Biomedical subjects

Y Hirano

Publications and source records attributed to Y Hirano.

At least 37 records · Page 2Linked to original sources

PubMed2002

[Off-pump Cx grafting for unstable angina with left main trunk lesion].

Recently, off-pump coronary artery bypass grafting (OPCAB) has been rediscovered and spread to avoid the deleterious effect of cardiopulmonary bypass. In OPCAB, surgical exposure of Cx grafting site often threats the hemodynamic stability. We retrospectively analysed the 13 patients with acute coronary syndrome due to LMT lesion who underwent emergent OPCAB to accomplish the safe Cx grafting. We assessed the intraoperative hemodynamic changes and early results of OPCAB through the use of new devices and techniques. Myocardial tissue oxygen saturation was measured by near-infra red spectroscopy during OPCAB. All procedures were completed without hemodynamic deterioration and conversion to cardiopulmonary bypass. No hospital deaths or complications were noted. The early patency rate was 100 percent and perioperative maximal CK-MB was 16.6 +/- 4.7 IU/l. Concomitant use of ischemic preconditioning and KATP opener, oxidative radical scavenger, PD III inhibitor, ameliorated ischemic cardiac dysfunction during occlusion of the coronary artery and improved the postischemic functional recovery. These results suggest that intra-operative compound management may decrease the risk of Cx grafting of OPCAB.

Aged↗

PubMed2002

[Off-pump coronary artery bypass grafting for unstable angina pectoris combined with hypothyroidism and chronic renal failure; report of a case].

Coronary artery bypass grafting for patients with ischemic heart disease and hypothyroidism contains many controversies, and chronic renal failure causes perioperative water-electrolyte balance disorders. We experienced a case of unstable angina pectoris combined with hypothyroidism and chronic renal failure successfully treated by off-pump coronary artery bypass grafting (OPCAB). A 68-year-old man with a history of hypothyroidism and chronic renal failure was hospitalized with chest pain. Cardiac catheterisation revealed a 90% stenosis of segment 3, 11 and right ventricular (RV) branch, 75% stenosis of segment 6 and 50% stenosis of segment 5. His thyroid function was normal with orally administered levothyroxine. OPCAB was performed safely with hemodialysis until a day before operation and hemofiltration from a day after operation, and postoperative course was uneventful.

Aged↗

PubMed2001

Bile acids regulate RANTES gene expression through its cognate NF-kappaB binding sites.

Regulated upon activation, normal T-cells expressed and secreted (RANTES) mainly migrates memory type CD4+ T-lymphocytes to inflamed tissues. In this study, we examined effects of bile acids on RANTES gene expression in human hepatoma cells. Upon stimulation with hydrophobic bile acids, RANTES proteins were clearly increased. Semiquantitative RT-PCR analysis revealed that chenodeoxycholic acid (CDCA) induced RANTES mRNA expression. Moreover, RANTES was transcriptionally induced in two hepatoma cell lines by CDCA, presumably via its cognate NF-kappaB binding sites in the RANTES promoter. Electrophoretic mobility shift assay revealed that hydrophobic bile acids induced DNA-binding activity of NF-kappaB. Additionally, the magnitude of inducibility was closely associated with the hydrophobicity of bile acids. In conclusion, we might indicate that bile acids induced RANTES gene expression in human hepatoma cells, possibly suggesting that bile acids play an important role in migration of inflammatory cells by RANTES to the liver in patients with primary biliary cirrhosis.

Antibodies↗

PubMed2001

Direct demonstration of rapid degradation of nuclear sterol regulatory element-binding proteins by the ubiquitin-proteasome pathway.

Sterol regulatory element-binding proteins (SREBPs) are synthesized as membrane-bound precursors and processed to generate transcriptionally active forms. The active SREBPs translocate to the nucleus, induce the expression of responsive genes, and are degraded very rapidly. Treatment with proteasome inhibitors elevates the amount of the endogenous nuclear SREBPs, but not the precursors, in HeLa cells. Nuclear forms of human SREBP-1a (amino acids 1-487) and SREBP-2 (amino acids 1-481), which are transiently expressed in stable Chinese hamster ovary cell lines (CHO-487 and -481), are also stabilized by proteasome inhibitors, suggesting that the nuclear SREBPs are likely to be substrates for the proteasome-dependent proteolysis. The stabilized nuclear SREBPs actively induce the expression of responsive genes including hydroxymethylglutaryl (HMG)-CoA synthase, fatty acid synthase, and the low density lipoprotein receptor. The rapid turnover of nuclear SREBP-1a is not affected by the intracellular sterol levels, and the half-life is estimated to be approximately 3 h. The nuclear SREBPs are found conjugated with a polyubiquitin chain. When this conjugation is inhibited by overexpression of mutant ubiquitin that is defective in polyubiquitination, the nuclear SREBPs are partly stabilized and induce the expression of the responsive gene, suggesting that the ubiquitin-conjugated SREBPs are substrates for the proteasome. Taken together, these results demonstrate that the ubiquitin-proteasome system degrades SREBPs and that this system controls the expression of SREBP-responsive genes.

