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)

Patients with coronary artery disease (CAD) frequently have left ventricular (LV) wall motion abnormalities in the absence of symptoms. Thirty-one patients with such LV wall motion abnormalities in the absence of symptoms participated in a study of the response of these abnormalities to ascending doses of intravenous nitroglycerin (NTG). In a subgroup of 20 patients the relation between the location of LV wall motion abnormalities and the presence or absence of significant CAD (greater than or equal to 50% diameter reduction), in the vessel supplying the LV region, was assessed. Wall motion improved after intravenous NTG; the ejection fraction increased by 3.7% (mean p less than 0.05) and by 9.4% in the 19 patients who responded. There was no significant increase in heart rate; both LV systolic and end-diastolic pressures decreased minimally (12.5 and 3.5 mm Hg, respectively, p less than 0.05). The ejection fraction response was observed with NTG doses less than or equal to 200 micrograms and no dose-response relation was apparent. In the subgroup subjected to regional wall motion analysis, the presence of dyskinesia was significantly (p = 0.007) associated with the presence of important CAD in a vessel supplying that region. Further, the fact that wall motion improvement after NTG was significantly (p = 0.002) associated supports the concept that silent ischemia results in LV regional wall motion abnormalities, which can be reversed with low dose intravenous NTG.
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PMID:Left ventricular dyskinesia reversed by intravenous nitroglycerin: a manifestation of silent myocardial ischemia. 309 12

Timing of coronary artery bypass grafting after acute myocardial infarction (MI) is controversial, especially if myocardial function is depressed. Early coronary artery bypass grafting may result in reperfusion injury causing cardiac failure. Delay, however, may risk a second ischemic event. This study was performed to determine if four preoperative factors--time after MI, ejection fraction, ischemia (need for intravenous administration of nitroglycerin), and failure (need for inotropic support)--independently predict postoperative cardiac failure. Postoperative failure was defined as the need for inotropic support or intraaortic balloon pumping. The study group consisted of 145 patients who underwent isolated coronary artery bypass grafting between January, 1980, and July, 1985, within 4 weeks of an acute MI. Postoperatively 38 patients (26%) had cardiac failure. Five patients, all of whom had postoperative cardiac failure, died. Univariate and stepwise logistic regression analyses showed preoperative failure (p = .0001), ejection fraction less than 45% (p = .002), and preoperative ischemia (p = .02) were predictors of postoperative cardiac failure. Time after MI was not found to be an independent predictor (p = .96). We conclude that if ischemia or threatening coronary anatomy is present early after MI and clinical improvement is not occurring, operative intervention should be strongly considered at that time, as it does not appear that delay itself reduces the risk of cardiac failure and may risk a second ischemic event.
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PMID:Determinants of cardiac failure after coronary bypass surgery within 30 days of acute myocardial infarction. 309 99

The treatment of 15 patients with coronary heart disease and exertion-related angina pectoris with isosorbide dinitrate (ISDN) tablets in 4 doses (6 X 5 mg, 6 X 20 mg, 6 X 40 mg, 6 X 80 mg) in a randomized sequence for 1 week each resulted in a dose-related improvement of ischemia (ST-segment depression during stress testing) as compared to placebo: 5 mg (30 mg/day): 24% (p less than 0.05); 20 mg (120 mg/day): 40% (p less than 0.05); 40 mg (240 mg/day): 60% (p less than 0.01); 80 mg (480 mg/day): 74% (p less than 0.01). Continuation of treatment for another 4 weeks with 480 mg/day led to a slight decrease in antianginal activity, with a 55% improvement of ST-depression. The frequency of angina pectoris was also lowered in a dose-related manner. For nitroglycerin in oral sustained release form (matrix system) a dose-related antianginal efficacy could be demonstrated in 12 patients enrolled in a double-blind cross-over trial: 2.6 mg (single dose): 23% (n.s.); 6.5 mg: 38% (p less than 0.01); 10 mg: 55% (p less than 0.001); 20 mg: 74% (p less than 0.0001). The duration of action of 20 mg was 4 hours. Transdermal nitroglycerin also proved to be effective in a dose related fashion. In 12 patients undergoing 1-week treatment periods with 5 cm2, 10 cm2 and 20 cm2-patches ST-depression was favourably influenced by 15% (n.s.), 22% (p less than 0.05) and 46% (p less than 0.001) 3 hours after administration. No antiischemic efficacy was demonstrable 24 hours after medication.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Dose-response relationship of nitrate therapy of angina pectoris]. 309 86

