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Mishra JP, Acio E, Heo J, Narula J, Iskandrian AE. Impact of stress single-photon emission computed tomography perfusion imaging on downstream resource utilization. Am J Cardiol 1999; 83:1401-3, A8. [PMID: 10235101 DOI: 10.1016/s0002-9149(99)00106-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study shows that in patients with intermediate pretest probability of coronary artery disease stress single-photon emission computed tomography perfusion imaging decreases the rate of coronary angiography and coronary revascularization and is economically a superior strategy to routine coronary angiography.
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Cohen Y, Acio E, Heo J, Hughes E, Narula J, Iskandrian AE. Comparison of the prognostic value of qualitative versus quantitative stress tomographic perfusion imaging. Am J Cardiol 1999; 83:945-8, A9. [PMID: 10190415 DOI: 10.1016/s0002-9149(98)01056-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study compared qualitative assessment of exercise thallium imaging to quantitative assessment in predicting outcome in 713 patients with 78% prevalence of coronary artery disease by coronary angiography; during a mean follow-up of 52 months, there were 106 hard cardiac events (death or nonfatal myocardial infarction). The qualitative method provided important prognostic information; however, unlike the quantitative technique, less patients were assigned to either the low- or high-risk group and proportionally more patients into the intermediate-risk group, which may limit the clinical usefulness of the technique.
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Heo J, Holbrook GP. Regulation of 2-carboxy-D-arabinitol 1-phosphate phosphatase: activation by glutathione and interaction with thiol reagents. Biochem J 1999; 338 ( Pt 2):409-16. [PMID: 10024517 PMCID: PMC1220067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
2-Carboxy-D-arabinitol 1-phosphate (CA1P) phosphatase de- grades CA1P, an inhibitor associated with the regulation of ribulose bisphosphate carboxylase/oxygenase in numerous plant species. CA1P phosphatase purified from Phaseolus vulgaris was partially inactivated by oxidizing conditions during dialysis in air-equilibrated buffer. Phosphatase activity could then be stimulated 1.3-fold by dithiothreitol and also by addition of reduced thioredoxin from Escherichia coli. These effects were enhanced synergistically by the positive effector, fructose 1, 6-bisphosphate (FBP). Most notably, CA1P phosphatase activity was stimulated up to 35-fold by glutathione, and was sensitive to the ratio of reduced (GSH) to oxidized (GSSG) forms. At concentrations of glutathione approximating measured levels in chloroplasts of P. vulgaris (5 mM total S), CA1P phosphatase exhibited >20-fold stimulation by a change in the redox status of glutathione from 60 to 100% GSH. This stimulation was augmented further by reduced E. coli thioredoxin. In contrast, FBP, which activates CA1P phosphatase under reducing conditions, was strongly inhibitory in the presence of GSSG. We propose that glutathione may have an appreciable role in the light/dark regulation of CA1P phosphatase in vivo. A model for the reversible activation of CA1P phosphatase by GSH was derived based upon the various responses of the enzyme's activity to a range of thiol reagents including N-ethylmaleimide, 5, 5'-dithiobis-(2-nitrobenzoic acid) and arsenite. These data indicate that the bean enzyme contains two physically distinct sets of thiol groups that are critical to its redox regulation.
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Amanullah AM, Heo J, Acio E, Narula J, Iskandrian AE. Predictors of outcome of medically treated patients with left main/three-vessel coronary artery disease by coronary angiography. Am J Cardiol 1999; 83:445-8, A9. [PMID: 10072239 DOI: 10.1016/s0002-9149(98)00883-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
This study examined the prognostic value of single-photon emission computed tomography in angiographically high-risk patients with left main and/or 3-vessel coronary artery disease who were treated medically. Multivariable Cox survival analysis revealed the single-photon emission computed tomography score (based on size of perfusion abnormality, multivessel abnormality, left ventricular dilation, and lung uptake) as the only independent predictor of outcome.
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105
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Mishra J, Acio ER, Heo J, Iskandrian AE. Comparison of the polar maps method and the summed stress score for predicting outcome in medically treated patients with coronary artery disease. Am J Cardiol 1999; 83:258-9, A5. [PMID: 10073831 DOI: 10.1016/s0002-9149(98)00832-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study showed that quantitative analysis of SPECT perfusion images provide comparable prognostic information to summed stress score in medically treated patients with coronary artery disease.