Animals↗

PubMed2001

Monooxygenation mechanism by cytochrome p-450.

The substrate oxygenation mechanism by an ultimate species in monooxygenation by cytochrome P-450 (compound I) was investigated by the density functional theory method. An initial model compound was constructed from a structure obtained by 300-ps molecular dynamics simulation of compound I-formed P-450cam under physiologic conditions, and it consisted of porphine for protoporphyrin IX, S(-)-CH(3) for the side chain of Cys357 of the fifth ligand of heme, a methane molecule for the substrate, a heme iron, and an oxygen atom of the sixth ligand of heme. The results of the calculation revealed that the substrate oxygenation mechanism had four elementary processes, i.e., (1) formation of [FeOH](3+) and a substrate radical by hydrogen atom abstraction from the substrate caused by [FeO](3+), (2) rotation of the OH group of the sixth ligand of [FeOH](3+) produced by process 1, (3) substrate radical binding with the [FeOH](3+), and (4) elimination of the oxygenated substrate formed at the sixth ligand binding site. The rate-determining step is process 1, hydrogen atom abstraction from the substrate, and the activation energy was determined to be about 15 kcal/mol. For this reason, it is thought that this reaction occurs in vivo.

Binding Sites↗

PubMed2001

XAFS study on active Pr sites in zeolite as a photocatalyst for decomposition of nitrous oxide.

The praseodymium-exchanged mordenite degassed at 873 K acted as a highly active heterogeneous photocatalyst for the stoichiometric decomposition of N2O. Analysis of Pr L3-edge EXAFS revealed that the Pr species were isolated each other in the large channel of zeolite, and that the active Pr species were coordinated by ca. four oxygen atoms and one Al atom. On the other hands, the inactive Pr species are surrounded by ca. 10 oxygens of adsorbed waters. The former low-coordinated Pr species allowed a strong adsorption of N2O, which could be the first step of the decomposition reaction.

Journal Article↗

PubMed2001

Hybrid revascularization feasibility in minimally invasive direct coronary artery bypass grafting combined with percutaneous transluminal coronary angioplasty in patients with acute coronary syndrome and multivessel disease.

OBJECTIVES: We reviewed early and midterm outcome of 11 multivessel-disease acute coronary syndrome patients treated by hybrid revascularization, i.e., initial coronary angioplasty followed by minimally invasive direct coronary artery bypass grafting. We evaluated procedural efficacy and applicability. METHODS: Beginning in August 1997, hybrid revascularization was conducted in 11 multivessel-disease acute coronary syndrome patients--9 men and 2 women with a mean age of 70.3 +/- 9.3 years. Occlusion or stenosis of the target coronary artery was treated by interventional cardiologic techniques and minimally invasive direct coronary artery bypass grafting, and the early and midterm outcome evaluated. Coronary angiography was conducted in all cases at 2 weeks, 6 months, 1 and 3 years postoperatively to evaluate anastomosis and restenosis in treated coronary vessels. RESULTS: Initial intervention succeeded in patients with minimal residual stenosis. Subsequent minimally invasive direct coronary artery bypass grafting involved no complications. Coronary angiography early postoperatively, 6 months, 1 and 3 years later showed grafts patent without stenosis. Percutaneous transluminal coronary angioplasty was reconducted on restenotic lesions in 3 patients, 1 of whom required 3 procedures. CONCLUSIONS: Hybrid revascularization appears safe and effective in coronary revascularization, at least over the short term. Several patients underwent angioplasty for restenosis within 3 years after initial procedure. Overall acceptance of this hybrid method depends on long-term functional success of the 2 procedures. Its major limitation is restenosis of angioplasty sites and the need for repeat procedures.

