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

Laser myocardial revascularization has been shown to reduce mortality and infarct size after left anterior descending coronary artery (LAD) ligation in dogs. It has not been shown to improve myocardial contractility in acute ischemia. In this study a holmium-yttrium-aluminum garnet laser (wavelength, 2.14 microns) was used to create nontransmural myocardial channels from the endocardial surface in the ischemic regions of the canine left ventricle. Twelve mongrel dogs (6 controls, 6 laser myocardial revascularizations) underwent 90 minutes of LAD ligation followed by 6 hours of reperfusion. The ischemic region was determined by methylene blue injection during brief LAD occlusion. Laser myocardial revascularization averaged three channels per square centimeter in the ischemic region created using 12 J/channel (600 mJ/pulse, 10 Hz) before LAD ligation. Contractility was assessed from regional preload recruitable stroke work (RPRSW), using pairs of segment length ultrasonic transducers in the ischemic and the nonischemic regions. Two-dimensional echocardiography corroborated with segmental length findings. In control dogs, the ischemic region was dyskinetic during LAD ligation and reperfusion. Dyskinesis of the ischemic region during systole produced negative values for regional stroke work, and RPRSW was considered zero. In 4 of 6 laser-revascularized dogs, RPRSW remained positive in the ischemic region. Two dogs had intermittent dyskinesis. The difference between laser-revascularized and control dogs in ischemic region RPRSW was significant (p < 0.01 by Fischer's exact test).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prevention of acute regional ischemia with endocardial laser channels. 814 72

The report presents the results of EchoCG study in 81 patients with unstable stenocardia admitted in 6-24 hours from the onslaught pain. With the help of EchoCG the myocardial contractile function was defined and the segmental kinetics of left ventricular wall was registered with respect to four variants of unstable stenocardia courses: stenocardia occurred for the first time, progressive stenocardia, variational stenocardia and postmyocardial infarction stenocardia. During the EchoCG examination at the moment of anginal attack the significant increase in left ventricular end-diastolic volume and end-systolic volume and decrease of total ejection fraction were noted. Also, not infrequently the zones of dyskinesia are recorded indicative of ischemia of these segments, which commonly have transient character. With the progress of myocardial ischemia the abnormalities of left ventricular diastolic fraction appear which are determined with the help of Doppler-EchoCG. Thus, the use of EchoCG in diagnostics of patients with unstable stenocardia allows more reliably to define the degree of myocardial changes.
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PMID:[The use of echocardiography in examining patients with unstable stenocardia]. 836 49

There are no standard criteria for the diagnosis of myocardial ischemia in akinetic segments during dobutamine stress echocardiography (DSE). The aim of the study was to assess the relation between different responses of akinetic segments during DSE and ischemia assessed by thallium-201 single-photon emission computed tomography (SPECT). Dobutamine-atropine stress echocardiography with simultaneous stress-reinjection thallium-201 SPECT was performed in 67 patients with old myocardial infarction significant and coronary artery stenosis. Fourteen myocardial segments were matched for both DSE and SPECT. Ischemia on SPECT was defined as reversible thallium defects. In 257 akinetic segments, 4 patterns during DSE were identified: (1) biphasic response in 41 segments (16%), defined as improvement at low dose (5 to 10 microgram/kg/min) followed by worsening at high dose; (2) persistent akinesia in 155 segments (60%); (3) akinesia becoming dyskinesia in 39 segments (15%); and (4) sustained improvement in 22 segments (9%). Reversible thallium defects were detected in 21 segments (51%) in group 1, in 20 segments (13%) in group 2, none in group 3, and in 2 segments in group 4 (9%). The prevalence of reversible defects in biphasic segments was higher compared with other patterns (p <0.00001 vs groups 2 and 3, p <0.005 vs group 4). The ischemic perfusion defect score was significantly higher in group 1 than group 2. The positive predictive value of biphasic response for reversible thallium defects was similar to that of stress-induced dyssynergia in normal segments at rest (51% vs 58%). It is concluded that of the various responses of akinetic segments to dobutamine infusion, the biphasic response is associated with the highest prevalence and greatest severity of ischemic on thallium SPECT. Observation of contractile response at both low- and high-dose DSE is a valuable approach for the diagnosis of myocardial ischemia in akinetic segments.
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PMID:Relation between contractile response of akinetic segments during dobutamine stress echocardiography and myocardial ischemia assessed by simultaneous thallium-201 single-photon emission computed tomography. 864 45

