Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We obtained myocardial imaging with Tl during pharmacologic interventions. Dipyridamole-loading myocardial imaging was performed in 38 patients with CAD. The diagnostic accuracy of this method was 66%. The combination of dipyridamole-loading and exercise stress myocardial imaging increased the diagnostic sensitivity of CAD from 71% (exercise stress imaging only) to 87%. In addition, dipyridamole-loading myocardial imaging was useful for the diagnosis of CAD in patients who could not perform exercise stress test. Chest pain and ST-segment depression were induced less often during dipyridamole administration than exercise stress test. Animal experiments showed that dipyridamole caused abnormalities in myocardial blood flow and myocardial Tl uptake distal to the critical coronary stenosis. And dipyridamole increased myocardial blood flow by 142% and myocardial Tl concentration by 62% in the normally perfused myocardial segments. Ergonovine-loading myocardial imaging was performed in 8 patients with resting angina and without significant coronary stenosis. And in all of them, ergonovine induced cold-spots on myocardial imaging with or without chest pain and ST-segment shift. Ergonovine-loading myocardial imaging was useful for the diagnosis of angina induced by coronary artery spasm. The combination of initial and delayed resting myocardial imaging was useful to differentiate the underperfused but viable myocardium from the scar. And by comparing with radionuclide angiography obtained before and after NTG administration, NTG-loading myocardial imaging and ECG findings in 20 patients with CAD, we demonstrated that the transient defective myocardial segments were underperfused but viable.
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PMID:Noninvasive detection of coronary artery disease by myocardial imaging with thallium-201--the significance of pharmacologic interventions. 677 29

A series of 80 patients underwent continuous electrocardiography by Holter monitoring (ECG-H) for 24 hours to detect myocardial ischaemia. Fifty five patients were not on anti anginal therapy. The results of ECG-H were compared with those of exercise electrocardiography (ECG-E) (33 cases) and coronary angiography (50 cases). The ECG-H was positive in 31 of 43 patients (72%) with clinical (5 patients) or angiographic (38 patients) signs of ischaemic heart disease. The ECG-H was negative in 11 out of 12 patients (92%) with normal coronary; angiography. The sensitivity and specificity of ECG-H (57% and 92%) were inferior to those of ECG-E (75% and 100%) in the 33 untreated patients undergoing all three investigations. Twenty five recordings were compared with the ECG-E to assess anti anginal therapy. In asymptomatic patients ECG-H showed pathological ST depression in 10 cases, the ECG-E being positive in 1 7 cases. Anginal chest pain was induced on ECG-E in 5 out of 7 cases with a positive ECG-E and negative ECG-H. The lower sensitivity of the ECG-H compared to the ECG-E is related to several factors: 1) the sensitivity of the ECG-E increases with the number of exploratory electrodes; 2) reduced levels of physical activity decrease the sensitivity; in false negative cases the heart rate on ECG-H was only 74 +/- 7% of that corresponding to the threshold of positivity of the ECG-E, compared to 97 +/- 16% of the threshold heart rate in true positives (p less than 0,001); 3) the sensitivity of the ECG-H and ECG-E depends on the severity and distribution of the coronary lesions; false negative results were commoner in single vessel disease (57%) than in double or triple vessel disease (24%) (p less than 0,01). Anginal pain during the test increased the sensitivity to 92%. The specificity of the ECG-H is partially dependent on the recognition of positional variations of the ST segment. These were observed in 10% of cases but were generally easy to distinguish by their beat-to-beat appearances. The satisfactory specificity of the ECG-H in this study is also related to the high incidence of coronary artery disease in the population under study (80%). The predictive value of a positive test (Bayes theorem) was 97%, but that of a negative test was only 41%.
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PMID:[Value of continuous electrocardiographic recording using the Holter method in the diagnosis and surveillance of myocardial ischemia]. 678 40

Exercise tests were performed in 14 patients with untreated variant angina with frequent spontaneous attacks and in 15 patients after treatment abolished the attacks. (1) Anginal attacks associated with ST elevation were induced by exercise in 79% of untreated patients. By contrast, ST elevation was not observed in treated patients and ST depression was induced in 53% of the cases. (2) Exercise-induced ST elevation in untreated patients was shown in the same leads as the spontaneous attacks. (3) Exercise-induced ST elevation appeared initially during the recovery phase after exercise in 36% of untreated patients. Exercise-induced ST depression appeared during or immediately after exercise. (4) The reproducibility of exercise-induced ST elevation was low with repeated tests at different stages, but exercise-induced ST depression was consistently observed. (5) The exercise-induced ST depression and lack of ST changes in treated patients were highly suggestive of the presence and absence of organic coronary artery disease, respectively. However, the exercise-induced ST elevation in untreated patients did not differentiate between the presence or absence of organic stenosis of the coronary arteries. The results of exercise tests vary with the stage of variant angina. It is suggested that a coronary arterial spasm is a trigger mechanism for exercise-induced angina in cases of variant angina with frequent spontaneous attacks.
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PMID:Exercise test in variant form of angina pectoris. Comparison of the results with spontaneous attacks. 685 52

