Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The clinical syndrome of angina pectoris was accurately described over 200 years ago by Sir William Heberden. However, in recent years, we have learned that many episodes of myocardial ischemia occur that are not accompanied by symptoms of angina pectoris. These silent ischemic episodes may be detected either during exercise testing, using electrocardiographic criteria that can be combined with scintigraphic studies evaluating myocardial blood flow (thallium perfusion studies) or left ventricular function (gated blood pool scans). In addition, continuous electrocardiographic (Holter) monitoring can be used for the detection of transient ST-segment changes; these changes on Holter monitoring have been correlated with abnormalities of myocardial perfusion and function, indicating that they represent true ischemic events. Studies have shown that patients with coronary artery disease who have evidence of ongoing ischemia, whether symptomatic or silent, have an increased risk for experiencing subsequent cardiac events than patients without evidence of ischemia. Many studies have demonstrated that ischemia during an exercise study after myocardial infarction identifies patients at high risk for recurrent cardiac events, whether or not the ischemia is associated with angina pectoris. Holter monitoring has allowed for the detection of ischemic events out of hospital in ambulatory patients. Studies in stable angina patients have shown that there are many asymptomatic episodes in this setting, which are often occurring at low heart rates during activities of everyday life, without an apparent significant increase in myocardial oxygen demands, and these episodes may even be precipitated by mental stress.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Association between silent myocardial ischemia and prognosis: insensitivity of angina pectoris as a marker of coronary artery disease activity. 332 68

To assess the causal relation between acute mental stress and myocardial ischemia, we evaluated cardiac function in selected patients during a series of mental tasks (arithmetic, the Stroop color--word task, simulated public speaking, and reading) and compared the responses with those induced by exercise. Thirty-nine patients with coronary artery disease and 12 controls were studied by radionuclide ventriculography. Of the patients with coronary artery disease, 23 (59 percent) had wall-motion abnormalities during periods of mental stress and 14 (36 percent) had a fall in ejection fraction of more than 5 percentage points. Ischemia induced by mental stress was symptomatically "silent" in 19 of the 23 patients with wall-motion abnormalities (83 percent) and occurred at lower heart rates than exercise-induced ischemia (P less than 0.05). In contrast, we observed comparable elevations in arterial pressure during ischemia induced by mental stress and ischemia induced by exercise. A personally relevant, emotionally arousing speaking task induced more frequent and greater regional wall-motion abnormalities than did less specific cognitive tasks causing mental stress (P less than 0.05). The magnitude of cardiac dysfunction induced by the speaking task was similar to that induced by exercise. Personally relevant mental stress may be an important precipitant of myocardial ischemia--often silent--in patients with coronary artery disease. Further examination of the pathophysiologic mechanisms responsible for myocardial ischemia induced by mental stress could have important implications for the treatment of transient myocardial ischemia.
 ...
PMID:Mental stress and the induction of silent myocardial ischemia in patients with coronary artery disease. 335 95

Physical exertion is a well-documented trigger of transient myocardial ischemia in patients with coronary disease. More recently, studies have shown that mental stress may also be a cause of myocardial ischemia. The purpose of this study was to examine the relationship of physical activities and perceived mental states to myocardial ischemia while patients were going about their normal daily activities. Twenty-eight patients with documented coronary artery disease underwent ambulatory monitoring of the electrocardiogram. Physical activity and perceived mental status were recorded by patients in a diary which was then graded according to intensity of the activity. Analyses of the continuous electrocardiographic recordings were done separately from the analysis of the diaries. The time of each episode of ischemia, the duration of each episode in minutes and the number of episodes in each 24-hour period were calculated. A total of 372 episodes of ST-segment depression occurred in 912 hours of monitoring. Ischemic events occurring during usual physical and usual mental activities were most frequent (36%). Twenty-six percent of ischemic episodes occurred during increased physical activity, but usual mental activities. Interestingly, 22% of the ischemic events occurred at high levels of mental stress, but low physical activity. Ten percent of episodes occurred during sleep. Although the majority of events occurred during usual daily activities, when duration of ischemia was normalized for time spent in each category, increasing physical or mental activity was associated with an increasing duration of ischemia per unit (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Frequency of ST-segment depression produced by mental stress in stable angina pectoris from coronary artery disease. 336 82