Aged↗

PubMed2001

Effects of amlodipine on unitary non-L-type high voltage-activated Ca2+ channel currents in differentiated PC12 cells.

Effects of amlodipine on unitary non-L-type high voltage-activated Ca2+ channels (Cav2 channels) were investigated in cell-attached patches of nerve growth factor (NGF)-differentiated PC12 cells. Cav2 channels, mainly composed of N-type channel in our experimental condition, were defined in this study as high voltage-activated Ca2+ channels obtained after selection of patches without L-type channel "mode 2" activity in the presence of 1 microM BayK8644, or L-type channel block by 5 microM nifedipine. At a test potential of +20 mV, they had a unitary current amplitude of approximately 0.5 pA and open time constants of approximately 0.4 ms and approximately 1.1 ms when fit assuming double exponential components. As bath application of amlodipine was ineffective to modify Cav2 channels in the sealed patch, we analyzed the channel activity when giga-seal formation was obtained in the presence of amlodipine (10 microM both in the pipette and bath solution). Amlodipine did not modify the unitary current amplitude but suppressed the channel open probability (NPo) when holding potential was depolarized, shifting the voltage-dependent inactivation curve towards negative potentials by 25mV. Amlodipine-induced suppression of NPo was mainly due to the decreased ratio of sweeps with channel openings (availability) and was not associated with changes in open time constants. These results were consistent with the view that amlodipine prevented channel openings through the high-affinity binding to the inactivated state, as often observed when dihydropyridines block L-type Ca2+ channels.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed2001

Ionic basis for membrane potential changes induced by hypoosmotic stress in guinea-pig ventricular myocytes.

OBJECTIVE: Causal relation between changes in action potentials and activation of several ionic currents during hypoosmotic challenge was investigated. METHODS: We recorded changes in membrane potentials and currents during hypotonic stress in guinea-pig ventricular myocytes using whole-cell patch-clamp technique. RESULTS: Exposure of ventricular myocytes to hypotonic solution (0.6 T) caused initial prolongation ( approximately 107% of control) of action potential duration at 90% repolarization (APD(90)) in 65% of examined myocytes. Later shortening (approximately 75% of control) of APD(90) and depolarization of resting potential (RP) (approximately 4 mV) developed in all cells. Initial prolongation of APD(90) in hypotonic solution was mainly caused by transient activation of Gd(3+)-sensitive non-selective cation (NSC) current. Late changes after approximately 180 s in hypotonic solution were sustained increase in slow component of delayed rectifier K(+) current (I(Ks)) in all cells, and activation of I(Clswell) in 40% of cells. Prevention of APD(90) shortening by chromanol, a selective blocker of I(Ks), was seen in about 40% of myocytes due to short APD in our experimental conditions. Application of 1 mM anthracene-9-carboxylic acid (9-AC) partially inhibited APD shortening in three of seven cells. Depolarization of RP was unaffected by the above-mentioned drugs, but was dependent on [K(+)](o). CONCLUSIONS: Initial prolongation followed by later shortening of APD in hypotonic solution are mostly caused by different sequences of NSC, I(Ks) and I(Clswell) currents activation. Depolarization of RP in hypotonic solution is probably due to dilution of subsarcolemmal K(+) concentration and/or change in permeability ratio for Na(+) and K(+).

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed2001

Relationships between sperm motility characteristics assessed by the computer-aided sperm analysis (CASA) and fertilization rates in vitro.

PURPOSE: Some studies have suggested that computer-aided sperm analysis (CASA) estimates of concentration and movement characteristics of progressively motile spermatozoa are related to fertilization rates in vitro. However, it has also been suggested that the greater number of motility parameters assessed by CASA does not imply more precision in predicting fertility. This study was carried out to investigate the relationships between the CASA estimates and fertilization rates in vitro. METHODS: Semen quality analysis was performed using CASA in 136 in vitro fertilization-embryo transfer (IVF-ET) cycles with at least 3 oocytes collected. The CASA estimates before and after swim-up were compared between 108 cycles with fertilization rate > 50% ("good" group) and 28 cycles with fertilization rate < or = 50% ("poor" group). RESULTS: Before swim-up, there were significant correlations between fertilization rates and CASA estimates, including amplitude of lateral head displacement (ALH) (r = .269), curvilinear velocity (VCL) (r = .297), straight line velocity (VSL) (r = .266), and rapid sprm movement (Rapid) (r = .243). There was also a significant correlation between the fertilization rates and straightness (STR) after swim-up (r = -0.178). As for sperm movement characteristics, there were significant differences of ALH (p < .005), VCL (p < .001), VSL (p < .005), and Rapid (p < .01) between "good" and "poor" groups before swim-up. After swim-up, there were significant differences of VCL (p < .005), average path velocity (VAP) (p < .005), and Rapid (p < .05) between the two groups. CONCLUSIONS: These results indicate that some of the CASA estimates provide reliable estimation of the fertilizing ability of human sperm. There were significant differences of the two sperm movement characteristics, including VCL and Rapid (before and after swim-up), indicating that the total distance traveled by rapid sperm movement might be important in human sperm fertilizing abilities.