Both the severity and duration of postischemic myocardial dysfunction ("stunned" myocardium) are unpredictable and may vary considerably between subjects that underwent apparently similar ischemic insults. To explain this heterogeneous response of the heart to ischemia and reperfusion, we investigated the determinants of stunning in conscious dogs. Twenty-five dogs were chronically instrumented for measurement of global and regional myocardial performance (wall thickening) and myocardial perfusion (coloured microspheres). A hydraulic occluder was positioned around the LAD coronary artery. Conscious dogs were subjected to acute coronary artery occlusions of predetermined duration (2, 5 and 10 min), followed by complete reperfusion. Multiple regression analysis identified the following variables as determinants of postischemic contractile recovery: 1) the duration of ischemia (p < 0.01),2) the amount of collateral perfusion (p = 0.01) and 3) left ventricular end-diastolic pressure during ischemia (p < 0.01). Neither the severity of regional dyskinesia during ischemia nor indices of global systolic hemodynamic performance correlated with the rate of recovery. Our data confirm that myocardial stunning relates primarily to the intensity of preceding ischemia. Variations in the preexisting level of collateral perfusion may result in markedly different recovery profiles. Except for LV end-diastolic pressure during ischemia, indices of global and regional cardiac performance fail to predict the severity of postischemic contractile failure.
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PMID:Ischemic event characteristics determine the extent of myocardial stunning in conscious dogs. 874 May 30

Precordial ST-segment depression (PSD) in inferior wall acute myocardial infarction (IAMI), especially when maximal in leads V4-V6, has been shown to portend a higher rate of heart failure and mortality. To better understand the pathophysiology behind this phenomenon, we evaluated patients with a first IAMI by echocardiography 48-72 h after the acute event, using segmental scoring (0 = normal to 3 = dyskinesia) of left ventricle wall motion, and a dichotomous assessment of right ventricle involvement. Patients were categorized into 3 groups: I = no PSD (n = 14); II = maximal PSD in leads V1-V3 (n = 28); III = maximal PSD in leads V4-V6 (n = 8). As compared with group I, patients in groups II-III had more severe wall motion abnormalities in inferior segments (1.36 +/- 0.97 vs. 2.19 +/- 1.74, p = 0.04), and a similar trend for posterior and lateral segments (1 +/- 1.75 vs. 2 +/- 2.41, p = 0.11), translating into a worse total left ventricle score (2.36 +/- 2.34 vs. 4.25 +/- 4.05, p < 0.05). Frequency of right ventricle involvement was similar in patients with and without PSD (6 (43%) vs. 9 (25%), p = 0.37). Segmental scores for groups I, II, and III, respectively, were not different for inferior (1.36 +/- 1, 2.25 +/- 1.82 and 2 +/- 1.51, p = 0.24), posterior and lateral (1 +/- 1.75, 1.96 +/- 2.32 and 2.13 +/- 2.9, p = 0.38), and septal, anteroseptal and anterior segments (0 +/- 0, 0.04 +/- 0.19 and 0.13 +/- 0.35, p = 0.28). Right ventricle abnormalities occurred in 43, 21 and 38% of patients in groups I, II and III, respectively, p = 0.3. Thus, IAMI with PSD is associated with worse left ventricle wall motion. However, since patients with maximal PSD in leads V4-V6 do not have greater wall motion abnormalities or higher rate of right ventricle involvement, their poorer prognosis cannot be explained by worse systolic dysfunction. We propose that maximal PSD in leads V4-V6 reflects transient diffuse ischemia and altered diastolic distensibility due to extensive coronary artery disease, causing increased left ventricle end-diastolic pressure.
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PMID:Pathophysiology of precordial ST-segment depression in inferior wall acute myocardial infarction: an echocardiographic appraisal. 919 31