Measures of the severity of angina pectoris, coronary anatomy, and left ventricular function are widely used to assess prognosis and determine management in patients with ischemic heart disease. However, recent evidence suggests that myocardial ischemia, with or without angina, is also a reliable prognostic sign. Studies using ambulatory ST-segment monitoring of patients with chronic stable angina out of the hospital have shown that the majority of episodes of transient myocardial ischemia are silent and surprisingly prolonged. Most episodes occur without the increase in heart rate noted during physical exertion. Characteristic abnormalities of regional myocardial perfusion have been observed using positron tomography during both painful and painless episodes of ischemia. Among these abnormalities is an absolute reduction in the perfusion to the poststenotic ischemic segment of myocardium. Episodes of ischemia can be induced in the hospital by a number of ordinary daily activities, including mental stress, cold, and cigarette smoking, and they often resemble episodes recorded from patients out of the hospital. These observations suggest that both an increased myocardial demand and a reduction in coronary blood flow may be important in the genesis of ischemia out of the hospital. If prospective studies confirm that myocardial ischemia is damaging, even in the absence of angina, investigation and treatment policies may need to be reevaluated. Results of ongoing clinical studies will show whether control of the total ischemic burden can prevent myocardial damage and improve the prognosis.
 ...
PMID:Character and causes of transient myocardial ischemia during daily life. Implications for treatment of patients with coronary disease. 348 93

Ambulatory outpatient monitoring of patients with angina suggests a different view of myocardial ischemia than is conventionally obtained from in-hospital tests. Multiple episodes of ST segment depression occur, and the majority of these disturbances are not associated with symptoms. Recently, studies of regional myocardial perfusion using the technique of positron emission tomography with rubidium 82 have confirmed the ischemic nature of these silent ST changes. Furthermore, activities of everyday life such as mental stress or cold exposure seem to provoke both symptomatic and asymptomatic ischemia, as judged by ST depression and reduced cation uptake. This report presents an unusual case of silent myocardial ischemia observed during the chewing of food.
 ...
PMID:Silent myocardial ischemia during mastication. 349 14

Episodes of transient myocardial ischemia during daily life were investigated in 30 patients on two separate occasions, by ambulatory Holter ST monitoring. The first occasion was at a time of uncertainty in the patients' lives, when the results of coronary angiography and the need for surgery were to be discussed. The second was at a later date, when there had been time to adjust to the decision-making process. There were 515 episodes of myocardial ischemia of which 174 were associated with pain and 341 were asymptomatic. Silent ischemia was significantly more frequent during the first period of monitoring compared to the second (p less than 0.02). Patients who had more silent ischemia on the first occasion also entered more self reports of "emotional upset" (tension, worry, etc.,) in their diaries compared to the second occasion. The level of urinary cortisol was taken as a measure of uncertainty and worry, and was significantly higher on the first occasion (p less than 0.03). Differences in urinary noradrenaline excretion were taken as a measure of subjective stress. Patients who excreted more noradrenaline on the first compared to the second occasion had significantly more silent ischemia (p less than 0.007) and longer total ischemic time (p less than 0.01). We suggest that psychological stress may exacerbate myocardial ischemia which is frequently painless.
 ...
PMID:Psychological stress and silent myocardial ischemia. 363 Aug 89

The management of asymptomatic patients with coronary artery disease (CAD) is controversial, and the level of "activity" of their CAD during normal daily life remains largely unknown. To examine this question, ambulatory Holter monitoring of ST segments was performed out of the hospital in 7 asymptomatic subjects with CAD during normal daily activities. Their condition was detected because they all had a silent positive exercise test and angiographically proved CAD. During a total of 384 hours of monitoring, 37 asymptomatic episodes of ST depression (1 mm or greater and lasting at least 30 seconds) were recorded in 5 of the patients. Most episodes (68%) were 10 minutes or less in duration but ranged from 1 to 253 minutes, and most (70%) had a maximal ST depression of 1 to 2 mm. A small increase in heart rate, ranging from 1 to 34 beats/min, preceded 65% of the episodes, but 35% were associated with no change or even a decline before the onset of ischemia. Fifty-four percent of the episodes occurred during rest or usual light physical activity, 8% during sleep and only 38% during exercise, including 1 prolonged bout while jogging. During 78% of the episodes, the subjects rated their mental activity as usual and only 14% occurred during mental stress. In addition, a distinct diurnal variation was noted with 57% of the ischemia occurring between 0600 and 1200 hours (p = 0.008). Therefore, most asymptomatic subjects had active transient ischemia during daily life, with many of the characteristics already described in symptomatic subjects with CAD.
 ...
PMID:Active transient myocardial ischemia during daily life in asymptomatic patients with positive exercise tests and coronary artery disease. 370 53

