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S Carstensen

Publications and source records attributed to S Carstensen.

At least 19 recordsLinked to original sources
PubMed2000

Comparison of methods of fractional area change for detection of regional left ventricular dysfunction.

Three methods for assessment of fractional area change (FAC) and conventional versus cross-sectional segmentation were compared under conditions known to occur frequently during stress echocardiography. Quantitative analysis of 80 echocardiograms obtained from healthy subjects, patients with left ventricular (LV) dysfunction and after coronary artery bypass grafting included segmental and cross-sectional FACs by the centroid method with fixed and floating reference and a method with floating external reference. All segmental and cross-sectional FACs were equally sensitive to LV dysfunction, and segmental FACs failed to accurately predict the location of coronary lesions. The centroid method with floating reference and cross-sectional FACs were the least affected by surgery induced intrathoracic heart motion. In moderate to severe LV dysfunction FAC by the centroid method with floating reference and cross sections were rarely within normal limits. Cross-sectional FACs may prove to be useful in stress echocardiography. For viability studies segmental FAC by fixed reference appears to be the method of choice.

Adult↗
PubMed2000

Atrioventricular plane motion during dobutamine-atropine stress echocardiography: the biphasic response in healthy subjects revisited.

This study was undertaken to establish normal values for the systolic atrioventricular plane motion (AVPM) from base to apex during dobutamine-atropine stress echocardiography (DASE) and to compare them with those of patients with coronary artery disease. The AVPM was measured at baseline, low dose and peak dobutamine-atropine infusion in 20 patients referred for coronary angiography and in 20 control subjects. Atrioventricular plane motion was measured at the posterior, anterior, septal, and lateral positions of the mitral annulus in the apical 2- and 4-chamber views by an observer blinded to clinical and angiographic data. In healthy subjects undergoing DASE, AVPM initially increased but subsequently decreased to below baseline values at peak stress. Atrioventricular plane motion at any stage and the changes therein during DASE were within the normal reference interval in the majority of patients. In conclusion, AVPM decreased during DASE in healthy subjects and was not a sensitive marker of coronary artery disease.

Adrenergic beta-Agonists↗
PubMed1999

Biosynthesis and localization of phosphatidyl-scyllo-inositol in barley aleurone cells.

A novel isomer of phosphatidylinositol (PI), phosphatidyl-scyllo-inositol, was characterized in the aleurone cells of barley seeds. In this investigation, the subcellular localization of scyllo-PI and the relative rates of biosynthesis and accumulation of [32P]phosphoric acid ([32Pi])-labeled scyllo- and myo-phosphoinositides in the plasma membrane and intracellular membrane pools were investigated. About 25% of the [32Pi]-labeled phospholipids were present in plasma membrane and 75% in intracellular membranes. Incorporation of [32Pi] into scyllo-PI was greater than into myo-PI in both the plasma membranes and intracellular membranes at all time points investigated, thus suggesting a higher rate of biosynthesis; however, the data do not preclude reduced breakdown of labeled scyllo-PI as a contributing factor. In vitro studies were conducted to investigate the presence of cytidinediphosphate diacylglycerol (CDP-DG):scyllo-inositol 3-phosphatidyltransferase (scyllo-PI synthase) and to optimize enzymatic activity. The inclusion of nonionic detergents (Brij 58 and Triton X-100) effected significant enhancement in the biosynthesis of scyllo-PI, whereas anionic, cationic, and zwitterionic detergents had little or no effect. This is the first evidence for CDP-DG:scyllo-inositol 3-phosphatidyltransferase activity.

CDP-Diacylglycerol-Inositol 3-Phosphatidyltransfer↗
PubMed1998

Fluorodeoxyglucose uptake in dysfunctional myocardium subtended by an occluded coronary artery. Relation to dobutamine contractile reserve and Sestamibi uptake.

