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 determine whether myocardial ischemia is accompanied by variation in heart rate and/or blood pressure, ST-segment analysis on Holter-ECG and ambulatory blood pressure monitoring was performed in 78 patients (64 males/14 females) with essential hypertension. Thirteen out of 55 patients (24%) with angiographically proven coronary artery disease (CAD) showed ST-segment depression (ST-D; group A pos). We observed 41 ST-D (1-11 ST-D; median: 2) lasting from 1 min to 70 min 15 s (median: 4 min 42 s) and an average depression of 185 +/- 48 mV. In comparison, in 6 of 23 patients (26%) with a normal angiogram 24 ST-D (1-10; median: 3; group B pos), which showed longer duration (1 min to 109 min 20 s; median: 11 min 10 s) and less depression (137 +/- 47 mV) have been found. 73.3% of all ST-D in group A pos and all in group B pos were preceded by an average increase in heart rate of 13 bpm. Exclusively, 12 episodes of ischemia (29.3%) in patients with CAD and 8 (33.3%) in patients without CAD were accompanied by an increase in blood pressure, which was more distinct in group A pos. Transient myocardial ischemia can be shown in hypertensive heart disease unrelated to CAD. A clear correlation between an increase in blood pressure and ST-D could not be proven.
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PMID:[Blood pressure variability and transient myocardial ischemia in patients with essential hypertension]. 151 10

To evaluate the clinical significance of asymptomatic ischemic heart disease, exercise electrocardiography and stress myocardial scintigraphy were performed. These were correlated with symptoms during exercise tests and histories of myocardial infarction (MI). The study subjects consisted of 70 patients with coronary artery disease, including 34 with MI, and 36 without MI but with angina pectoris. Stress tests were performed using bicycle ergometer under electrocardiographic monitoring throughout the test. Transient myocardial ischemia was confirmed by perfusion defects on thallium myocardial imaging demonstrated immediately after exercise, but not 3 hours after the stress test. Asymptomatic ST depression was observed in 18 of 34 patients with MI (53%) and in 21 of the 36 patients with angina (58%); however, transient myocardial perfusion defects were confirmed in 61% of the patients with MI (11 of 18 patients), but in only 33% of those with angina (7 of 21 patients). The difference was statistically significant (p less than 0.05). It was suggested that there are some differences in the clinical significance of asymptomatic ST depression between the patients with MI and those without MI but with angina pectoris.
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PMID:[Stress myocardial scintigraphy in coronary artery disease: its clinical significance]. 181 79

The availability of ambulatory ECG monitoring allows identification of transient myocardial ischaemia, the clinical relevance of which is currently being investigated. Ninety-four consecutive patients with ischaemic heart disease and a positive exercise test (greater than or equal to 1 mm ST-segment depression) were studied to evaluate the prevalence of transient myocardial ischaemia (either painless or painful) during 24-h dynamic electrocardiogram (ECG) and the clinical, angiographic and ergometric variables predicting its appearance. Two-hundred-and-eighty-one episodes of transient electocardiographic myocardial ischaemia were recorded in 69 patients (73.4% of all patients). Transient myocardial ischaemia was more frequent, although not significantly so, in patients with diabetes, with previous myocardial infarction, or with multivessel disease. When tested by multivariate analysis, neither the clinical variables nor the severity of coronary artery disease allowed prediction of the occurrence of transient myocardial ischaemia during dynamic ECG. The duration of exercise testing up to the ischaemic threshold (ST-segment depression = 1 mm) and the peak heart rate during exercise were more accurate predictors of transient myocardial ischaemia (P = 0.019 and 0.012 respectively). Patients with transient myocardial ischaemia had a lower ischaemic threshold (355 +/- 175 vs 498 +/- 150 s, mean +/- SD, P = 0.001) despite a lower peak heart rate (129 +/- 18 vs 137 +/- 12 beats min-1, P = 0.047) than patients without transient myocardial ischaemia. In conclusion, exercise testing may help select patients for examination by dynamic ECG.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Transient myocardial ischaemia: a multivariate analysis on clinical, angiographic and ergometric variables. 231 14