In 14 patients during exercise, intravenous nitroglycerin improved anginal threshold and increased workload compared with control subjects. At similar workloads, the decreased left ventricular volumes suggested decreased myocardial oxygen consumption due to peripheral unloading. At maximal exercise with nitroglycerin (50 +/- 17 to 79 +/- 15 watts), rate-pressure product and end-diastolic volumes were higher with less ischemia, suggesting myocardial supply was improved by nitroglycerin.
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PMID:Antianginal effects of nitroglycerin during exercise-induced angina: hemodynamic and left ventricular function changes related to indexes of myocardial oxygen consumption. 312 May 60

Recent evidence suggests that traditional approaches to the use of nitroglycerin (NTG) in patients with chronic stable angina should be reconsidered. Studies of the time to onset of hemodynamic effects of sublingual NTG suggest that the first detectable effect, on left ventricular end-diastolic pressure, occurs at a mean of 90 seconds after administration. By timing the duration of exertional angina after formal exercise testing, one can show that, on average, chest pain is gone within 2 minutes. Thus, in many patients, it is unlikely that sublingual NTG can further shorten episodes of exertional angina. The value of sublingual NTG is greater when patients exercise beyond the onset of pain, when patients have more protracted episodes of exertional pain and when there is a need to resume immediately the activity that brought on the angina. With respect to angina prophylaxis, the pioneering studies of Parker and co-workers have now been amply confirmed. Continuous nitrate administration by oral, transdermal or intravenous routes results in substantial, albeit incomplete, tolerance. Tolerance occurs even when high plasma concentrations are achieved and persist over time. Tolerance can eliminate responsiveness to sublingual NTG. Preliminary evidence suggests that tolerance to the antianginal effects of NTG at maximal exercise may be more marked than tolerance to the effects of NTG on silent ischemia at submaximal activity levels. The significance of this dissociation in time course and its implications are unclear at this time. Three potential strategies exist for avoiding NTG tolerance in patients with chronic stable angina. Administration of a thiol donor has been shown to reverse some hemodynamic manifestations of tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nitroglycerin in chronic stable angina pectoris. 312 May 61

Fifteen patients aged 55 +/- 6 years (mean +/- SD) with mild, chronic stable angina were evaluated after 2 weeks of sublingual nitroglycerin therapy (control) and also after 12 weeks of treatment with either propranolol, up to 320 mg per day, or nifedipine, up to 120 mg per day, in order to measure signs of ischemia and the response of symptoms to therapy. Compared with the control period, there was a decrease in average daily episodes of angina from 1.0 +/- 0.8 to 0.5 +/- 0.4 with treatment (p = 0.10). There was a significant decrease of greater than or equal to 1.0 mm ST segment depression (both symptomatic and asymptomatic), from 6.1 +/- 6.5 to 1.5 +/- 2.4 episodes per 24 hours, p less than 0.001, and of asymptomatic episodes of ST segment depression, from 3.5 +/- 3.9 to 1.0 +/- 2.1 episodes per 24 hours, p = 0.03. The number of patients who had any episodes of greater than or equal to 1.0 mm ST segment depression on their 24-hour ECG decreased from 14 to 6 (93% to 40% of patients, p = 0.005) with treatment, and the number of patients with any episodes of ST segment depression without symptoms decreased from 11 to 5 (73% to 33% of patients, p = 0.07). There was an insignificant increase in treadmill time from 333 +/- 134 to 380 +/- 156 seconds, and an insignificant decrease in maximum double-product from 16,631 +/- 3,599 to 14,922 +/- 4,086; the number of patients with angina at maximum exercise decreased from 13 to 10 (87% to 67%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of pharmacologic therapy on angina frequency, ST segment depression during ambulatory ECG monitoring, and treadmill performance in patients with chronic stable mild angina. 312 46

