Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To compare the hemodynamic, antiischemic, metabolic, and neurohumoral effects of intravenous esmolol (beta 1 blocking agent) and gallopamil (verapamil-like calcium channel blocker), 14 patients with angiographically proven CAD and reproducible ST segment depression were studied at rest and during exercise under control conditions and after an intravenous bolus injection of esmolol (0.5 mg/kg/1 min, followed by an infusion with 0.2 mg/kg/min) or gallopamil (0.025 mg/kg/3 min). In contrast to gallopamil, esmolol significantly reduced systolic blood pressure (175.7 vs. 160 mm Hg) and heart rate (107.4 vs. 96.9 min-1) during exercise as well as cardiac output (11.57 vs. 9.38 l/min) and significantly enhanced systemic vascular resistance both at rest (1241 vs. 1479 dynes.s.cm-5) and during exercise (805 vs. 947 dynes.s.cm-5). On the other hand, exercise filling pressures and lactate levels (3.66 vs. 3.05 mmol/l) were significantly reduced by gallopamil only. Thus, the significant improvement of exercise tolerance by both esmolol and gallopamil is based on different mechanisms of action: esmolol improves myocardial ischemia by appreciably reducing myocardial oxygen consumption, whereas gallopamil primarily improves oxygen supply and ventricular performance. Plasma catecholamines, atrial natriuretic factor, and aldosterone levels as well as plasma renin activity were identically influenced by esmolol and gallopamil, respectively. A reflex activation of the sympathetic system did not occur.
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PMID:[Anti-ischemia effects of gallopamil and esmolol in an intra-individual comparison in patients with coronary heart disease]. 791 67

Aim of this study was to analyze the cardiovascular response to graded physical exercise in patients who have undergone cardiac transplantation and to assess the ability of exercise stress testing in early detection of coronary artery disease. We studied 114 transplanted subjects (100 men and 14 women, mean age 46.6 +/- 11.3 years), who performed exercise stress testing 6 months after bypass and then every 6 (+/- 1) months during a 5-year follow-up. Variations of hearth rate (HR), systolic blood pressure (SBP), heart rate-pressure product (RPP) values and exercise stress tolerance were studied both in basal and maximum workload conditions. Mean HR values at basal conditions (103.9 +/- 11.3 b/min at 6 months and 89 +/- 12.7 b/min at 60 months, p < 0.05) and maximum workload tolerance (67.7 +/- 20.4 W at 6 months and 100 +/- 17 W at 60 months, p < 0.05) were significantly different at the beginning and at the end of follow-up. SBP values both at basal conditions and at peak exercise had always been constant. Exercise was stopped for leg muscle fatigue in 92% and dyspnea in 7% of the subjects; isolated T-wave and ST segment changes were found in 29.8% and in 10.5% of the patients respectively, whereas 11.4% exhibited both ST-T variations. Angiographic examination (performed in 80/114 patients) showed significant coronary disease (stenosis > 50%) in 8, coronary atherosclerosis (CAD) of minor degree in 4 and provoked spasm in 2 subjects. In this subgroup exercise stress testing induced ischemic ECG changes (ST segment depression > or = 1 mm) without angina in 1 patient, ST-T segment variations only in 5 and no electrocardiographic alterations (negative tests) in 2 patients. Four subjects with CAD and 1 with coronary spasm induced by angiography showed isolated ST segment and T-wave changes. Our work demonstrated that exercise stress testing plays a relevant role in the study of the denervated heart response to dynamic exercise. The rise in workload tolerated, observed in our population, seems to be related to time elapsed from surgery, improvement in clinical conditions, psychological stability and patient's confidence in his own abilities. The tolerance to exercise 6 months after graft seems to predict the quality of performance in the following tests. Our angiographic results reveal a low sensitivity of the exercise stress test in detecting CAD in this population according to traditional electrocardiographic criteria for myocardial ischemia.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[The ergometric test after a heart transplant: its usefulness and limits]. 808 12