We wanted to determine whether there are episodes of myocardial ischemia in hypertensive patients with a normal coronary angiogram. ST-segment analysis on 24-h-Holter ECG was performed in 35 patients (18 males/17 females; mean age 54.6 +/- 10.4 years) with essential arterial hypertension (systolic/diastolic blood pressure 189.7 +/- 29/99.5 +/- 15 mm Hg). Left ventricular muscle mass (LVMM), enddiastolic volume (EDV), and the relation of mass to volume (M/V) were measured by ventriculography. Stenosis of coronary vessels was excluded by angiography in all patients. In 16 of 35 patients we observed 6.63 +/- 6.73 episodes of transient myocardial ischemia (ST-segment depressions greater than or equal to 1 mm, duration of the episode greater than or equal to 1 min). The duration of the episodes was 29.3 +/- 58.1 min, the maximal ST-segment depression 1.6 +/- 0.6 mm. In 95% of the episodes the patients did not experience any angina pectoris ("silent ischemia"). The degree of left ventricular muscle mass did not differ in hypertensive patients with and without transient myocardial ischemia (185.2 +/- 48.3 vs 227.1 +/- 71.5 g/m2). Systolic wall stress i.e. afterload was significantly higher in hypertensive patients with ST-segment depressions than in those without. In conclusion, these results demonstrate that transient myocardial ischemia often occurs in hypertensive patients. It seems that left ventricular hypertrophy by itself (myocardial factor) does not play a major role. Transient myocardial ischemia occurs mainly in hypertensive patients with eccentric myocardial hypertrophy i.e. low mass-volume ratio and high systolic wall stress. Accordingly, the occurrence of transient myocardial ischemia in hypertensive patients seems to be dependent on the myocardial energy demand.
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PMID:[Transient myocardial ischemia in hypertensive patients]. 252 20

Myocardial ischemia results in altered left ventricular (LV) diastolic compliance, reflected by an abnormal mitral inflow pattern on Doppler echocardiography. To investigate the relationship of Doppler echocardiography and regional myocardial systolic function during dipyridamole infusion, we evaluated transmitral flow changes detected by pulsed Doppler technique during a high-dose dipyridamole echocardiography test (DET, two-dimensional echo monitoring with dipyridamole infusion, up to 0.84 mg/kg over 10 min). The DET response produced two groups: group 1 (34 patients) with negative DET, and group 2 (35 patients) with positive DET, defined as the development of a newly onset LV regional asynergy. The E/A values overlapped at baseline (1.07 +/- .32 vs .92 +/- .22; p = NS) but differed at peak changes (.92 +/- .26 vs. 75 +/- .25; p less than .01). Heart rate changes could not account for the observed Doppler changes, since the values of R-R interval were similar in the groups, both basally (.927 +/- .226 vs .867 +/- .143 s; p = NS) and at peak dipyridamole (.754 +/- .100 vs. 681 +/- .112; p = NS). Transient myocardial ischemia induced by dipyridamole administration is accompanied by changes in transmitral flow, which consist of an increase in the relative atrial contribution to LV filling, possibly owing to an acute impairment in LV relaxation.
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PMID:Transmitral flow changes during dipyridamole-induced ischemia. A Doppler-echocardiographic study. 270 60

Transient myocardial ischemia is more frequently silent than accompanied by angina. The frequency of ischemia varies markedly from day to day, so that in order to accurately define the total ischemic burden, it may be necessary to quantitate ischemic episodes for periods longer than 24 hours. Therefore, a programmable, digital device was developed for long-term, interactive, ambulatory monitoring of the electrocardiogram, which uses variations in a time-averaged ST level as an indicator of myocardial ischemia. The electrocardiographic signal is digitized at 256 Hz and analyzed by an algorithm. If ST depression is planar or downsloping and persists for more than 40 seconds, and if the ST depression is equal to or more than a user-programmed threshold, the device marks the onset of an ischemic event and times it. The algorithm has been validated by comparison of its analysis of the ST segment to human and computerized analyses of frequency-modulated Holter recordings and stress tests. To assess the feasibility and utility of long-term monitoring, patients with documented coronary artery disease were monitored continuously for 14-day periods. Of 26 patients enrolled, 8 completed a protocol for individualization of anti-ischemic therapy using transdermal nitroglycerin. Over 90% of ischemic episodes in this group of patients, all of whom had had a previous myocardial infarction, were silent. Treatment with 10 mg of transdermal nitroglycerin reduced the number of ischemic episodes by 59% and the duration of ischemia by 60% (p less than 0.001); there was no diminution in the effectiveness of treatment from week 1 to week 2.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Quantitation of transient myocardial ischemia by digital, ambulatory electrocardiography. 312 90