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106
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Heller GV, Iskandrian AE, Orlandi C, Ahlberg AW, Heo J, Mann A, White MP, Gagnon A, Taillefer R. Fasting and nonfasting iodine-123-idophenylpentadecanoic acid myocardial SPECT imaging in coronary artery disease. J Nucl Med 1998; 39:2019-22. [PMID: 9867134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
UNLABELLED Iodine-123-labeled idophenylpentadecanoic acid (IPPA) metabolic imaging has been shown to be clinically useful for the identification of myocardial viability in patients with coronary artery disease and left ventricular dysfunction. Imaging is usually performed under fasting conditions since nonfasting conditions may affect myocardial uptake of 123I-IPPA. The purpose of this study was to examine the impact of dietary condition on 123I-IPPA metabolic imaging. METHODS Forty patients with stable coronary artery disease underwent, in randomized order and on separate days, 123I-IPPA SPECT myocardial imaging under fasting and nonfasting conditions. Patients were injected with 123I-IPPA (4-5 mCi) at rest with imaging performed at 4 (initial) and 30 (delay) min. For each image (initial and delay images), 10 segments were analyzed by three experienced observers without knowledge of patient identity or dietary condition using a 5-point grading system (O = no uptake to 4 = normal uptake). A summed global score was obtained for each image by adding the scores for all 10 segments. Image quality was assessed using a 3-point grading system. RESULTS Visual agreement for normal and abnormal segments between fasting and nonfasting conditions was 82% (kappa = 0.63). There were no significant differences in the summed global scores for both conditions. Image quality was equivalent for both conditions in 65% of cases and superior under the nonfasting condition in 25% of cases. CONCLUSION Image quality as well as the presence, location and severity of defects are similar under fasting and nonfasting conditions with 123I-IPPA. Therefore, fasting is not necessary before 123I-IPPA SPECT imaging for the assessment of myocardial viability.
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Amanullah AM, Heo J, Iskandrian AE. Impact of exercise single-photon emission computed tomographic imaging on appropriateness of coronary revascularization. Am J Cardiol 1998; 81:1489-91. [PMID: 9645902 DOI: 10.1016/s0002-9149(98)00219-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study examined the predictors of early coronary revascularization in 816 patients with chest pain syndromes who had coronary artery disease by angiography and exercise single-photon emission computed tomography (SPECT) thallium imaging. Multivariate analysis of clinical, stress, nuclear, and catheterization variables revealed the presence of SPECT reversibility as the most powerful predictor (chi-square = 43) of early revascularization.
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108
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Amanullah A, Heo J, Narula J, Skandrian A. Predictors of outcome of medically treated patients with left main/3-vessel disease by coronary angiography. J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(98)80124-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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109
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Kothan M, Bagheri B, Hessen S, Verma A, Cordero M, Ahmar W, Marchtinski F, Gottlieb C, Heo J, Iskandnan A. Outcome of patient with life threatening ventricular arrhythmias. J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(98)81425-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ogilby JD, Kegel JG, Heo J, Iskandrian AE. Correlation between hemodynamic changes and tomographic sestamibi imaging during dipyridamole-induced coronary hyperemia. J Am Coll Cardiol 1998; 31:75-82. [PMID: 9426021 DOI: 10.1016/s0735-1097(97)00448-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES The purposes of this study were to examine the effects of dipyridamole infusion on hemodynamic variables and to compare these changes with myocardial perfusion. BACKGROUND Dipyridamole stress testing with myocardial perfusion imaging is widely used in the assessment of patients with known or suspected coronary artery disease (CAD). Few studies, however, have correlated the hemodynamic effects of dipyridamole using invasive monitoring with perfusion patterns in patients with chest pain syndromes. METHODS Hemodynamic measurements were made in the cardiac catheterization laboratory with a Swan-Ganz thermodilution catheter before, during and after infusion of dipyridamole (142 microg/kg body weight per min for 4 min). Technetium-99m sestamibi was injected 3 min after the completion of the infusion. RESULTS There were 20 patients with and 6 without CAD, as demonstrated by angiography. Compared with baseline values, dipyridamole resulted in an increase in pulmonary capillary wedge pressure (54 +/- 78% vs. 32 +/- 26%, p = NS), cardiac index (36 +/- 21% vs. 40 +/- 18%, p = NS) and stroke volume index (16 +/- 18% vs. 40 +/- 18%, p = NS) and a decrease in systemic vascular resistance (22 +/- 13% vs. 24 +/- 11%, p = NS), aortic pressure (2 +/- 9% vs. 0 +/- 6%, p = NS) and pulmonary vascular resistance (19 +/- 25% vs. 11 +/- 32%, p = NS) in patients with and without CAD. The peak effect of dipyridamole on heart rate, systemic vascular resistance and pulmonary capillary wedge pressure was evident at 3 min after infusion in 70% of patients. Aminophylline, given to 20 patients, improved hemodynamic variables within 2 min. The single-photon emission computed tomographic sestamibi images were normal in the 6 patients without and abnormal in the 18 patients with CAD. CONCLUSIONS Dipyridamole-induced coronary hyperemia produces mild hemodynamic changes in patients with and without CAD; these changes are at or near peak effect at 3 min after infusion and are rapidly reversed by aminophylline.