BACKGROUND: Myocardial segments with impaired function may have the potential for functional recovery. Augmented exogenous glucose uptake in relation to blood flow estimated by [2-18F]2-fluorodeoxyglucose (FDG) and positron emission tomography (PET) frequently indicates functional reversibility. The spectrum of FDG uptake levels in relation to Sestamibi uptake and dobutamine contraction reserve in areas with impaired function subtended by an occluded coronary artery has never been reported. METHODS AND RESULTS: Seventeen patients with stable angina pectoris and dysfunctional myocardium subtended by an occluded coronary artery were studied with FDG-PET, low-dose dobutamine echocardiography and Sestamibi-Single Photon Emission Computerized Tomography. In a 16 segment model dysfunctional myocardial segments showed a normally distributed FDG uptake ranging from 34% to 150% when normalized to peak segmental Sestamibi uptake. Low FDG uptake was associated with both lack of dobutamine induced contractile reserve and low Sestamibi uptake (in 73% of the segments) whereas high FDG uptake displayed both contractile reserve and Sestamibi uptake (57%). Segments with intermediate FDG uptake had either contractile reserve or a preserved Sestamibi uptake (62%). CONCLUSION: Dysfunctional myocardium subtended by an occluded coronary artery represents a continuum of metabolic states with a high degree of heterogeneity with regard to contractile reserve and Sestamibi uptake.

Adult↗
PubMed1998

Long-term effects on cardiac output and peripheral resistance in patients treated with enalapril after acute myocardial infarction. CONSENSUS II Multi-Echo Study Group. Cooperative New Scandinavian Enalapril Survival Study.

In the Cooperative New Scandinavian Enalapril Survival Study (CONSENSUS II), in which enalapril treatment was initiated intravenously within 24 h after acute myocardial infarction, there was a neutral effect on 6-month mortality, whereas a beneficial effect on the progression of congestive heart failure was noted. We studied the effect of enalapril on left ventricular systolic function in terms of cardiac output and mean acceleration time measured by pulsed-wave Doppler in the left ventricular outflow tract and peripheral resistance. Early angiotensin-converting enzyme inhibition after acute myocardial infarction did not result in a general improvement of cardiac output. However, a small increase in cardiac output was observed in a subgroup of enalapril-treated patients with ejection fraction > or = 45%, probably due to a reduction in peripheral resistance in these patients.

Aged↗
PubMed1997

Myocardial sestamibi single-photon emission tomography: variations in reference values with gender, age and rest versus stress?

Reference data files support the evaluation of myocardial perfusion single-photon emission tomography (SPET). The aim of this study was to create a large reference data base for technetium-99m sestamibi SPET, age and gender matched to the general patient population. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a likelihood of coronary artery disease of less than 5% underwent rest and maximal exercise 99mTc-sestamibi SPET with a 2-day protocol and 180 degrees elliptical rotation. The normalized activity values of 99mTc-sestamibi in the inferior wall differed significantly between men and women. Age variations were found for men in the anterior wall. Normalized activity values in all four walls were strikingly similar during rest and stress. Our results suggest that the use of reference files in 99mTc-sestamibi SPET requires a gender- and, for males, possibly an age-matched reference population. Different reference files at rest and during stress might not be necessary.

Adult↗
PubMed1996

Effect of enalapril initiated early after acute myocardial infarction on heart failure parameters, with reference to clinical class and echocardiographic determinants. CONSENSUS II Multi-Echo Study Group.

BACKGROUND AND HYPOTHESIS: Although the angiotensin-converting enzyme inhibitor enalapril has recently been shown to reduce mortality and the need for hospitalization in patients with left ventricular dysfunction and congestive heart failure, this drug was found to have no significant impact on short-term mortality after acute myocardial infarction (AMI) in the CONSENSUS II trial. The effect of enalapril initiated early after AMI on clinical and echocardiographic determinants of left ventricular (LV) function was studied in a subset of patients from CONSENSUS II. METHODS: Symptoms and signs of heart failure were classified as NYHA and dyspnea classes. Echocardiography included LV end-systolic volumes (ESV) and end-diastolic volumes (EDV), as well as ejection fraction (EF), wall motion index (WMI), and mitral flow indices. In all, 428 patients were included and followed for an average of 5.1 months by serial examinations, starting 2-5 days after myocardial infarction (MI) and repeated after 1 month and at the completion of the study. RESULTS: There was no beneficial effect of enalapril on clinically determined function. Changes (i.e., changes in NYHA class) in the functional status remained correlated with changes in echocardiographic determinants throughout the study in patients belonging to the placebo group: EDV index (r = 0.36, p = 0.002, ESV index (r = 0.49, p < 0.001), EF (r = -0.41, p < 0.001), and WMI (r = 0.29, p = 0.008). In a stepwise logistic regression model, the best baseline parameters to predict NYHA class at final visit in all patients were age (p = 0.014) and ESV index (p = 0.001). CONCLUSION: Enalapril treatment for an average period of 5.1 months following MI resulted in no clinically significant beneficial effects on NYHA and dyspnea class. Changes in clinical function class were correlated with changes in echocardiographic determinants in placebo-treated patients, but not in patients given enalapril.

