventricular loading conditions in the form of enhanced blood pressure responses during mental stress may have contributed to the relatively smaller changes in ejection fraction compared with those during exercise. Subjects demonstrating a decrease in ejection fraction during mental stress did not differ from other subjects in hemodynamic reactivity during mental testing but did have evidence of increased parasympathetic tone during cold pressor and bicycle exercise testing. The results reveal that normal ejection fraction response differs among varying physiologic stimuli. These changes are in part related to changes in heart rate and blood pressure; however, other factors, such as neurohumoral regulation, may also play a role. These findings indicate that the patient's activity and the setting in which it occurs must be considered when interpreting ambulatory ejection fraction responses.
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PMID:Comparison of physiologic ejection fraction responses to activities of daily living: implications for clinical testing. 221 67

Acute mental stress may be a frequent trigger of transient myocardial ischemia, myocardial infarction and sudden cardiac death. In an experimental setting, the effect of mental stress on hemodynamics and left ventricular wall motion abnormalities (as detected by radionuclide ventriculography) was measured in 29 patients with exercise-induced myocardial ischemia. Seventy-five percent of the patients demonstrated mental stress-induced wall motion abnormalities. Patients frequently exhibited greater increases in peak systolic arterial pressure during mental stress than during exercise. Personally relevant mental stress is the most potent type of mental stress, both in terms of frequency and magnitude of ischemia. Most mental stress-induced ischemic episodes are clinically and electrocardiographically silent and occur at heart rates significantly lower than those seen during exercise. Both systolic and diastolic blood pressure increased during mental stress-induced ischemia, suggesting that increased myocardial oxygen demand plays a role in the pathophysiology of mental stress-induced transient ischemia. The significant magnitude and acute onset of this mental stress-induced blood pressure elevation may in some manner contribute to atherosclerotic plaque rupture. These findings may provide a pathophysiologic link to the epidemiologic association between mental stress and acute ischemic coronary events. A new ambulatory radionuclide detector that can concurrently monitor left ventricular ejection fraction and electrocardiographic ST-segment change may enhance the detection and evaluation of transient myocardial ischemia in ambulatory coronary patients.
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PMID:Mental stress as an acute trigger of ischemic left ventricular dysfunction and blood pressure elevation in coronary artery disease. 223 10

The current study was designed to examine cardiovascular reactivity to psychological tasks and its relationship to provocation of ischemia in asymptomatic coronary artery disease (CAD) patients with documented silent ischemia and those with painful ischemia. ECG, heart rate, and blood pressure responses to mental stress were collected for 13 patients with coronary artery disease (CAD) and for 6 healthy control subjects. Six of the CAD patients were asymptomatic (documented silent ischemia and no history of angina), while the remaining 7 were symptomatic (history of angina). Three types of mental stress were employed: white noise (a passive stressor), digits repeated backwards (an active stressor), and a math task plus white noise (active + passive stressor). Results indicate that significant increases in heart rate and blood pressure, but not silent ischemic episodes, were induced by the mental stress tasks. In addition, patients with documented exercise-induced and ambulant silent ischemia showed trends of blunted autonomic responsiveness to the stressors. On the digits backwards task, the CAD patients with silent ischemia showed significantly lower diastolic blood pressure responses compared with controls or angina patients. Findings suggest that ischemic episodes are not easily induced by brief mental stress. However, results indicate that asymptomatic CAD patients with silent ischemia may be lacking in autonomic responsiveness, particularly in terms of peripheral resistance, to mental stress in comparison with health controls and symptomatic ischemic patients. Further investigation is needed to explore how patients with silent ischemia typically respond autonomically to mental stress and how blunted reactivity may relate to the provocation of unrecognized ischemic episodes.
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PMID:Cardiovascular reactivity and silent ischemia in response to mental stress in symptomatic and asymptomatic coronary artery disease patients: results of a pilot study. 258 55

We studied the temporal effects of various types of mental stress and physical exercise on the left ventricular ejection fraction (LVEF) in seven normal volunteers and nine patients with coronary artery disease. Three types of psychological stress were administered: mental arithmetic, the Stroop color word test, and a personally relevant speaking task. In the normal volunteers the LVEF response was either flat or increased (p less than 0.05) compared to the baseline value during the mental tasks and increased by a mean of 10 +/- 5% (p less than 0.05) during exercise. In contrast, in patients with coronary disease in whom LVEF did not increase greater than or equal to 5% during exercise, LVEF decreased significantly during the mental tasks (p less than 0.05 for arithmetic and Stroop tasks). Typically LVEF decreased quickly during mental stress with an immediate rebound after intervention. Decreases in LVEF during mental stress occurred without chest pain and were not associated with ECG changes. In patients with coronary disease in whom LVEF increased normally with exercise (LVEF increase greater than or equal to 5%), no significant changes in LVEF occurred during mental stress. The heart rate x systolic blood pressure double product during mental stress was significantly less than that achieved during exercise (p less than 0.05) in each normal subject and patient. Thus psychological stress can provoke acute decreases in LVEF in patients with coronary disease and exercise-inducible dysfunction. The silent nature of the mental stress-induced abnormalities and their occurrence at a lower physiologic workload compared to abnormalities during exercise parallel characteristics of transient ischemia noted during ambulatory monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Transient left ventricular dysfunction during provocative mental stress in patients with coronary artery disease. 274 76