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Galatro K, Narula J, Dourdoulis P, Heo J, Acio E, Brozena S, Chaudhry F, Iskandrian A. Wall motion assessment by gated SPECT perfusion imaging in patients with ischemic cardiomyopathy. J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(98)80846-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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112
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Narula J, Mishra J, Dawson S, Heo J, Dhawan R, Amanullah A, Chaudhry F, Brozena S, Iskandrian A. Novel use of dual isotope gated SPECT imaging with low- and high dose dobutamine stress for characterization of stunned, hibernating remodeled and non-viable myocardium. J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(98)80847-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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113
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Nallamothu N, Johnson JH, Bagheri B, Heo J, Iskandrian AE. Utility of stress single-photon emission computed tomography (SPECT) perfusion imaging in predicting outcome after coronary artery bypass grafting. Am J Cardiol 1997; 80:1517-21. [PMID: 9416927 DOI: 10.1016/s0002-9149(97)00772-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Previous studies have examined the predictors of outcome in medically treated patients with coronary artery disease (CAD). There is limited information on predictors of outcome after coronary artery bypass grafting (CABG). This study examined the predictors of outcome of 255 patients with CAD, at a mean time of 5 years after CABG for angina pectoris. The 255 patients underwent coronary angiography and stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging after CABG. During a mean follow-up of 41 +/- 28 months after stress testing, there were 34 hard events (24 cardiac deaths and 10 nonfatal myocardial infarctions). The hemodynamics during stress testing, and age and gender were not predictors of events. The SPECT variables of multivessel perfusion abnormality, perfusion deficit size, and increased lung thallium uptake were predictors of death and total events by uni- and multivariate survival analysis. There were 14 events in 45 patients (31%) with multivessel abnormality and increased lung thallium uptake, 14 events in 101 patients (14%) with either multivessel abnormality or increased lung uptake, and 6 events in 109 patients (6%) with neither of these 2 variables (p = 0.0001). The annual mortality and total event rates were 7.5% and 9.5% with both variables, 3.4% and 4.3% with either variable, and 0.6% and 1.7% with neither of the variables (p = 0.01). Thus, stress SPECT perfusion imaging is useful to stratify patients after CABG into low, intermediate, and high risk groups for future cardiac events.
