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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intracoronary administration of contrast agents may be associated with contractile dysfunction and arrhythmias. To further establish the mechanisms of these alterations, we studied high-energy phosphate metabolism, developed pressure, the occurrence of arrhythmias, and the effects of verapamil during infusion of ionic and nonionic agents in isovolumic, retrogradely perfused rat hearts using 31P nuclear magnetic resonance imaging (NMR). Diatrizoate meglumine (Renografin) infusion reduced developed pressure (DP) to 17.1 +/- 3.4% (p less than 0.001) of the control level, and immediately following termination of the infusion, sudden ventricular tachycardia (VT) was observed in four of six hearts. In the presence of verapamil, meglumine reduced DP to 13 +/- 1.9% of control values and none of these six hearts developed VT. Iopamidol infusion in the presence of verapamil (n = 6) and alone (n = 6) resulted in a decrease in DP to 87% of control value, and no arrhythmias, significant change in high-energy phosphate levels, or changes in pH were observed. These results suggest that contrast-induced contractile depression is not mediated by changes in high-energy phosphate metabolism or pH. Arrhythmias associated with meglumine administration alone and suppressed by verapamil are probably related to calcium loading.
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PMID:Contractile, metabolic and arrhythmogenic effects of ionic and nonionic contrast agents in the isolated rat heart. 151 93

Cardiac tolerance to intravenous digital subtraction angiography (ANVV) was evaluated by a prospective study in a continuous series of patients of both sexes investigated for various arterial diseases and classified initially into "cardiac" and "non-cardiac" cases. Ischemic and rhythmic electrocardiographic modifications were monitored, the contrast medium (PC) used being randomly selected between Ioxaglate and Iopamidol. Of the first 46 patients studied, 40% had had more than one auricular and/or ventricular extrasystole (ES), 18% had painless depression of the ST segment (greater than or equal to 0.5 mm) and 46.7% both effects. In the 17 "cardiac" patients, depression of ST and the ES were more frequent (p less than 0.02 and p less than 0.05 respectively) than in the 29 "non-cardiac" cases. There was absence of difference between Ioxaglate and Iopamidol with respect to frequency of disorders of repolarization, but Ioxaglate appeared to provoke more ES than Iopamidol (respectively 13 of 23 and 5 of 22 cases, p = 0.02). Major cardiac complications were not reported, and it is concluded, after discussion of cardiovascular effects of PC injection, that intravenous digital subtraction angiography is generally well tolerated but requires some precautions in patients with cardiac affections.
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PMID:[Evaluation of cardiac tolerance of intravenous digital angiography]. 329 96

Metrizamide was the first water-soluble contrast medium with a neurotoxicity low enough to allow it to be used routinely in the entire subarachnoid space. However, neurologic complications are still observed in some patients following the use of metrizamide. The cause of this toxicity has not been established, but existing evidence suggests an interference with glucose metabolism. In previous studies, a depression in CO2 production in neural tissue slices was demonstrated when isotonic metrizamide was added but not isotonic iohexol. In addition to iohexol, there is another new, nonionic, monomeric, water-soluble CM, iopamidol, soon to be released for clinical use in the United States. Iopamidol, like iohexol, has shown fewer adverse reactions and seems to be safer for myelography than metrizamide. Direct comparative studies of iopamidol and iohexol are sparse and the cause of their toxicity is not yet understood. This study was performed to determine the effect of iopamidol on neural tissue glucose metabolism as compared with the effects of iohexol and metrizamide. Metrizamide decreased CO2 production in neural tissue slices by 23%. Iopamidol and iohexol did not produce significant depression. Moreover, this model could not demonstrate any significant difference between iopamidol and iohexol in direct comparisons. The new monomeric contrast media, iopamidol and iohexol, thus do not appear to interfere with glucose metabolism. Adverse reactions to these new media are most likely caused by other mechanisms.
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PMID:Iopamidol and neural tissue metabolism. A comparative in vitro study. 377 Nov 51