Aged↗
PubMed1996

Benefit of converting enzyme inhibition on left ventricular volumes and ejection fraction in patients receiving beta-blockade after myocardial infarction. CONSENSUS II multiecho study group.

Beta-blockers reduce infarct size and improve survival after acute myocardial infarction (MI). Post-MI angiotensin-converting enzyme inhibition also improves survival and may attenuate left ventricular (LV) dilatation. We evaluated the effect of early enalapril treatment on LV volumes and ejection fraction (EF) in patients on concomitant beta-blockade after MI. Intravenous enalaprilat or placebo was administered <24 hours after MI and was continued orally for 6 months. LV volumes were assessed by echocardiography 3 +/- 2 days, 1 and 6 months after MI. Change in LV diastolic volume during the first month was attenuated with enalapril (2.7 vs placebo 6.5 ml/m2 change; p < 0.05), and significantly lower LV diastolic and systolic volumes were observed with enalapril treatment compared with placebo at 1 month (enalapril 47.21 23.9 vs placebo 53.1/29.2 ml/m2; p < 0.05) and at 6 months (enalapril 47.9/24.8 vs placebo 53.8/29.6 ml/m2; p < 0.05). EF was also significantly higher 1 month after MI in these patients (enalapril 50.4% vs placebo 46.4%; p < 0.05). Our date demonstrate that early enalapril treatment attenuates LV volume expansion and maintains lower LV volumes and higher EF in patients receiving concurrent beta-blockade after MI. A possible additive effect of combined therapy should be evaluated prospectively.

Administration, Oral↗
PubMed1995

Dobutamine-atropine stress echocardiography in asymptomatic healthy individuals. The relativity of stress-induced hyperkinesia.

BACKGROUND: Interpretation of dobutamine-atropine stress echocardiography (DASE) is based on the assumption that the normal response to dobutamine-atropine infusion is characterized by increased systolic thickening and motion of the left ventricular (LV) walls, whereas a reduction or no change is considered indicative of coronary artery disease. The aim of this study was to quantitatively assess changes in LV dimension and wall motion patterns during DASE in a healthy population. METHODS AND RESULTS: Forty-two asymptomatic voluntary subjects (22 men) with a mean age of 59 years (range, 31 to 79 years) and a likelihood of < 5% for coronary artery disease underwent DASE with digital recording of two-dimensional and M-mode echocardiography at baseline and low-dose and peak infusion rates. Mean end-diastolic and end-systolic LV diameters and areas decreased and wall thicknesses increased progressively throughout the test. Wall motion and thickening increased from baseline to low-dose infusion in nearly all subjects. However, from low-dose to peak infusion, the mean absolute wall motion and relative wall thickening decreased by 13.1% (95% CI, 2.7 to 23.5) and 21.4% (95% CI, 6.4 to 36.4) regardless of age, sex, or use of atropine. Changes in fractional shortening and absolute wall thickening varied considerably, with a decrease observed in 15 and 13 individuals (36% and 31%), respectively. CONCLUSIONS: In healthy subjects, measures of wall motion and wall thickening increased from baseline to low-dose infusion but decreased from low-dose to peak infusion. These findings call for revision of the assumptions on which the common analysis of DASE is based.

Age Factors↗
PubMed1995

Effects of early enalapril treatment on global and regional wall motion in acute myocardial infarction. CONSENSUS II Multi Echo Study Group.