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Nallamothu N, Bagheri B, Acio ER, Heo J, Iskandrian AE. Prognostic value of stress myocardial perfusion single photon emission computed tomography imaging in patients with left ventricular bundle branch block. J Nucl Cardiol 1997; 4:487-93. [PMID: 9456188 DOI: 10.1016/s1071-3581(97)90006-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Left bundle branch block (LBBB) may occur with or without structural heart disease. In patients with coronary artery disease the presence of LBBB is associated with an increased risk of cardiovascular events. METHODS AND RESULTS This study examined the outcome of 293 medically treated patients with LBBB and symptoms who were undergoing stress thallium-201 single photon emission computed tomography imaging. One hundred seventy-three men and 120 women with an age range of 67 +/- 9 years and a pretest probability of coronary artery disease of 77% +/- 28% were studied. During a mean follow-up of 33 months 58 hard cardiac events (death or nonfatal myocardial infarction) and 112 total events (hard events, coronary angioplasty, coronary bypass surgery, or cardiac transplantation) occurred. Univariate and multivariate Cox survival analysis with clinical, stress, hemodynamic, and single photon emission computed tomography variables identified the perfusion defect size (chi square = 27, p = 0.0001) and increased lung thallium uptake as the most important independent predictors of hard or total cardiac events. The hard event-free survival rate was 91% in patients with no or small defects (<15% of left ventricular myocardium) and 72% in patients with large defects (p = 0.0001, RR = 3.2, 95% CI 1.7 to 5.9). The total event-free survival rate was 81% in patients with small defects and 48% in patients with large defects (p = 0.0001, RR = 2.7, 95% CI 1.9 to 4.0). The total event rate was 54% in patients with large perfusion defects and increased lung uptake and 17% in patients with no or small abnormality and normal lung thallium uptake (p = 0.0001). CONCLUSION Single photon emission computed tomography perfusion imaging is useful in predicting outcome in patients with LBBB and intermediate pretest probability of coronary artery disease. The size of perfusion abnormality and lung thallium uptake stratified patients into high and low risk groups with a threefold difference in hard and total cardiac events.
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Iskandrian AE, Heo J, Nallamothu N. Detection of coronary artery disease in women with use of stress single-photon emission computed tomography myocardial perfusion imaging. J Nucl Cardiol 1997; 4:329-35. [PMID: 9278880 DOI: 10.1016/s1071-3581(97)90111-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Heo J, Kim GH, Lee KS, Go WU, Ju HJ, Park SK, Song CS, Song GA, Cho M, Yang US, Moon HK, Kim YK. Effect of Ca2+ channel blockers, external Ca2+ and phospholipase A2 inhibitors on t-butylhydroperoxide-induced lipid peroxidation and toxicity in rat liver slices. Korean J Intern Med 1997; 12:193-200. [PMID: 9439155 PMCID: PMC4531990 DOI: 10.3904/kjim.1997.12.2.193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES This study was undertaken to examine the effect of oxidant on lipid peroxidation and lethal cell injury in rat liver slices. METHODS t-Butylhydroperoxide (t-BHP) was employed as a model of an oxidant. The lipid peroxidation and lethal cell injury were estimated by measuring the formation of malondialdehyde (MDA) and lactate dehydrogenase (LDH) release, respectively. RESULTS t-BHP increased lipid peroxidation and LDH release in a dose-dependent manner over concentrations of 0.5-10 mM. t-BHP-induced lipid peroxidation was completely prevented by an antioxidant, N,N-diphenyl-p-phenylenediamine (DPPD), but LDH release was partially decreased. Both t-BHP-induced lipid peroxidation and LDH release were significantly protected by iron chelator, deferoxamine, sulfhydryl reducing agent, dithiothreitol and glutathione. Ca2+ channel blockers, verapamil, diltiazem and nifedipine exerted a significant protective effect against t-BHP-induced lipid peroxidation and LDH release. By contrast, addition of external Ca2+ chelator, ethylene glycol bis(b-aminoethyl ether)-N,N-tetraacetic acid (EGTA) did not alter t-BHP-induced lipid peroxidation, whereas t-BHP-induced lethal cell injury was significantly prevented. Phospholipase A2 (PLA2) inhibitors, mepacrine and butacaine produced a partial protective effect. CONCLUSIONS These results suggest that t-BHP induces cell injury by lipid peroxidation-dependent and -independent mechanisms which can be partially prevented by Ca2+ channel blockers and PLA2 inhibitors.