The chemistry of low-osmolality contrast agents is reviewed, the effects of these agents on vascular and organ physiology are compared with the effects of conventional ionic contrast media, and guidelines for intravascular use of the low-osmolality agents in selected high-risk patients are presented. Three low-osmolality contrast agents, the nonionic media iohexol (Omnipaque, Winthrop-Breon) and iopamidol (Isovue, Squibb) and the dimeric medium ioxaglate meglumine-sodium (Hexabrix, Mallinckrodt) have recently been introduced into the contrast-media market. Compared with conventional ionic contrast media, these new agents demonstrate approximately one third of the osmolality per given iodine concentration (degree of roentgenographic opacification). Therefore, the risks of hyperosmolarity-induced reactions to contrast media are lower with the new agents. The low-osmolality agents may be associated with a reduced incidence of contrast-media-induced hypersensitivity reactions. Because of their lower osmolality, these agents produce less vessel dilation, vascular endothelial damage, and associated pain and discomfort than equi-iodine concentrations of the conventional ionic media. They also demonstrate a reduction in the incidence and severity of contrast-media-induced renal vasoconstriction and proteinuria, hemodynamic alterations, negative chronotropic effects, depression of myocardial contractility, and neurotoxicity in the presence of an altered blood-brain barrier. These low-osmolality agents produce fewer undesirable physiological effects than conventional contrast agents, but the cost of the new products can be more than 10 times as great. Therefore, the new products should be used selectively in patients known to be at increased risk for reactions to intravascular contrast media. A scoring system was developed to permit rapid recognition of documented single or multiple risk factors and subsequent determination of whether to administer a low-osmolality agent.
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PMID:Evaluation of intravascular low-osmolality contrast agents. 378 Jan 59

The cardiovascular response produced during pulmonary angiography performed with the standard ionic agent diatrizoate (Renografin 76) and a new non-ionic agent iopamidol was compared. Nine dogs were evaluated while ventilated on room air and on 10% O2 which significantly elevated pulmonary arterial pressure. Iopamidol produced similar changes in mean aortic and pulmonary arterial pressures compared with normal saline (less than 20% change). Renografin 76, however, produced a significantly greater elevation in mean pulmonary arterial pressure (a 41% increase) and depression in mean aortic pressure (a 40% reduction) than either saline or iopamidol (p less than 0.01). These results were similar for dogs being ventilated with room air and oxygen. The results indicate that iopamidol should be better tolerated and therefore a safer contrast agent for pulmonary angiography than diatrizoate.
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PMID:Pulmonary angiography with iopamidol and Renografin 76 in normal and pulmonary hypertensive dogs. 666 67

The aim of this study was to investigate the mechanisms of the cardiodepressive action of ionic and non-ionic contrast media currently used in coronary arteriography. Experiments carried out on isolated preparations of cat papillary muscle, treated with increasing concentrations of Telebrix 39, Radioselectan, Hexabrix and Iopamidol 370 and 300, on the one hand and, on the other hand, a pre-determined dose of Telebrix and Iopamidol 300 during hypoxia and subsequent reoxygenation, showed that, at constant Ca2+ concentrations: (1) The cardiodepressive effects of contrast media are correlated with the hyperosmolality that they induce. When osmolality was higher than 400 mOsm, all the products caused a reduction of the peak force (PF: 40.49 +/- 5.15%), the maximum velocity of contraction (Vmax: 39.85 +/- 3.66%) and of the peak velocity of relaxation (Vrelax: 23.30 +/- 2.20%) (P less than 0.01). The time to peak force (TPF), on the other hand, remained constant, whereas the half-relaxation time (THR) was increased. No significant differences were observed between these effects and those induced by control iso-osmolar solutions when the same osmolality was induced. In practice, however, the critical hyperosmolality value of 400 mOsm is never reached when using non-ionic contrast media such as Hexabrix and Iopamidol 300. This could explain the excellent tolerance to these substances. (2) During hypoxia and reoxygenation, the effect of hyperosmolality is more marked. Thus, the non-ionic contrast medium, Iopamidol 300 (340 mOsm), reduces the hypoxic contractility depression (PF: 53.10 +/- 2.60% compared to the control values of 47.60 +/- 5.00%, P less than 0.01), whereas, at the same dose, the ionic medium Telebrix is hyperosmolar (440 mOsm) and induces a more pronounced hypoxic depression of contractility (P less than 0.01). The critical hyperosmolality is never reached during ventriculography (320 mOsm), whatever the medium used, but it can be observed during coronary arteriography. It is, therefore, important to use non-ionic contrast media in the investigation of unstable angina and of acute myocardium infarction.
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PMID:Effects of contrast media used in angiocardiography on the mechanical performance and the relaxation of normal and ischaemic myocardium. 672 85