Angiotensin-converting-enzyme inhibitor therapy can preserve left ventricular (LV) function and geometric features and improve survival in subsets of patients with acute myocardial infarction (AMI). We investigated the effect of enalapril treatment initiated < 24 hours after AMI on global and regional echocardiographic wall motion indexes obtained at 2 to 5 days and at 1 and 6 months in 428 consecutive patients enrolled in the randomized, placebo-controlled Cooperative New Scandinavian Enalapril Survival Study II. In anterior AMIs, the non-infarct-zone index deteriorated in the placebo group but remained unchanged in the enalapril-treated group (0.18 vs 0.02; p < or = 0.05), an effect related to attenuated LV volume expansion. No treatment effects were observed in nonanterior AMIs or in the entire unselected population. Thus in an unselected population with AMI, early enalapril treatment had no effect on LV function; yet in patients with anterior infarcts, LV function was maintained through preservation of function in the noninfarcted myocardium.

Aged↗
PubMed1995

Reproducibility of digital exercise echocardiography.

We determined the intra, inter-observer and temporal variability of upright bicycle exercise echocardiography in 50 consecutive patients with suspected coronary heart disease. Using significant artery stenoses as reference, the sensitivity of digital exercise echocardiography was 89% and the specificity 92%. Regarding the presence or absence of exercise-induced ischaemia, intra-observer agreement was 86% (73-94% with 95% confidence limits, kappa value (K) 0.70 (0.50-0.91)). Inter-observer agreement between two independent observers was 92 (81-98)% (K = 0.81 (0.63-0.99)). Temporal variability was examined by repeating exercise echocardiography after one week in 30 stable patients; it demonstrated 90 (78-97)% agreement (K = 0.71 (0.40-1.00)). The inter-observer agreement appeared to be lower in patients or myocardial segments with wall motion abnormalities at rest (86% and 82%, respectively) than in patients or segments with normal myocardial function at rest (96% and 94%, respectively); ns, P < 0.05, respectively). Analysis of specific regions showed a significantly higher level of agreement (P < 0.05) regarding exercise-induced ischaemia in segments supposed to be supplied by the circumflex branch of the left coronary artery (96%) than in the perfusion bed of the left anterior descending branch (87%) and right coronary artery (88%). Comparing estimated values of echocardiographic ejection fraction, analysis of intra-observer variability showed a correlation coefficient of 0.91 and 95% confidence limits of a single estimate of ejection fraction of +/- 10.3%. Corresponding analyses of inter-observer and temporal variability showed correlation coefficients of 0.93 and 0.84, respectively, and 95% confidence limits of single estimates of ejection fraction of +/- 9.6% and +/- 13.0%, respectively. Thus, the diagnostic result and the reproducibility of digital exercise echocardiography are satisfactory and comparable with those obtained by myocardial scintigraphy. However, approximately 10% of the examination results may be reversed when the test is repeated or reevaluated by the same or by another observer. The result seems to be less reproducible in patients with abnormal wall motion at rest than in patients with normal myocardial function before exercise.

Adult↗
PubMed1995

Left ventricular volumes, ejection fraction, and plasma proatrial natriuretic factor (1-98) after withdrawal of enalapril treatment initiated early after myocardial infarction. CONSENSUS II Multi-Echo Study Group.

OBJECTIVES: To assess whether the reduction in left ventricular dilatation after acute myocardial infarction obtained by early administration of angiotensin converting enzyme inhibitors depends on continuous treatment. DESIGN: Prospective observational and cross sectional study of withdrawal of randomised treatment with enalapril or placebo. PATIENTS: 106 patients on 6 months trial treatment after an acute myocardial infarction. MAIN OUTCOME MEASURES: Left ventricular volumes and ejection fraction as assessed by echocardiography and circulating proatrial natriuretic factor (1-98) before and 4-6 weeks after withdrawal of treatment. RESULTS: There were no significant changes (mean (SD)) in left ventricular systolic (0.7 (4.7) ml/m2) and diastolic (0.4 (6.6) ml/m2) volume indices, ejection fraction (-0.9 (6)%), and proatrial natriuretic factor (172 (992) pmol/l) after withdrawal of enalapril. The significantly lower left ventricular volumes observed with 6 months of enalapril therapy after acute myocardial infarction, as compared with placebo, were maintained 6 weeks after drug withdrawal. CONCLUSION: The results show that the benefit of 6 months of enalapril treatment initiated early after myocardial infarction is maintained for at least 6 weeks after drug withdrawal, suggesting that the treatment effect on left ventricular structure is not reversed by changes in loading conditions caused by subsequent drug withdrawal.