A patient had accelerated attacks of chest pain associated with transient ST elevation or depression in the anterior leads. Coronary angiogram revealed severe multi-vessel disease. Anginal attacks with conspicuous ST depression were induced repeatedly by both oral and sublingual administration of nifedipine. Among various vasodilator drugs tested on this patient, dipyridamole and hydralazine induced anginal attacks. These observations suggest that anginal attacks induced by administration of nifedipine may be related to the augmentation of myocardial oxygen consumption due to increases in cardiac output and heart rate, the coronary steal phenomenon, or an increase in venous return accompanied by the subendocardial underperfusion.
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PMID:Adverse response to nifedipine in unstable angina pectoris. 707 90

This study was undertaken to assess the conditions necessary to cause the "coronary steal" phenomenon in human subjects. We studied 42 patients (36 males, 6 females, ages 27--70 years) with known or suspected coronary artery diseases using continuous monitoring of the changes in blood pressure and electrocardiogram, thallium-201 myocardial imaging and selective coronary arteriography. Dipyridamole in a dose of 0.4 mg/Kg was given as an intravenous infusion for 4 min and thallium-201 was injected at the 4th minute after completion of the dipyridamole infusion. None of the 20 patients without significant coronary artery disease complained of anginal chest pain or showed ischemic S-T segment depression. Dipyridamole images showed no perfusion abnormalities in 17 of the 20 patients. On the other hand, in 4 of the 22 patients with significant coronary artery disease, anginal chest pain accompanied with S-T segment depression occurred after the dipyridamole infusion. Dipyridamole images showed perfusion abnormalities in 18 of the 22 patients. The 4 patients who experienced an anginal attack had 3 vessel disease on the coronary arteriogram and showed regional perfusion defects on scintigrams corresponding to the regions receiving collaterals. Before the onset of pain, the double product (heart rate X systolic arterial pressure) was unchanged significantly but there was a reduction in the systemic blood pressure. The overall data exhibit the following conditions under which attacks of angina pectoris are induced by dipyridamole: 1) the presence of multiple vessel disease, 2) a fall in systemic blood pressure, and 3) regional malperfusion caused by dipyridamole.
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PMID:Conditions for "coronary steal" caused by coronary vasodilator in man. 708 95

The effects of coformycin, a highly potent and specific inhibitor of the intracellular enzyme adenosine deaminase and the influence of dipyridamole, an inhibitor of the cellular adenosine uptake mechanism, were studied on the adenosine-induced changes in the electrical and mechanical activity of isolated electrically driven left atria of guinea-pig hearts. Adenosine (0.1 mumol/l-1 mmol/l) by itself elicited a concentration-dependent decrease in the action potential duration and contractile force of atrial preparations. Coformycin, when applied in a concentration inducing a nearly complete inhibition of adenosine deaminase activity in intact atrial myocardium (7 mumol/l), enhanced the adenosine-induced reduction both in the duration of the intracellularly recorded action potential and in the contractile force of the atria, preferentially at higher concentrations of adenosine (10 mumol/l-1 mmol/l). The calculated half recovery time during wash-out (t1/2) was found to be about 6 times longer than that of controls (317.5 +/- 47 and 51.3 +/- 4.3 sec, respectively). In contrast with adenosine, the action of 2-chloroadenosine (an adenosine deaminase resistant purine derivative) on the atrial contractile force was not affected in the presence of coformycin. Dipyridamole (0.3 mumol/l) was capable of significantly potentiating the adenosine-induced depression of atrial mechanical activity, mainly at lower concentrations of adenosine (0.1-10 mumol/l). Preincubation of atrial preparations with a combination of coformycin and dipyridamole produced a strong enhancement in the adenosine-induced decrease of mechanical activity at all concentrations of adenosine. It is suggested that adenosine might exert its myocardial actions not only through the known extracellular, but also via possible intracellular purinoceptors.
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PMID:Potentiation of the myocardial actions of adenosine in the presence of coformycin, a specific inhibitor of adenosine deaminase. 710 13

1 The effects of Ca2+ -antagonists on the relationships between alternate changes in the ST-T complex in the epicardial electrogram, ST-T alternans, and associated excitation-conduction abnormalities during coronary occlusion were examined in anaesthetized dogs. 2 Epicardial unipolar electrograms, bipolar electrograms (BPEG) and monophasic action potentials (MAP) were recorded with unipolar, composite and suction electrodes, respectively. 3 ST-T alternans was associated with serious conduction delay. During the period of ST-T alternans, the amplitude of MAP changed alternately and the negative deflection of the ST-T complex was associated with a larger MAP. A depression of the TQ level and decrease in the resting potential of MAP were marked. 4 Verapamil (0.2 mg/kg) and diltiazem (0.5 mg/kg) inhibited ST-T alternans, conduction abnormalities, TQ depression and changes in MAP. However, after these drugs, the TQ depression and the decrease in the resting potential were evident after a longer period of occlusion at a time when ST-T alternans, conduction abnormalities and alternate changes in MAP were still inhibited. Dipyridamole (0.5 mg/kg) had no effect on either ST-T alternans or the conduction abnormalities. 5 Verapamil and diltiazem inhibited ST-T alternans and the associated excitation and conduction abnormalities. The effects of these two drugs cannot be explained on the basis of attenuation of the decrease in the resting potential.
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PMID:Effects of calcium antagonists on the alternation of the ST-T complex and associated conduction abnormalities during coronary occlusion in dogs. 731 86