The documentation of abnormalities related to myocardial ischemia, whether symptomatic or silent, is of central importance. Whenever this information is available, it should be used in the overall assessment of the patient at risk for adverse outcome. The level of concern for treatment of CAD should be based on the risk implications associated with the ischemia-related abnormalities detected during objective testing rather than on the presence or absence of pain. The exercise stress test is still the single most useful test to begin the evaluation of a patient with an analyzable ST segment. In persons suspected of having CAD, the detection of ischemic-type ST-segment depression, at a low workload (e.g., < 120 beats/min or < 6.5 METS) of > 2 mm magnitude or persisting for more than 6 min implies high risk for adverse outcome. Asymptomatic ischemia during everyday activities, detected by Holter monitoring, in the high-risk patient, most probably adds additional risk beyond the risk of an abnormal stress test alone. Left ventricular imaging by two-dimensional echocardiography, RNA, angiogram, vest, etc, showing an ejection fraction > or = 40%, reversible wall motion abnormalities in multiple regions and redistribution defects or a failure to increase ejection fraction during exercise even if the patient remains asymptomatic, also imply high risk. The presence of any of these abnormal findings, regardless of symptoms, should therefore prompt as high a degree of concern as with ischemia-related signals associated with pain. Thus any therapy chosen should be directed toward elimination of transient ischemia, not just relief of symptoms that may or may not be ischemia related. If this course is chosen, the efficacy of the therapeutic regimen and possible progression of CAD should be assessed with follow-up testing for ischemia. We believe that risk factor modification and aspirin should be considered for most, if not all, patients in whom ischemia, silent or symptomatic, is suspected or detected. If symptoms or ischemia suggesting low risk is present, anti-ischemic medical therapy may be considered, but follow-up is advised. If a high-risk ischemic signal, even without symptoms, is detected, medical therapy should be used to attempt to modify the signal. If the ischemic signal suggesting high risk persists despite medical therapy, revascularization should be considered. Until additional data from large clinical trials are available, this approach appears to have the greatest likelihood of modifying the adverse outcome of CAD.
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PMID:Silent myocardial ischemia. 834 34

To examine the effects of hemodialysis on the electrocardiogram, 87-lead body surface maps were performed in 38 patients with chronic renal failure, before and after hemodialysis. The patients were divided into two groups; 16 patients with coronary artery disease (CAD group), and 22 patients without ischemic heart disease (control group). Three maps were analyzed, QRS isopotential maps, isochrone maps, and QRS isointegral maps. Parameters measured were maximal R wave voltage (Peak R), minimal QRS wave voltage (Peak S), maximal ventricular activation time (VATmax) and QRS duration (QRSd). In the control group, Peak R and Peak S increased but VATmax decreased after hemodialysis. There were negative correlations between the changes of body weight and the changes in Peak R (r = -0.67, p < 0.01) and Peak S (r = -0.87, p < 0.001), although there were no correlations between changes in left ventricular diastolic dimension and the changes in Peak R and Peak S. In the CAD group, Peak S increased but Peak R and VATmax did not change significantly. There were negative correlations between the change of body weight and the change of Peak S (r = -0.73, p < 0.01). The most pronounced changes in mean QRS isointegral maps on hemodialysis were an increased magnitude of positivity in the control group and negativity in the CAD group on the anterior thorax. These findings suggested that the increase in the QRS amplitude after hemodialysis was influenced by the changes of the conductivity of extracardiac thorax and the relative heart position to the chest wall rather than myocardial ischemia or ventricular conduction delay.
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PMID:Effects of hemodialysis on body surface maps in patients with chronic renal failure. 836 84