Dyskinesia is frequently seen in neurological disorders affecting the basal ganglia. Iminodipropionitrile (IDPN) produces a somewhat similar motor syndrome in rodents, one that is a possible model for dyskinesia. Because in previous studies the compound (N-[2-hydroxy-3-(1-piperidinyl) propoxy]-3 pyridine-carboximidoyl-chloride) (Bimoclomol, BRLP-42) was shown to provide protection against IDPN-induced retinopathy; we investigated the effect of BRLP-42 on IDPN-induced motor changes and on IDPN-induced cerebral amino acid level changes in rats and mice. IDPN had a biphasic effect on motor activity in C57BL/6 mice: it was a depressant for 24 days and a stimulant after 30 days. Bimoclomol inhibited the motor depressant effect and enhanced the stimulatory effect of IDPN in this mouse strain. In BALB/cBy mice and Sprague Dawley rats IDPN produced persistent vertical head movements and changes in the level of glutamic acid in brain. Bimoclomol reduced the effect of IDPN on head movements and blocked the effect on cerebral glutamate; by itself it had no effect on motor activity in either species. Bimoclomol inhibited ischemia-induced [3H]norepinephrine release from rat hippocampal slices. Our findings indicate that Bimoclomol could have a beneficial effect on some dyskinesias, and on drug-induced vertical head movements.
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PMID:Effect of bimoclomol (N-[2-hydroxy-3-(1-piperidinyl) propoxy]-3 pyridine-carboximidoyl-chloride) on iminodipropionitrile-induced central effects. 1009 20

The purpose of this study was to compare 2 different techniques--dobutamine-atropine stress echocardiography (DSE) and dual-isotope simultaneous acquisition (technetium-99-m-tetrofosmin/fluorine 18-fluorodeoxyglucose) single-photon emission computed tomography (DISA-SPECT)--for assessment of viable myocardium. One hundred ten patients (mean age 55 +/- 9 years) with left ventricular (LV) dysfunction (mean LV ejection fraction 27 +/- 13%) underwent both DISA-SPECT and DSE. A 16-segment scoring model was adopted for both techniques. Four types of wall motion during DSE were assessed: (1) biphasic, improvement at low dose (10 microg/kg/min) with worsening at high dose; (2) worsening, deterioration without initial improvement; (3) sustained, persistent or late improvement; and (4) no change. Viability criteria were biphasic, worsening, and sustained improvement with DSE. Viability criteria with DISA-SPECT were normal perfusion and metabolism (normal), concordantly mildly reduced perfusion and metabolism (subendocardial scar), or severely reduced perfusion and increased metabolism (mismatch). Myocardium was considered nonviable with DSE in case of unchanged wall motion, or moderate reduction or absence in both technetium-99m-tetrofosmin perfusion and fluorodeoxyglucose uptake with DISA-SPECT. Of 1,756 of 1,760 analyzable LV segments, 1,373 (78%) had severe wall motion abnormalities at baseline (severe hypokinesia, akinesia, or dyskinesia). Of these abnormal segments, 282 (21%) were considered viable during DSE (63 [5%] with biphasic response, 47 [3%] with ischemia, and 172 [13%]) with sustained improvement, whereas 1,091 (79%) were considered nonviable. With DISA-SPECT, 396 (29%) segments were considered viable (312 [23%] with matched perfusion/metabolism and 84 [6%] with mismatch), whereas 977 segments (71%) were considered nonviable. Both techniques showed agreement for viability in 201 segments and 896 were concordantly classified as nonviable. Disagreement was present in 276 segments of which 195 (71%) were nonviable with DSE and viable with DISA-SPECT. Overall agreement between the 2 techniques was 81% (kappa 0.46) in a subgroup of patients with an ejection fraction <25% 78% (kappa 0.39). Thus, DSE and DISA-SPECT show good agreement for assessing viable myocardium not influenced by resting ejection fraction. DSE underestimated the amount of viable tissue compared with DISA-SPECT.
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PMID:Dobutamine stress echocardiography and technetium-99m-tetrofosmin/fluorine 18-fluorodeoxyglucose single-photon emission computed tomography and influence of resting ejection fraction to assess myocardial viability in patients with severe left ventricular dysfunction and healed myocardial infarction. 1042 27