Noninvasive evaluation of coronary artery disease is difficult in elderly patients because of their limited exercise-capacity. The diagnostic and prognostic value of dipyridamole perfusion scintigraphy was assessed in 147 patients aged 65 years and older. All patients underwent coronary angiography. Initially, 32 patients had percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG). The other 115 patients were first treated medically and followed for a mean of 29 +/- 22 months. Nine patients (7.9%) had cardiac events including cardiac death and coronary intervention (PTCA or CABG) during the follow-up. Dipyridamole perfusion scintigraphy was performed safely in all patients, whereas treadmill exercise testing could not be adequately performed in 24 patients, 18 of whom had multivessel disease. Multiple regression analysis showed that: fixed defect and reversible defect were powerful detectors of coronary lesions (p = 0.0001, p = 0.0027, respectively), all patients with fixed disease and 94% of patients with only reversible defect had significant coronary lesion; Diffuse slow washout and ST depression were statistically significant for detecting multivessel coronary lesions in patients with fixed disease (p = 0.0001, p = 0.017, respectively), the sensitivity and specificity of diffuse slow washout and/or ST depression for detecting multivessel coronary lesions ware 85% and 74%, respectively, and ST depression was statistically significant for detecting multivessel coronary lesions (p = 0.0002) in patients with only reversible defect, the sensitivity and specificity of ST depression were 88% and 64%, respectively. Cox survival analysis identified diffuse slow washout as the best predictor of future cardiac events among the scintigraphic variables.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Diagnosis and prognosis of elderly patients with coronary artery disease: assessment with dipyridamole thallium imaging]. 750 Feb 64

Dipyridamole thallium-201 imaging, using single-photon emission computed tomography, was evaluated for its safety and diagnostic efficacy in 109 patients with angiographically documented coronary artery disease and 35 normal subjects. The most common side effects after the intravenous administration of dipyridamole thallium-201 (0.56 mg/kg) included chest pain in 41 patients, dizziness in 20 patients, headache in 16 patients, and ST segment depression > or = 1 mm in 15 patients. Aminophylline was required to reverse the side-effects in 46 patients, and 45 of the 46 patients experienced complete relief of symptoms. Of the 109 patients with coronary artery disease, 104 had abnormal dipyridamole thallium images. The per patient sensitivity was 95%. Of the 35 normal subjects, 27 had normal thallium images. The per patient specificity was 77%. The sensitivity and specificity for the individual vessels were 84% and 87% for the left anterior descending artery, 67% and 97% for the left circumflex artery, and 89% and 85% for the right coronary artery, respectively. Dipyridamole thallium-201 imaging is a relatively safe noninvasive method and is an effective alternative to exercise thallium-201 scintigraphy for the diagnosis of coronary artery disease.
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PMID:Diagnosis of coronary artery disease using dipyridamole thallium-201 imaging. 763 92

The recognition of coexistent coronary artery disease (CAD) in patients with hypertrophic cardiomyopathy may be difficult by noninvasive testing based upon electrocardiographic changes or perfusion defects. Dipyridamole-stress echocardiography has proved a sensitive and highly specific test for noninvasive diagnosis of CAD in various patient subsets. To establish the feasibility, safety, and diagnostic accuracy of dipyridamole-stress echocardiography in patients with hypertrophic cardiomyopathy, we performed high-dose dipyridamole testing (up to 0.84 mg/kg over 10 minutes) in 88 patients with hypertrophic cardiomyopathy (63 men; mean age +/- SD, 46 +/- 17 years). A subset of 60 patients was referred for coronary angiography independently of test results; CAD was defined as > or = 50% diameter narrowing in at least 1 major coronary vessel. Dipyridamole echocardiography/electrocardiography testing was completed in all patients, with no limiting side effects or adverse reactions. In the subgroup of 60 patients with coronary angiography (14 with and 46 without CAD), chest pain occurred in 18 patients (8 with and 10 without CAD, p = NS); ST-segment depression > or = 2 mm from baseline in 28 (7 with and 21 without CAD, p = NS); and transient dyssynergy in 10 patients (10 with and none without CAD, p < 0.0001). Assuming the transient regional dyssynergy to be the only criterion of positivity, the dipyridamole echocardiography test showed 71% sensitivity, 100% specificity, 100% positive predictive value, and 93% diagnostic accuracy for diagnosis of angiographically assessed CAD. We conclude that high-dose dipyridamole echocardiography testing may be considered a feasible and accurate tool for the noninvasive diagnosis of CAD in patients with hypertrophic cardiomyopathy.
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PMID:Dipyridamole echocardiography for diagnosis of coexistent coronary artery disease in hypertrophic cardiomyopathy. Echo-Persantine International Cooperative (EPIC) Study Group--Subproject Hypertrophic Cardiomyopathy. 771 85


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