OBJECTIVE--To test the hypothesis that the complement system may be activated in patients with type II diabetes and CAD. RESEARCH DESIGN AND METHODS--The plasma C3d concentration was measured in 106 type II diabetic patients and 25 nondiabetic control subjects. The patient group was subdivided according to AER, and the groups were adjusted for age, sex, and known duration of diabetes. For the assignment to a given subgroup, normoalbuminuria was defined as AER < 15 microns/min, microalbuminuria as AER 16-250 micrograms/min, and macroalbuminuria as AER > 250 micrograms/min. The presence or absence of coronary disease was assessed through clinical examination, ECG, and coronary angiography. An RIA system was used for measurement of urinary albumin levels, and the plasma C3d concentrations were measured by ELISA. RESULTS--Within each of the AER-defined subgroups, the plasma C3d levels were significantly higher in patients with IHD than in those without. Thus, in the normoalbuminuric group, plasma C3d levels were 16.3 AU/ml (95% CI 13.9-19) in patients with IHD vs. 11.6 AU/ml (95% CI 10.5-12.7) in those without (P < 0.001). The corresponding data for the microalbuminuric and macroalbuminuric groups were 21.8 (95% CI 18.1-26.3) vs. 13.6 (95% CI 12.3-15.1) and 31.6 (95% CI 24.9-40) vs. 17.5 (13.6-22.6) AU/ml (P < 0.01), respectively. Patients with IHD also had significantly higher plasma C3d levels than normal control subjects, regardless of AER subgroup. A multiple logistic regression analysis demonstrated an association between the plasma C3d concentration and IHD and AER. CONCLUSIONS--Activation of the complement system may play a role in the development of macrovascular disease in type II diabetes.
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PMID:Plasma C3d levels and ischemic heart disease in type II diabetes. 843 15

A total of 110 patients suspected with CAD who had symptoms or ECG abnormalities were enrolled in the stress-rest ECG gated SPECT one day protocol using 99mTc-MIBI. All the patients underwent symptom-limited exercise testing and 250 MBq of MIBI was injected at peak exercise. Exercise perfusion SPECT images were reviewed by two trained doctors to classify into three groups; normal, equivocal and abnormal. Patients with normal stress image (n = 53) did not receive the resting study. On the other hand, those with equivocal (n = 20) and abnormal (n = 37) stress images performed resting study, including gated SPECT. Of 20 equivocal cases, 16 patients showed unchanged resting perfusion. All of these had normal wall motion. The remaining 4 patients showed improved resting perfusion, indicating presence of myocardial ischemia. Of 37 abnormal cases, 12 patients showed improved resting perfusion, whereas 25 patients showed unchanged resting perfusion. Cardiac events were more often observed in abnormal cases, especially those associated with myocardial ischemia, while good prognosis was obtained in normal cases. Values of this protocol are (1) Patients with normal stress images need no resting study. (2) All the procedure can be completed in one day. (3) Both cardiac function and perfusion can be obtained with gated SPECT. These data indicates that this protocol is valuable for screening patients suspected with CAD.
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PMID:[Value of stress-rest ECG gated SPECT one day protocol using 99mTc-MIBI]. 858 19