Transient myocardial ischemia, with attendant sympathetic hyperactivity, seems to play a major role in sudden cardiac death among patients with ischemic heart disease. Ventricular tachycardia (VT) and fibrillation (VF) are consistently and repeatedly elicited in cats by the interaction between a 2-minute occlusion of the left descending coronary artery and a 30-second stimulation of the left stellate ganglion. When three consecutive trials yield almost identical results, time alone will not modify the response and a given drug can be injected to test its efficacy with an internal control analysis. In 90 cats the efficacy of the following drugs was assessed: lidocaine (n = 11), mexiletine (n = 12), propafenone (n = 12), propranolol (n = 19), prazosin (n = 10), amiodarone (n = 14), and verapamil (n = 12). Class I antiarrhythmic drugs completely failed to afford protection and worsening of arrhythmia was observed in several instances. Propranolol and prazosin showed efficacy in approximately 80% and 60% of the animals, respectively. Amiodarone and verapamil completely prevented the onset of VT and VF. Protection from arrhythmias seems to be related to the combined presence of a noncompetitive adrenergic blockade associated with salutary effects on coronary circulation. These findings correlate with and help to explain the results of clinical trials in postmyocardial infarction patients. This model may help to provide a rational choice of antiarrhythmic drugs to be tested in clinical trials.
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PMID:The effect of antiarrhythmic drugs on life-threatening arrhythmias induced by the interaction between acute myocardial ischemia and sympathetic hyperactivity. 399 28

Transient myocardial ischemia in postoperative hypertension is relatively common with coronary artery bypass surgery. This study examines the effect of hypertension during reperfusion of transiently ischemic myocardium. The animal model was open chest pigs with myocardial ischemia induced by the occlusion of the left anterior descending coronary artery for 30 min followed by 2 hr of reperfusion. A normotensive control group was compared with animals rendered hypertensive with phenylephrine during the ischemic and reperfusion times. In the hypertensive group, systolic blood pressure was raised from 106 to 161 mm Hg and peripheral vascular resistance from normal to 3600 dyn-sec-cm-5. Regional left ventricular wall thickness, mitochondrial function, sarcoplasmic reticulum Ca2+ uptake, tissue calcium, water content, and hemorrhage were evaluated. Compared to controls the hypertensive group had (1) loss of systolic wall thickening with increased diastolic wall thickness in the reperfused zone, (2) intramyocardial hemorrhage in the area of reperfusion, (3) significant impairment of oxidative phosphorylation by mitochondria isolated from the reperfused zone, (4) a marked reduction in the rate of Ca2+ uptake by sarcoplasmic reticulum vesicles, and (5) an increase in ischemic tissue calcium. Thus, hypertension associated with revascularization of acutely ischemic myocardium may accentuate myocardial damage.
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PMID:The adverse effect of systemic hypertension following myocardial reperfusion. 660 May 6

Ambulatory ST-segment monitoring is a relatively new device in the evaluation of myocardial ischemia. The method is unique in allowing us to continuously examine the patient over an extended period of time in a changing environmental milieu. In survivors of acute myocardial infarction the prevalence of ambulatory or transient myocardial ischemia is lower than in patients with chronic, stable coronary artery disease. A greater proportion of ischemic episodes, however, are silent than in other subgroups with ischemic heart disease. Early after the infarction, transient myocardial ischemia exhibits a circadian variation with a peak activity occurring in the late evening hours. Patients with non-Q wave infarction have more transient myocardial ischemia, whereas thrombolytic therapy seems to result in less residual ischemia. Exercise testing is more sensitive than ambulatory monitoring in the detection of postinfarction myocardial ischemia. There appears to be a poor association between transient myocardial ischemia and severe left ventricular dysfunction. Transient myocardial ischemia has been shown to provide prognostic information in different subsets of patients with previous myocardial infarction, but there is considerable disagreement about how this is expressed in terms of cardiac events. The precise role of postinfarction ST-segment monitoring in clinical practice has yet to be established.
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PMID:Transient myocardial ischemia after myocardial infarction. 772 94

There was a relationship of the degree of imbalance between thromboxane and prostacyclin, prostaglandins (PG) F2 alpha and E1 in patients with coronary heart disease concurrent with stable angina pectoris. A significant increase in the levels of thromboxane and PGF2 alpha was found with relative prostacyclin and PGE1 deficiency during graded exercise at the moment of transient myocardial ischemia; the imbalance significantly increased as exercise tolerance decreased. Transient myocardial ischemia induced by transesophageal left atrial pacing revealed unidirectional changes in plasma PG, as did exercise.
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PMID:[Thrombocytic-vascular hemostasis at rest and under physical loading in patients with ischemic heart disease]. 837 29


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