Psychological stress has been demonstrated to induce myocardial ischemia. To determine whether stressful events before a coronary artery bypass grafting procedure precipitate myocardial ischemia, silent or symptomatic, and whether this can have an effect on the prognosis, 26 patients were evaluated before a bypass operation with continuous Holter monitor recording. Specific events monitored were signing surgical consent, receiving preoperative medications, shaving and preparing, and transfer to the operating room. A positive Holter result was defined as an ST segment depression of 1 mm or more lasting one minute or longer. Six patients (23%) were found to have one or more episodes of substantial ST segment depression, with a total of ten episodes lasting 208 minutes recorded. All episodes were silent and not associated with an increase in mean heart rate. The majority of episodes occurred randomly, although three episodes did occur between 5 and 6 AM at the time of transport to the operating room. This appeared to be related more to the circadian rhythm than to the stress of transport. No perioperative or postoperative myocardial infarctions occurred, and all patients were alive at 30 days. In conclusion, silent myocardial ischemia present in the immediate preoperative period does not appear to be related to specific preoperative events. Frequency of early morning ischemia may warrant changes in the medication schedule to provide additional protection during these hours.
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PMID:Anticipation of bypass surgery: can it induce silent myocardial ischemia? 278 70

Myocardial ischemia is an imbalance between consumption and production of adenosine triphosphate (ATP) that leads to ATP depletion and a cascade of biochemical events. Why some patients have pain during these events while others do not is unclear, but some studies indicate that a combination of pain threshold and magnitude of ischemia may be at work. Ischemia can occur during vigorous or daily activities or at rest and can be influenced by mental stress. It is most common in the morning hours, possibly because heart rate, blood pressure, and contractility rise rapidly in the morning and factors that increase coronary vessel tone and reduce blood flow also increase during these hours. The specific pathophysiology of an ischemic episode depends on whether the patient also has chronic stable coronary disease, variant angina, or unstable angina, not on whether the episode is silent or symptomatic.
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PMID:What causes silent myocardial ischemia? 281 27

Ambulatory radionuclide monitoring of left ventricular function was performed with the nuclear Vest device in 35 patients early after acute myocardial infarction. Patients were evaluated during post-infarction treadmill, other activities that included mental stress and cold pressor challenge, and with stress thallium imaging and cardiac catheterization. Of the 35 patients evaluated, 14 had ischemic responses on treadmill testing and 21 had negative responses. By contrast, 20 had redistribution by thallium imaging suggesting ischemia. Vest studies demonstrated 56 responses suggestive of ischemia in 23 patients. Twenty-two occurred during exercise and 13 with mental stress. Seventy-five percent were silent and only 39% had associated electrocardiographic changes. Vest responses were compared in patients whose thallium scan was indicative of ischemia (thallium-positive) and those without ischemia (thallium-negative). Ejection fraction was higher in the thallium-positive group (0.52 +/- 0.11), as compared with thallium-negative patients (0.44 +/- 0.1). With exercise, ejection fraction decreased for the thallium-positive patients from 0.52 +/- 0.11 to 0.40 +/- 0.09 at peak exercise. For thallium-negative patients, ejection fraction changes were not significant. During mental stress, ejection fraction decreased from 0.51 +/- 0.11 to 0.45 +/- 0.12 for thallium-positive patients while thallium-negative patients were unchanged. Vest-measured decreases in ejection fraction of greater than or equal to 5 units during exercise were highly sensitive (90%), specific (73%) and predictive (82%) of a positive thallium scan. The same response for mental stress was specific (87%) and predictive (85%) of a positive scan result.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Usefulness of ambulatory radionuclide monitoring of left ventricular function early after acute myocardial infarction for predicting residual myocardial ischemia. 284 21

Mental stress testing can induce ischemia in coronary patients, but often may not induce chest pain and/or electrocardiographic changes. Therefore, we tested the utility of echocardiography to increase the sensitivity of the method. For this purpose, 56 patients undertook arithmetic mental stress tests and then were subjected to coronary angiography. During the test we evaluated left ventricular function, electrocardiography results, and emotional involvement measured by STAI (State Trait Anxiety Inventory). Echocardiography was positive in 21 patients, and electrocardiogram only in 2 patients. No patient complained of chest pain. The remaining 35 patients were negative. Comparing echo data with coronary angiography, in all the cases, sensitivity was 73.5%, specificity 93.3%. Analysis of the STAI revealed that the negative test we observed could be due to a low stressor efficacy. In conclusion, echocardiography in mental stress testing permits improved sensitivity, with loss of specificity in comparison with conventional electrocardiographic monitoring.
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PMID:Echocardiographic monitoring of mental stress test in ischemic heart disease. 291 4

Coronary heart disease has many different clinical courses: it can cause rhythm-disturbances, sudden death, pump-failure, no pain at all (silent ischemia) or typical angina. Heart-pain can occur "on demand" after physical or mental stress with a duration of 3 to 5 minutes with typical location and good response to nitrates. It also can cause atypical forms of angina such as angina on rest, mostly due to coronary spasms. Angina can stable over months and years but can suddenly increase in severity and duration. This form is called unstable angina, which has to be recognized as soon as possible since acute myocardial infarctions evolve rather frequently. Infarction is an irreversible myocardial damage but before it develops many measures can be taken to preserve the jeopardized myocardium. The recognition and differentiation of angina pectoris is therefore of utmost importance.
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PMID:[Angina pectoris]. 305 92


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