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Heo J, Powers J, Iskandrian AE. Exercise-rest same-day SPECT sestamibi imaging to detect coronary artery disease. J Nucl Med 1997; 38:200-3. [PMID: 9025735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
UNLABELLED This study examined the results of exercise-rest same-day SPECT protocol in 193 patients, of whom 132 had coronary artery disease (CAD) by angiography (> or = 50% diameter stenosis), and 61 had a low pretest probability of CAD. METHODS The rest study was combined with first-pass radionuclide angiography using the multicrystal gamma camera in 72 patients. RESULTS The sensitivity of SPECT was 76% (25/33 patients) in patients with one-vessel, 84% in patients with two-vessel (38/45) and 98% in patients with three-vessel CAD (53/54) (P = 0.01 versus one- or two-vessel CAD). The sensitivity of SPECT in patients with CAD was higher than ST depression (88% versus 28%, P = 0.001). The exercise was submaximal in 53 patients (40%). The perfusion defects were reversible (complete or partial) in 80 patients and fixed in 36 patients. The left ventricular ejection fraction was 50 +/- 12% in patients with reversible defects (n = 44) and 39 +/- 9% in patients with fixed defects (n:19) (P = 0.0004). The normalcy rate in subjects with a low pretest probability of CAD was 95% (53 of 61 subjects). CONCLUSION The exercise-rest same-day sestamibi protocol provides high diagnostic accuracy for CAD detection. The protocol may eliminate the need for rest studies in patients with normal exercise images, help improve laboratory throughput and lower costs.
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Gioia G, Bagheri B, Gottlieb CD, Schwartzman DS, Callans DJ, Marchlinski FE, Heo J, Iskandrian AE. Prediction of outcome of patients with life-threatening ventricular arrhythmias treated with automatic implantable cardioverter-defibrillators using SPECT perfusion imaging. Circulation 1997; 95:390-4. [PMID: 9008454 DOI: 10.1161/01.cir.95.2.390] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND In the present study, we examined the predictors of outcome of 103 patients with coronary artery disease and left ventricular dysfunction who had life-threatening ventricular arrhythmias and were treated with implantable cardioverter-defibrillators with the use of single-photon emission computed tomography (SPECT). METHODS AND RESULTS During a mean follow-up of 29 months, there were 29 cardiac deaths. In comparison with patients who died, survivors had less diabetes mellitus (45% versus 19%, P < .007), higher left ventricular ejection fraction (23 +/- 9% versus 27 +/- 11%, P = .04), and fewer perfusion defects as determined with stress SPECT (15 +/- 5 versus 12 +/- 5, P < .004). Most of the perfusion defects were fixed, indicative of scarring; the extent of reversible defects did not differ (2 +/- 3 in survivors and 3 +/- 4 in nonsurvivors). Multivariate Cox survival analysis identified the number of fixed defects as the only independent predictor of death (chi 2 = 10, P = .002). There were six deaths among 42 patients (14%) with < 8 fixed defects compared with 23 deaths among 61 patients (38%) with > or = 8 defects (P = .005). The 4-year survival was better in patients with < 8 segmental fixed defects than in those with > or = 8 fixed defects (80% versus 36%) (chi 2 = 8, P = .005). CONCLUSIONS The myocardial perfusion pattern is an important determinant of outcome in patients with life-threatening ventricular arrhythmias who are treated with a implantable cardioverter-defibrillator. The extent of scarring separates patients into high- and low-risk groups with a 2.7-fold difference in death rate.
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Krauss LM, Liu H, Heo J. Dirty Black Holes and Hairy Black Holes. PHYSICAL REVIEW LETTERS 1996; 77:5164-5167. [PMID: 10062732 DOI: 10.1103/physrevlett.77.5164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Abstract
Myocardial hibernation is hypoperfused dysfunctional myocardium that has the potential to recover function after coronary revascularization. Although recovery of regional function after revascularization is the gold standard for assessing the diagnostic accuracy of various techniques, improvements of EF, symptoms, and survival are fundamental end points. Despite important differences in the markers of viability by positron-emission tomography, single-photon emission tomography, two-dimensional echocardiography, and magnetic resonance imaging, their positive and negative predictive values in nonrandomized studies are fairly comparable. Assessment of myocardial viability may be clinically important in many patients but especially in those with EF < 30% and congestive heart failure. The degree of improvement in EF after coronary revascularization depends on the extent of hibernation, the suitability of coronary structure for revascularization, the lack of perioperative infarction, the completeness of revascularization, and the long-term patency of grafts.