The pathophysiological significance of coronary collateral vessels remains controversial, despite previous intensive studies. We performed the multistage supine ergometer stress test for 26 patients with effort angina and collaterals. The changes in the collaterals were observed during each anginal attack by coronary angiography before and after intravenous nitroglycerin. The collaterals of 21 patients disappeared or diminished during exercise-induced angina before nitroglycerin administration, and were unchanged in the remaining five cases. However, the collaterals of all patients after nitroglycerin administration were unchanged or increased during exercise-induced angina. Considering there were no significant changes in pulmonary arterial end-diastolic pressures during angina before and after nitroglycerin administration, a pressure gradient between the donor and recipient coronary arteries was suggested as being related to the patency of the collaterals. These results suggested the following: 1. It is not appropriate to postulate that the collaterals visualized at rest may remain unchanged during exercise-induced angina. 2. It is not reasonable to conclude that exercise accelerates the development of collateral circulation. 3. One favorable effect of nitroglycerin administration is the prevention of exercise-induced ischemia via collateral circulation.
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PMID:[Collateral circulation during exercise-induced angina: evaluation by coronary angiography]. 312 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

Because silent ischemia is not associated with an increase in heart rate and, being asymptomatic, its treatment requires constant therapeutic plasma levels of the drug used, a transdermal nitroglycerin patch (Deponit) was selected for treatment of this condition. Eight patients with documented silent ischemia were studied. All patients also had angina on effort treated with calcium antagonists (n = 8) and beta blockers (n = 6). They were evaluated by 24-hour ambulatory electrocardiographic monitoring. The transdermal nitroglycerin patch, 20 to 30 mg/24 hours, reduced the number of silent ischemic episodes from 9.25 +/- 5.52 to 2.4 +/- 2.0 episodes per 24 hours (p less than 0.001). The maximal ST-segment depression was reduced from 3.1 +/- 0.7 to 0.9 +/- 0.7 mm (p less than 0.001). Ventricular premature beats were significantly reduced, by 50%. Symptomatic ischemic episodes were completely suppressed. Thus, transdermal nitroglycerin, in moderate doses, is effective in suppressing silent ischemia in patients with angina pectoris who have silent ischemic episodes despite treatment with other antianginal agents.
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PMID:Transdermal nitroglycerin patches for silent myocardial ischemia during antianginal treatment. 312 33

We performed percutaneous transluminal coronary angioplasty as an emergency procedure in 60 patients with unstable angina pectoris that was refractory to treatment with maximally tolerated doses of beta-blockers, calcium antagonists, and intravenous nitroglycerin. The initial success rate for angioplasty was 93 per cent (56 patients). There were no deaths related to the procedure, although total occlusion occurred in four patients. Despite emergency bypass grafting, all four sustained a myocardial infarction. All the patients were followed for at least six months. Late cardiac death occurred in one patient, whereas eight had recurrent angina pectoris. There was no progression to myocardial infarction. The restenosis rate was 28 per cent (13 of 46) in the patients with initially successful coronary angioplasty who had repeat angiography. Improved cardiac functional status after sustained successful coronary angioplasty was demonstrated by an almost normal capacity on bicycle exercise testing and the absence of ischemia during thallium isotope studies in 80 per cent. We conclude that emergency percutaneous transluminal coronary angioplasty may be useful for the treatment of selected patients with unstable angina pectoris who are unresponsive to intensive pharmacologic treatment.
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PMID:Emergency coronary angioplasty in refractory unstable angina. 315 64


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