Cell Size↗

PubMed2001

A case of traumatic renal graft rupture with salvage of renal function.

An 18-yr-old man received a kidney graft from a 60-yr-old female cadaver donor on February 8, 1996. Postoperative course was uneventful and his serum creatinine level was stable at about 1.8 mg/dL. On April 30, 1999, he collided with a truck while riding a motor cycle. Macroscopic hematuria was observed and CT showed an extensive retroperitoneal hematoma. Because his anemia and hypotension were becoming worse after transfusion of 9 units of blood, he was operated on as an emergency case. A large rupture reaching the pelvis and calyces was observed in the upper pole of the grafted kidney. There were also numerous shallow lacerations, but the major arteries and veins were not injured. The rupture was closed by suturing the renal parenchyma with the peritoneum, and the other shallow lacerations were closed by suturing the renal capsule. The kidney could be salvaged without requiring hemodialysis. The serum creatinine was maintained at 2.1 mg/dL during follow-up. A review of the literature showed that 6 cases of traumatic renal graft rupture with salvage of the kidney have been reported. Our present case was the seventh, and was the most severe graft rupture reported so far.

Accidents, Traffic↗

PubMed2001

Can the proximal isovelocity surface area method calculate stenotic mitral valve area in patients with associated moderate to severe aortic regurgitation? Analysis using low aliasing velocity of 10% of the peak transmitral velocity.

To assess the ability of the proximal isovelocity surface area (PISA) method to accurately measure the stenotic mitral valve area (MVA), and to assess whether aortic regurgitation (AR) affects the calculation, we compared the accuracy of the PISA method and the pressure half-time (PHT) method for determining MVA in patients with and without associated AR by using two-dimensional echocardiographic planimetry as a standard. The study population consisted of 45 patients with mitral stenosis. Seventeen of the 45 patients had associated moderate-to-severe AR. The PISA method was performed using low aliasing velocity (AV) of 10% of the peak transmitral velocity, which provided the most accurate estimation of MVA when compared with planimetry. The maximal radius r of the PISA was measured from the orifice to blue-red aliasing interface. Using the PISA method, MVA was calculated as (2pir(2)) x theta / 180 x AV/Vmax, where theta was the inflow angle formed by mitral leaflets, AV was the aliasing velocity (cm/sec), and Vmax was the peak transmitral velocity (cm/sec). MVA by the PISA method correlated well with planimetry both in patients with AR (r = 0.90, P < 0.001, SEE = 0.17 cm(2)) and without AR (r = 0.92, P < 0.001, SEE = 0.16 cm(2)). However, MVA by the PHT method did not correlate as well with planimetry (r = 0.57, P < 0.05, SEE = 0.37 cm(2)) in patients with associated AR, and the PHT method produced a significant overestimation (24%) of MVA obtained by planimetry in these patients. We conclude that the PISA method allows accurate estimation of MVA and is not influenced by AR.

Adult↗

PubMed2001

Pulmonary CT findings in acute mercury vapour exposure.

AIM: We describe the pulmonary computed tomography (CT) findings in acute mercury poisoning. MATERIALS AND METHODS: Initial (n= 8) and follow-up (n= 6) chest CT examinations in eight patients exposed to mercury vapour while cutting pipes in a sulphuric acid plant were reviewed. Of the eight patients, two were asymptomatic and had normal CT results, two were asymptomatic but had abnormalities on CT, and four had both acute symptoms and positive CT results. The patients were all men whose ages ranged from 37 to 54 years (mean, 49 years). RESULTS: Poorly defined nodules were present in five of six patients with positive CT findings, present alone in two patients or as part of a mixed pattern in three. They were random in distribution. Alveolar consolidation (n= 3) and areas of ground-glass opacity (n= 4) were observed and were more prominent in the most severely affected patients with the highest blood and urine level of mercury, predominantly in the upper and/or middle zone. These abnormal findings on CT resolved with (n= 1) or without (n= 5) steroid therapy. Pathological findings (n= 1) demonstrated acute interstitial changes predominantly with oedema. CONCLUSION: We report CT findings in eight patients acutely exposed to mercury vapour. The pulmonary injury was reversible on CT in these cases. Hashimoto, M. (2001). Clinical Radiology56, 17-21.