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Tartagni F, Fallani F, Corbelli C, Monetti N, Piovaccari G, Marzocchi A, Zannoli R, Branzi A, Magnani B, Heo J, Iskandrian AS. Dynamic planar myocardial perfusion imaging in patients with one-vessel disease with intracoronary injection of technetium 99m teboroxime during papaverine-induced coronary hyperemia. Am Heart J 1996; 132:1042-7. [PMID: 8892781 DOI: 10.1016/s0002-8703(96)90019-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This study examined the imaging results and kinetics of technetium 99m teboroxime after its intracoronary injection during papaverine-induced coronary hyperemia in patients with one-vessel disease before and after coronary angioplasty. Thirteen patients with > or = 90% diameter stenosis of either the left anterior descending or the left circumflex coronary artery were included. Two patients were excluded because of ventricular tachycardia during papaverine injection in one patient and unsuccessful angioplasty in the second patient. One mCi of technetium 99m teboroxime was injected into the left main coronary artery during coronary hyperemia induced by intracoronary injection of papaverine. Dynamic acquisition in a frame mode (20 sec/frame) was performed for 5 minutes in the left anterior oblique projection with a multicrystal gamma camera before and after successful angioplasty. Ischemic:normal count ratio increased from 0.75 +/- 0.4 before to 1.00 +/- 0.50 after angioplasty (p < 0.1). The T 1/2 of teboroxime was 6.5 +/- 1.5 min in the normal zone and 7.2 +/- 1.9 min in the ischemic zone (p, NS). Perfusion defects were visible in the territory of the stenosed coronary artery in 9 of 11 patients before angioplasty and in 7 of 11 patients after angioplasty. The image quality was excellent in all studies. Thus this study shows that performing dynamic imaging with intracoronary injection of technetium 99m teboroxime is feasible. This technique may be useful to study the impact of angioplasty on coronary flow and tracer kinetics.
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Aksut SV, Pancholy S, Johnson J, Walter JD, DiMarzio D, Cave V, Cassel D, Heo J, Iskandrian AS. Comparison of left ventricular performance in healthy young women and men during exercise. J Nucl Cardiol 1996; 3:415-21. [PMID: 8902674 DOI: 10.1016/s1071-3581(96)90077-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Previous studies show sex-related differences in left ventricular (LV) response to exercise. It is not clear, however, whether these differences are also seen in younger healthy subjects. METHODS AND RESULTS This study examined the changes in LV performance during dynamic upright exercise in 11 healthy men and 19 healthy young women according to the Bruce protocol and an individualized ramp protocol. There were no significant differences between the two protocols for either men or women in heart rate, blood pressure, LV ejection fraction (EF) (measured by ambulatory nuclear detector), and measured oxygen consumption. The peak oxygen consumption was higher in men than in women (44 +/- 13 vs 36 +/- 9 ml/kg/min; p < 0.05), but the peak heart rate, systolic blood pressure, and EF were similar. The change in EF (from rest to exercise) was 19% +/- 8% in men and 19% +/- 11% in women with the Bruce protocol (difference not significant) and 26% +/- 9% in men and 19% +/- 6% in women with the ramp protocol (difference not significant). At peak exercise, both men and women showed an increase in end-diastolic volume (29% +/- 14% vs 23% +/- 11%; difference not significant) and a decrease in end-systolic volume (41% +/- 15% vs 43% +/- 21%) (difference not significant). The increase in cardiac output during exercise was due to an increase in heart rate and stroke volume in both men and women. At submaximal exercise, however, the decrease in end-systolic volume was less in women than in men (p < 0.05). CONCLUSIONS There are no sex-related differences in compensatory mechanism during dynamic exercise in healthy subjects. The changes in contractility and LV volume are not affected by the exercise protocol.
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Nallamouthu N, Araujo L, Russell J, Heo J, Iskandrian AE. Prognostic value of simultaneous perfusion and function assessment using technetium-99m sestamibi. Am J Cardiol 1996; 78:562-4. [PMID: 8806344 DOI: 10.1016/s0002-9149(96)00366-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This study examines the prognostic value of simultaneous perfusion and function assessment in 412 patients. The exercise perfusion pattern was a stronger predictor of events (mostly acute nonfatal myocardial infarcts) than resting ejection fraction.
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