In patients with a previous myocardial infarction, controversy exists regarding the significance of postexercise ST-segment elevation in the infarct-related leads. Although usually admitted to be a sign of left ventricular dysfunction or myocardial aneurysm, other studies however have related this finding to transient myocardial ischemia and to the presence of jeopardized but viable myocardium in the infarct area. The aim of the present study was to assess the significance of postexercise ST-segment elevation in Q-wave leads as a marker of transmural ischemia or left ventricular dysfunction in 36 consecutive patients, 16 with exercise-induced ST-segment elevation in infarct-related leads. Patients were evaluated by treadmill exercise testing, coronary angiography and ventriculography, thallium-201 tomographic scintigraphy and radionuclide ventriculography within 3 months of the first myocardial infarction. Sixteen patients (group I) had exercise-induced ST segment elevation and 20 (group II) postexercise inversion, no change or pseudonormalization of the T wave in infarct-related leads. The study showed no difference in infarct-related artery, vessel disease or luminal diameter stenosis in groups I and II. The overall agreement between ST shifts and myocardial perfusion in the infarct area was 30.56% with a kappa coefficient of -0.33 (p = NS). The overall agreement between ST shifts and wall motion abnormalities was 69.44% with a kappa coefficient of 0.39 (p < 0.01), stress-induced ST-segment elevation being associated with severe wall contractile disorders in 85% of the patients. In conclusion stress-induced ST-segment elevation in Q wave leads, although not a marker of wall motion abnormalities, is associated with akinesia or dyskinesia of the left ventricular wall.
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PMID:Role of myocardial ischemia and left ventricular wall motion abnormalities as contributory factors in the genesis of exercise-induced ST-segment elevation in Q-wave myocardial infarction. 1054 77

The paper presents current views on ischemia-reperfusion and mechanisms of its development. Their role in the development of the hibernating myocardium is shown. Possible clinical manifestations of these conditions and currently available diagnostic techniques are assessed. The purpose of the study was to detect the hibernating myocardium in patients with coronary heart disease (CHD) and arterial hypertension (AH). The study enrolled 13 patients with CHD and AH. Myocardial biventricular scintigraphy was conducted in patients before treatment and during acute coronarolytic test. Prior to treatment, all the patients were found to have reversible asynergy, left and right ventricular myocardial hypo- and dyskinesia caused by the hibernating myocardium. The drug test revealed better segmental contractility than the baseline one due to the fact that the function of asynergic segments recovered and fraction ejection increased. The findings suggest that the hibernating myocardium is diagnosed in patients with CHD and AH without myocardial infarction, which is of importance in determining treatment policy and prognosis in these patients.
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PMID:[Diagnosis of the hibernating myocardium in early stages of heart failure in patients with coronary heart disease]. 1083 85

Echocardiography was made in 330 patients with ischemic stroke. Group 1 consisted of 72(21.8%) patients with hemodynamic stroke, the rest 258(78.2%) patients (group 2) had other pathogenetic subtypes of stroke. Chronic cardiac pathology was represented by postinfarction cardiosclerosis (38.9 and 17.8% for groups 1 and 2, respectively, p < 0.001) and continuous atrial fibrillation (15.3 and 15.1%, respectively, p > 0.05). Stroke volume of the left ventricle (LV), cardiac output and ejection fraction of the LV were significantly less than in group 2 and in control group but within normal range. The number of group 1 patients having local LV dyskinesia and transitory painless myocardial ischemia was significantly higher than in group 2 (p < 0.001). Painless ischemia correlated with local dyskinesia of the LV (p < 0.02). As transitory myocardial ischemia may deteriorate LV contractility and provoke excessive fall of blood pressure, local LV dyskinesia caused by postinfarction changes seems to be a principal and stable echocardiographic sign of developing hemodynamic stroke.
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PMID:[Echocardiographic alteration in patients with hemodynamic stroke]. 1189 16


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