Positron emission tomography (PET) offers the unique capability of measuring specific flow (flow per unit of mass) in man by means of a regional, tridimensional, noninvasive approach. Using PET, myocardial perfusion abnormalities secondary to microvascular disorders have been investigated in arterial hypertension (AH), dilated and hypertrophic cardiomyopathy (CM), as well as in ischemic heart disease (CAD). In AH, regional perfusion at rest is within the normal range, while the coronary reserve and flow response to increase in metabolic demand are blunted. These flow abnormalities are independent of the degree of cardiac hypertrophy and the severity of AH; appropriate anti-ipertensive therapy is able to improve the perfusion abnormalities after long term treatment, independently of the effect on myocardial hypertrophy. Both dilated and hypertrophic CM demonstrate abnormal vasodilating capability, which has been shown to be present in the subclinical form of dilated DM; the reduction of coronary reserve is not related to the presence and extent of the hemodynamic impairment in dilated CM, and involves also nonhypertropied myocardium in asymmetric hypertrophic CM. These findings indicate a primary involvement of coronary microcirculation in non advanced forms of dilated and hypertrophic CM. Finally, in patients with CAD, myocardial territories supplied by angiographically normal coronary arteries show abnormal coronary reserve and flow during pacing tachycardia, indicating that, even in absence of epicardial coronary artery obstruction, microcirculation is impaired in subjects with coronary atherosclerosis. This abnormality can smooth perfusion differences between control and jeopardized regions. Accordingly, the absence of a perfusion defect during stress might indicate the presence of either a non significant stenosis or a diffuse impairment in microcirculatory function. Nuclear perfusion imaging with conventional perfusion tracers does not allow measurements of absolute blood flow, rather it provides an estimation of perfusion inhomogeneities. Although the agreement with the angiographic documentation of coronary artery disease has been frequently considered to characterize the diagnostic reliability of these techniques, the evaluation of myocardial perfusion provides an independent tool for the functional assessment of patient with heart disease. The possibility to obtain measurements of regional myocardial blood flow, provided by positron emission tomography, helps to identify the mechanisms affecting flow regulation in the myocardium. This tool thus provides a new rationale for the application of perfusion imaging, to obtain a more precise characterization of these patients, beyond the agreement with the morphological angiographic picture.
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PMID:The role of coronary microvascular dysfunction in the genesis of cardiovascular diseases. 868 Oct 18

High-dose dipyridamole transesophageal stress echocardiography has recently been proposed as a useful and safe method to assess myocardial ischemia in patients with poor transthoracic acoustic window. It has also been shown that transesophageal echocardiography (TEE) allows the study of coronary blood flow reserve (CBFR) in the left anterior descending artery (LAD). The aim of our study was to assess whether the morphologic information and pathophysiologic data on CBFR and myocardial ischemia can be collected by a single stress TEE without comprimizing its feasibility, safety and accuracy. We studied, 29 patient with known or suspected CAD (previous myocardial infarction or angina) (Group A), and as a control group, we studied 11 patients with mitral disease or mitral prostheses (Group B). All patients underwent the coronary angiography. None of Group B patients showed significant coronary artery stenosis (> 70%). In baseline conditions left ventricular wall motion and LAD coronary blood flow velocity (CBFV) were also evaluated. The following CBFV parameters were measured: maximal diastolic velocity (MaxDV), mean diastolic velocity (MnDV), maximal systolic velocity (MaxSV), mean systolic velocity (MnSV). The ratios of dipyridamole to rest maximal and o mean to diastolic velocities (MaxDV-Dip/Max DV-rest; MnDv-Dip/MnDV-rest) were measured as indexes of CBFR. No side effects were observed and the test could be completed in all patients (feasibility 100%). Wall motion analysis was adequate in all patients (feasibility 100%). Comparison between wall motion analysis was obtained and angiographic findings shown that the overall sensitivity and specificity of TEE were 84% and 93% respectively. Sensitivity for one, two and three vessel disease was 60%, 70% and 100%, respectively. LAD CBFV was adequately recorded in 85% of patients. CBFR parameters showed a significant difference between the two groups (Max DV-Dip/Max DV-rest: 1.67 +/- 0.7 vs. 2.73 +/- 0.6, P < 0.001); comparison between Group B patients and those of Group A with angiographically documented LAD stenosis showed a statistically significant difference in CBFR parameters (MaxDV-Dip/MnDV-rest, 2.73 +/- 0.6 vs. 1.65 +/- 0.7, P < 0.001, MnDV-Dip/MnDV-rest, 2.56 +/- 0.5 vs. 1.69 +/- 0.6 < 0.001). We conclude that transesophageal stress echocardiography is a useful method to study CAD and that it is possible to assess both morphologic and pathophysiologic information during a single examination.
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PMID:Usefulness of dipyridamole transesophageal echocardiography in the evaluation of myocardial ischemia and coronary artery flow. 891 17