Atrial Natriuretic Factor↗
PubMed1994

[Dobutamine stress echocardiography. Use of dobutamine stress echocardiography in diagnosis and assessment of ischemic heart disease].

Dobutamine stress echocardiography (DSE) is a new diagnostic method for evaluation of patients with known or suspected coronary artery disease. We studied 30 consecutive patients referred for evaluation of chest pain. Coronary angiography was carried out in 28 patients. DSE was performed the following day. Readable echocardiographic recordings were obtained in all patients. Blinded wall motion analysis revealed a diagnostic sensitivity of 91% (95% confidence limits: 79-100%) for dobutamine stress echocardiography using coronary angiography as reference. No severe adverse events or arrhythmias occurred. It is concluded that DSE is well tolerated, feasible and has a high sensitivity for detecting coronary artery disease.

Adult↗
PubMed1993

Attenuation of left ventricular dilatation after acute myocardial infarction by early initiation of enalapril therapy. CONSENSUS II Multi-Echo Study Group.

This trial investigated the effect of enalapril, administered early, on left ventricular (LV) volumes after myocardial infarction. Four hundred twenty-eight patients included in the Cooperative New Scandinavian Enalapril Survival Study (CONSENSUS II) were examined with echocardiography within 5 days, at 1 month and at 6 months after myocardial infarction. Enalaprilat (1 mg) or placebo infusion was initiated within 24 hours after infarction, followed by oral treatment to a target dose of 20 mg/day. A significant attenuation of LV dilatation was noted at 1 month in patients treated with enalapril compared with those receiving placebo. Changes in LV end-diastolic volume indexes during the first month were (mean +/- SEM) 5.7 +/- 1.0 ml/m2 for the placebo group and 1.9 +/- 0.8 ml/m2 for the enalapril group (p < 0.02). Changes in LV end-systolic volume indexes were 3.1 +/- 0.8 and 0.5 +/- 0.6 ml/m2, respectively (p < 0.02). The between-group difference was most marked in patients with anterior wall infarction (p < 0.005). Volume changes beyond the first month were similar in both groups but the differences observed at 1 month were maintained. The larger volumes in the placebo versus enalapril group were significant or borderline significant at 1 and 6 months. Thus, enalapril treatment initiated early after myocardial infarction and continued for 6 months can attenuate LV dilatation during the first month resulting in smaller LV volumes after 1 and 6 months.

Aged↗
PubMed1992

Structure-activity relationships of epoxides: induction of sister-chromatid exchanges in V79 cells by enantiomeric epoxides.

Analysis of SCE frequencies in Chinese hamster V79 cells was used to investigate the influence of the stereoisomeric forms of epoxides in mammalian genotoxicity tests. The SCE-inducing potency of 12 pairs of (R)- and (S)-enantiomeric epoxides which differed in the degree of substitution of the oxirane ring was determined. Of these, 2 pairs of epoxides failed to induce SCE. Different SCE-inducing potencies between the (R)- and (S)-enantiomers were shown for 5 epoxides. This study demonstrates that stereoselectivity might play an important role in genotoxicity testing of chemicals with asymmetric C atoms.

Alkylation↗
PubMed1991

Structure-activity relationships of epoxides: induction of sister-chromatid exchanges in Chinese hamster V79 cells.

Analysis of SCE frequencies in Chinese hamster V79 cells was used to investigate structure-activity relationships of epoxides in mammalian cells. For this purpose the SCE-inducing potency of 58 epoxides was determined. Of these, 16 failed to induce SCE in V79 cells. According to the substitution of the oxirane ring the results show general agreement with results obtained in the Ames test. Mono-substituted epoxides had the highest genotoxic potency compared to di- and tri-substituted epoxides. In detail, there are differences in genotoxic potency between bacteria and mammalian cells which can be explained by differences in the cellular uptake of the compounds and by detoxification reactions.

Animals↗