Real-time compared to off-line evaluation of segmental wall motion abnormalities with transesophageal echocardiography using dobutamine stress testing.
ABSTRACT To compare real-time (on-line) monitoring of myocardial ischemia with transesophageal echocardiography (TEE) with off-line reviewing during a dobutamine stress test in patients undergoing coronary artery bypass grafting (CABG).
Prospective observational study.
Tertiary care university hospital.
Seventeen patients undergoing CABG.
TEE and electrocardiographic monitoring of myocardial ischemia during dobutamine stress testing.
Sixteen of 17 patients developed myocardial ischemia as diagnosed by TEE or electrocardiographic monitoring. On-line and off-line TEE detected myocardial ischemia in 11/17 and 12/17 patients, respectively. In total, 532 myocardial segments were analyzed at baseline and at peak dobutamine dose. The concordance between on-line and off-line assessments of segmental wall motion was poor at baseline and at peak dobutamine dose (κ = 0.28 and 0.29, respectively). The concordance for detecting myocardial ischemia (worsening in regional wall motion by ≥1 class or a biphasic response in any segment) was better between on-line and off-line analysis (κ = 0.60). There was no agreement between ST-segment monitoring and on-line TEE (κ = -0.27) and between 12-lead electrocardiogram and on-line TEE (-0.11). There was no agreement between ST-segment monitoring and off-line TEE (κ = -0.15) and between 12-lead electrocardiogram and off-line TEE (κ = -0.27).
Only a fair agreement exists between on-line and off-line analysis of myocardial ischemia during dobutamine stress testing in patients undergoing CABG. However, TEE misses up to one third of ischemic episodes and the present observations suggest using continuous electrocardiographic methods to complement TEE monitoring.
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ABSTRACT: The role of gibberellin (GA) and ethylene in submergence-induced petiole elongation was studied in two species of the genus Rumex. Analysis of endogenous GAs in the flooding-tolerant Rumex palustris Sm. and the intolerant Rumex acetosa L. by gas chromatography-mass spectrometry showed for both species the presence of GA1, GA4, GA9, GA19, GA20 and GA53. Gas chromatography-mass spectrometry analysis of R. palustris petiole tissue of submerged plants showed an increase in levels of 13-OH GAs, especially GA1, compared with drained plants. This effect could be mimicked by application of 5 μL L−1 ethylene. In R. acetosa, no differences between levels of GAs in drained or submerged plants were found. In R. palustris, both submergence and ethylene treatment sensitized petioles to exogenous gibberellic acid (GA3). In R. acetosa the effect was opposite, i.e. submergence and ethylene de-sensitized petioles to GA3. Our results demonstrate the dual effect of ethylene in the submergence response related to flooding tolerance, i.e. in the flooding-tolerant R. palustris ethylene causes an increased concentration of and sensitivity to GA with respect to petiole elongation while in the intolerant R. acetosa ethylene reduces growth independent of GAs.Planta 07/1997; 203(1):20-25. · 3.38 Impact Factor
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ABSTRACT: Ethylene plays a key role in the rapid elongation of deepwater rice. We cloned cDNAs corresponding to at least three members of the 1-aminocyclopropane-1-carboxylate (ACC) synthase gene family of deepwater rice (Oryza sativa ev. Plai Ngam). Genomic DNA gel blot analysis confirmed the presence of a multigene family. Expression patterns were studied by Northern blot on poly(A+) RNA prepared from plants exposed to abscisic acid, ACC, gibberellic acid (GA), indole-3-acetic acid, jasmonic acid, submergence and wounding. The mRNA levels were suppressed by ACC, GA, submergence and wounding, but remained relatively constant under all other conditions.Plant Science - PLANT SCI. 01/1997; 124(1):79-87.
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ABSTRACT: Adverse effects of elongation growth on tolerance to complete submergence for up to 14 d were evaluated in rice seedlings of cultivars which differed in submergence tolerance. There is a good negative correlation between per cent survival and elongation growth of genotypes during complete submergence ( r = − 0.81). When elongation growth underwater is minimized by application of a gibberellin biosynthesis inhibitor, per cent survival increases by as much as 50 times for one cultivar. These effects are likely related to elongation growth since (i) addition of gibberellin had the opposite effect by reducing survival, and (ii) when the elongation inhibitor and gibberellin were added together, there was no effect on elongation growth and the per cent survival did not change. A GA-deficient mutant of rice which had little elongation ability during submergence showed a high level of submergence tolerance when plants were submerged at equal initial dry weights and carbohydrate levels relative to a submergence-tolerant cultivar. These results are consistent with the hypothesis that elongation growth competes with maintenance processes for energy and hence reduces survival during submergence. The impact of these findings is that in environments where elongation ability is not required, there is a potential to increase submergence tolerance of agriculturally important cultivars by selecting for least elongation, at least during periods of complete submergence. Furthermore, this trade-off between stimulated elongation growth and submergence tolerance will have important ecological consequences for the distribution of plant species in different flood-prone environments.01/1996;