Stress is thought to be a coronary risk factor. The main aim of this study is the quantitative analysis of the psychophysiological and cardiovascular activation induced by mental stress in patients (pts) with recent myocardial infarction (Ml). Twenty one pts with recent Ml, after psychological assessment, underwent two consecutive stressors in random sequence: mental arithmetic and Sacks test, during ECG and right heart hemodynamic monitoring. During both stressors there were significant variations (p less than 0.01) of heart rate (HR), systolic and diastolic (dAP) arterial pressures, rate-pressure product (RPP), right atrial pressure (RAP), pulmonary artery end-diastolic pressure (PAEDP), whereas no significant variations in cardiac output could be measured by thermodilution. Of particular interest was the remarkable increase in PAEDP: from 14 +/- 4 (mean +/- SD) to 21 +/- 6 mmHg during mental arithmetic, and from 15 +/- 6, to 20 +/- 6 mmHg during the Sacks test. Mental arithmetic elicited a greater cardiovascular activation than the Sacks test; the differences between the stressors in HR, dPAP, RAP (p less than 0.05) and RPP (p less than 0.01) were all significant. Mental stress in recent Ml challenges the cardiovascular system in measurable quantity, with remarkable increments of left ventricular filling pressure. Its use is suggested for the functional evaluation of pts with recent Ml, although in such setting mental stress seems to be of little value in revealing ischemia and arrhythmias.
 ...
PMID:[Mental stress in the functional evaluation of recent myocardial infarct: hemodynamic aspects]. 666 10

This study assessed the relation between hemodynamic data during a standardized mental stressor and ambulatory ischemia to determine if laboratory-induced responses could predict the magnitude of daily life ischemia. Forty-two men and 11 women, aged 46 to 79 years (mean 61), with coronary artery disease and exercise-induced ischemia were studied. All patients underwent 24- to 48-hour ambulatory electrocardiographic (ECG) monitoring (mean 43 +/- 0.8 hours) and laboratory-induced mental stress using a public speaking task. Hemodynamic data were obtained at rest and every minute during mental stress. Thirty-three of 53 patients (62%) had at least 1 ischemic episode during ECG monitoring. In patients who had ambulatory ischemia, there was a mean number of 7.9 +/- 1.8 episodes (mean total duration 79.2 +/- 24.1 minutes/48 hours). Significant positive correlations were found for peak heart rate and changes in heart rate during mental stress and ambulatory ischemia (r = 0.353 to 0.462, p < 0.05) in patients who had ambulatory ischemia. There was no correlation between systolic blood pressure during mental stress and ambulatory ischemia. Results of this study demonstrate that heart rate response during laboratory-induced mental stress correlates with magnitude of ischemia on ambulatory ECG monitoring in patients with coronary artery disease.
 ...
PMID:Increased heart rate response to laboratory-induced mental stress predicts frequency and duration of daily life ambulatory myocardial ischemia in patients with coronary artery disease. 757 20

Patients with hypercholesterolemia have impaired coronary and peripheral endothelial function. In patients with coronary artery disease, intracoronary acetylcholine infusion or mental stress causes paradoxical vasoconstriction, whereas lowering cholesterol restores endothelial function. The impact of lipid lowering by fluvastatin on myocardial perfusion in hypercholesterolemic patients with perfusion abnormalities was assessed by thallium-201 single photon-emission computed tomography (SPECT). A total of 22 patients were treated with fluvastatin (40 mg once daily) for 6 weeks, followed by 40 mg twice daily if low density lipoprotein cholesterol (LDL-C) levels were decreased by < or = 30%. During the 12-week treatment period, myocardial perfusion was measured by quantitative SPECT after standardized stress testing at baseline and after 12 weeks. Preliminary results for 17 male patients (mean age, 59.3 +/- 6.7 years) are presented here. LDL-C decreased from 191 +/- 26 to 146 +/- 28 mg/dL (p < 0.001). In ischemic segments myocardial perfusion increased by 30% (280 +/- 100 to 365 +/- 110 counts per matrix; p < 0.001). In normal segments perfusion increased by only 5% (451 +/- 74 to 473 +/- 69 counts per matrix; p < 0.005). The change in perfusion rate between ischemic and normal segments was significant (p < 0.005). In conclusion, LDL-C lowering with short-term fluvastatin therapy improved myocardial perfusion, especially in areas of ischemia. This suggests that improvement is due to functional restoration of coronary endothelium by fluvastatin, before anatomic regression of stenosis can occur following long-term treatment.
 ...
PMID:Improvement of myocardial perfusion by short-term fluvastatin therapy in coronary artery disease. 760 86


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>