Acute Disease↗

PubMed2001

Effect of YM-40461, a novel surfactant secretagogue, on chronic obstructive pulmonary diseases and similar symptoms in guinea pigs.

YM-40461 (1-(2-dimethylaminoethyl)-1-(3,4,5-trimethoxyphenyl)urea, CAS 142912-85-4), is a novel surfactant secretagogue. The effect of YM-40461 on symptoms, e.g. change of airway functions and hypoxemia, were examined using guinea pigs with induced subacute bronchitis. Bronchitic guinea pigs exhibited basal lung resistance (RL) was 0.152 +/- 0.005 cm H2O/ml/s (normal: 0.130 +/- 0.002 cm H2O/ml/s) and basal lung compliance (CL) of 0.455 +/- 0.011 ml/cm H2O (normal: 0.509 +/- 0.009 ml/cm H2O). Although YM-40461 slightly improved the lung resistance in these animals, it improved significantly and dose-dependently the lung compliance (0.468 +/- 0.008 ml/cm H2O for 1 mg/kg, 0.477 +/- 0.008 for 3 mg/kg, 0.490 +/- 0.011 for 10 mg/kg, p < 0.05 at 10 mg/kg) compared to nontreated bronchitic guinea pigs. YM-40461 improved airway functions in bronchitic guinea pigs just as wall as the beta 2-adrenoceptor agonist salbutamol. Additionally, YM-40461 significantly reduced airway hyperreactivity in response to intravenously infused acetylcholine (ACh). Basal PaO2 was 83.1 +/- 0.7 cm H2O in healthy guinea pigs and 71.2 +/- 1.7 cm H2O in bronchitic guinea pigs, indicating hypoxemia. A dose of 10 mg/kg of YM-40461 relieved hypoxemia in these animals with the values returning to 81.8 +/- 1.9 cm H2O (p < 0.05). These results suggest that YM-40461 ameliorates chronic obstructive pulmonary disease (COPD)-like symptoms in bronchitis models due to increased surfactant in the airway.

Acetylcholine↗

PubMed2001

Hyperventilation and cold-pressor stress echocardiography for noninvasive diagnosis of coronary artery spasm.

We report the usefulness of 2-dimensional echocardiography during the cold-pressor test immediately after hyperventilation for noninvasive diagnosis of coronary vasospasm in 43 patients with suspected vasospastic angina. The stress test consisted of hyperventilation for 6 minutes, followed by cold water pressor stress for 2 minutes under continuous electrocardiographic and echocardiographic monitoring. Coronary angiography with an intracoronary injection of acetylcholine was performed within 2 weeks after the stress test. Coronary spasm was observed in 33 patients by angiography. Multivessel spasm was diagnosed in 26 patients by stress echocardiography and in 23 patients by angiography. The stress-induced wall motion abnormalities occurred earlier than the ST-segment changes and chest pain. The wall motion abnormalities shown on the echocardiogram correlated well with the vascular territories of the coronary artery that had the spasm. The sensitivity, specificity, and diagnostic accuracy of hyperventilation and cold-pressor stress echocardiography for detecting vasospastic angina against coronary angiography with an intracoronary injection of acetylcholine were 91%, 90%, and 91%, respectively. However, the sensitivity, specificity, and diagnostic accuracy of hyperventilation and cold-pressor stress electrocardiography for detecting vasospastic angina were 48%, 100%, and 60%, respectively. No major side effects were observed during or after the stress test. Echocardiographic monitoring during the stress test detected spasm unaccompanied by either ST- segment changes or chest pain and revealed the location of multivessel coronary spasm. Hyperventilation and cold-pressor stress echocardiography is thus a noninvasive and useful tool for the diagnosis of vasospastic angina.