A decrease in cardiac parasympathetic tone is a recognized finding in patients with ischemic heart disease, correlating closely with disease severity and overall survival. The aim of this study was to assess whether transdermal scopolamine (Tds), which increases parasympathetic tone in healthy volunteers, increases vagal tone in patients with severe CAD and whether it might have an antiischemic effect. Fifteen patients (10 men, aged 55 +/- 8 years) with three-vessel CAD, but with no prior MI and preserved ventricular function, underwent 24-hour Holter monitoring and exercise testing before and after wearing a scopolamine patch for 24 hours. Time-domain measures of heart rate variability (HRV) and the total number and duration of ischemic episodes were obtained from the Holter recordings for each patient. Tds significantly (P < 0.05) increased the values of all HRV measures. Tds also reduced the total number of ischemic episodes (from 273 to 159, P < 0.05) and their total duration (from 136 to 46 min per patient, P < 0.05). Tds also increased treadmill exercise duration from 293 +/- 101 to 345 +/- 95 seconds (P < 0.05) and the time to 1-mm ST depression from 177 +/- 105 to 244 +/- 128 seconds (P < 0.02), while maximum ST depression was reduced from 2.86 +/- 0.6 to 2.3 +/- 0.3 (P < 0.05). No significant side effects were observed. Tds modifies the autonomic balance in patients with severe CAD toward a condition associated with a better prognosis. It may also be useful as an adjunctive treatment for ischemic heart disease.
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PMID:Effect of transdermal scopolamine on heart rate variability in patients with severe coronary heart disease. 894 58

Endothelin (ET), the most potent endogenous vasoconstrictor with mitogenic potency, is generated from its precursor big-endothelin (BET) in a proteolytic process and discussed as a pathogenetic factor in coronary artery disease and in the acute coronary syndromes. Several studies documented elevated plasma endothelin concentrations in acute myocardial infarction, but conflicting results were reported in patients with stable and unstable angina. Only few studies determined big endothelin, although it half-life and plasma concentrations are higher in comparison to endothelin. ET and BET levels (Radioimmunoassay, Biomedica GmbH, Vienna) were determined in patients with stable angina (SAP, n = 20), unstable angina (IAP, n = 12), acute myocardial infarction (AMI, n = 12) and healthy subjects (NP, n = 11). The concentrations of ET and BET (median (minimum-maximum) in fmol/ml) of the patients with stable angina (SAP: ET 0.7 (0.3-1.1); BET 1.7 (0.7-2.9)), unstable angina (IAP: ET 1.0(0.5-1.7); BET 2.5 (1.3-4.1)) and acute myocardial infarction (AMI: ET 1.2 (0.6-2.3); BET 3.6 (3.2-5.3)) showed a significant difference compared to controls (NP: ET 0.5 (0.4-0.7); BET 1.4 (1.1-1.7)) (SAP vs. NP: ET p < 0.01; BET p < 0.05; IAP and AMI vs. NP: ET and BET p < 0.001). Also, the concentrations of the peptides differed significantly dependent on the clinical severity of coronary artery disease (AMI vs. SAP: ET and BET p < 0.001; AMI vs. IAP: BET p < 0.05; IAP vs. SAP: ET p < 0.05; BET p < 0.01). Twelve of 15 patients with big endothelin concentrations over 3 fmol/ml suffered acute myocardial infarction. Seven of 12 patients with AMI showed elevated ET and BET concentrations before the increase of creatinecinase. There was no correlation between number of risk factors per patient, cholesterin and subfractions, severity of CAD classified in one-two-three-vessel disease or coronary score according to modified criteria of the American Heart Association (AHA). We conclude that in patients with coronary artery disease endothelin and big endothelin levels are elevated and related to the clinical and not to the morphological severity of coronary artery disease. Big endothelin is the more sensitive parameter in comparison to endothelin and indicates a severe course of myocardial ischemia in patients with unstable angina. The development of assays with the possibility of a quick determination of the peptides may be valuable for risk stratification of acute coronary events.
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PMID:[Endothelin and big endothelin in coronary heart disease and acute coronary syndromes]. 903 1


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