Aged↗

PubMed2001

Usefulness of transvaginal hydrolaparoscopy in investigating infertile women with Chlamydia trachomatis infection.

BACKGROUND: A new technique called transvaginal hydrolaparoscopy (THL) was recently developed for the exploration of the tubo-ovarian structures in infertile patients without obvious pelvic pathology. This study was performed to investigate the usefulness of THL to evaluate Chlamydia trachomatis tubal infertility. METHODS: Forty-one women with primary and secondary infertility participated in this study. Fourteen had past C. trachomatis infection. In 38 (92.7%) of the 41, access to the pouch of Douglas was obtained. In total, 71 (93.4%) out of 76 adnexa were clearly visualized. Thirty-seven patients were analysed and compared their tubal passages and peritubal adhesions using both hysterosalpingography (HSG) and THL. Twenty-four tubes from 14 patients with past C. trachomatis infection and 44 tubes from 23 patients without a history of C. trachomatis infection were compared. RESULTS: For the diagnosis of the tubal passage, there were no significant differences in the discrepancy rates between HSG and THL, in patients with and without past C. trachomatis infection. In 14 (58.3%) of the 24 tubes from patients with past C. trachomatis infection and in eight (18.2%) of the 44 tubes from patients without infection, peritubal adhesion was diagnosed only by THL. There was a significant difference in the discrepancy rates of the diagnosis of peritubal adhesion between HSG and THL in the two groups (P = 0.0007 ). CONCLUSIONS: These results suggest that C. trachomatis infection is highly associated with peritubal adhesion which is difficult to diagnose by HSG. Therefore, in C. trachomatis antibody-positive patients, exclusion of tubal pathology by THL or standard laparoscopy should be carried out to consider appropriate treatments. Although THL is not a substitute for laparoscopy, it can be proposed as a first line procedure in the early stages of the infertility investigation.

Adult↗

PubMed2001

Mechanical properties of tendon and aponeurosis of human gastrocnemius muscle in vivo.

Load-strain characteristics of tendinous tissues (Achilles tendon and aponeurosis) were determined in vivo for human medial gastrocnemius (MG) muscle. Seven male subjects exerted isometric plantar flexion torque while the elongation of tendinous tissues of MG was determined from the tendinous movements by using ultrasonography. The maximal strain of the Achilles tendon and aponeurosis, estimated separately from the elongation data, was 5.1 +/- 1.1 and 5.9 +/- 1.6%, respectively. There was no significant difference in strain between the Achilles tendon and aponeurosis. In addition, no significant difference in strain was observed between the proximal and distal regions of the aponeurosis. The results indicate that tendinous tissues of the MG are homogeneously stretched along their lengths by muscle contraction, which has functional implications for the operation of the human MG muscle-tendon unit in vivo.

Achilles Tendon↗

PubMed2001

Stress-induced ST-segment elevation following myocardial infarction and its role in wall motion abnormality, myocardial ischemia and viability: comparison of response to exercise, dobutamine and dipyridamole.

Stress-induced ST-segment elevation following myocardial infarction (MI) has been correlated with myocardial ischemia, viability and wall motion abnormality, but its mechanism is still unclear, so the present study compared ST-segment elevation and wall motion response during exercise, dobutamine and dipyridamole stresses. Twenty-five patients with their first anterior MI underwent exercise, dobutamine and dipyridamole echocardiography on different days 4-6 weeks after MI. Left ventricular wall motion was analyzed using 5-grade/16-segment model and myocardial ischemia was considered as a worsening of the wall motion score index (WMSI) during the stress test; myocardial viability was defined as a reduction of WMSI during low dose dobutamine. Dyskinesis formation was defined by visual analysis as akinesis that became dyskinetic or if the dyskinesis worsened. Both exercise and dobutamine induced ST-segment elevation, but dipyridamole did not. There was no significant difference in the degree of ST-segment elevation between the patients with and without myocardial ischemia or dyskinesis formation. Exercise induced a higher ST-segment elevation in patients with myocardial viability than those without (0.17+/-0.09 mV vs 0.09+/-0.07 mV, p<0.05). Exercise-induced ST-segment elevations correlated with dobutamine-induced ST-segment elevations (p<0.01), changes in heart rate (p<0.05) and systolic blood pressure (p<0.05). In conclusions, stress-induced ST-segment elevation does not correlate with either myocardial ischemia or stress-induced dyskinesis, but may be associated with myocardial viability.

Cardiotonic Agents↗