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  • 1
    Electronic Resource
    Electronic Resource
    Influence of QRS Duration on the Prognostic Value of T Wave Alternans (2002)
    Oxford, UK : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 13 (2002), S. 0 
    Details
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: T Wave Alternans and QRS Duration. Introduction: T wave alternans (TWA) is a promising new noninvasive marker of arrhythmia vulnerability that quantifies beat-to-beat changes in ventricular repolarization. Secondary repolarization abnormalities are common in subjects with wide QRS complexes. However, the relationship between TWA and QRS prolongation has not been evaluated. The goal of this study was to determine if QRS prolongation influences the prevalence or prognostic value of TWA. Methods and Results: The study consisted of 108 consecutive patients with coronary artery disease and left ventricular ejection fraction ≤40% who were referred for electrophysiologic studies. Patients underwent TWA testing using bicycle ergometry in the absence of beta-blockers or antiarrhythmic drugs. The primary endpoint was the combined incidence of death, sustained ventricular arrhythmias, and appropriate implantable cardioverter defibrillator therapy. The prognostic value of TWA was assessed in the entire cohort and in two subgroups: QRS 〈 120 msec (normal, n = 62) and QRS ≥ 120 msec (prolonged, n = 46). TWA (hazard ratio 2.2, P = 0.03) and QRS prolongation (hazard ratio 2.2, P = 0.01) were both significant and independent predictors of arrhythmic events. QRS prolongation had no effect on the prevalence of positive TWA tests (QRS 〈 120 msec: 48%, QRS ≥ 120 msec: 50%, P = NS). TWA was a highly significant predictor of events in patients with a normal QRS (hazard ratio 5.8, P = 0.02). In contrast, TWA was not useful for risk stratification in subjects with QRS prolongation (hazard ratio 1.1, P = 0.8). Conclusion: TWA is useful only for risk stratification in the absence of QRS prolongation. The presence of QRS prolongation and left ventricular ejection fraction ≤40% may be sufficient evidence of an adverse prognosis that additional risk stratification is not useful or necessary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1540-8167.2002.00770.x
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  • 2
    Electronic Resource
    Electronic Resource
    Enhanced Detection of Arrhythmia Vulnerability Using T Wave Alternans, Left Ventricular Ejection Fraction, and Programmed Ventricular Stimulation: (2004)
    350 Main Street , Malden , MA 02148-5018 , USA , and 9600 Garsington Road , Oxford OX4 2DQ , UK . : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 15 (2004), S. 0 
    Details
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: In previous studies, the prognostic value of T wave alternans (TWA) was similar to that of programmed ventricular stimulation (PVS). However, presently it is unclear if TWA and PVS identify the same patients or provide complementary risk stratification information. In addition, the effects of left ventricular ejection fraction (LVEF) on the prognostic value of TWA are unknown. The aim of this study was to determine if combined assessment of TWA, LVEF, and PVS improves arrhythmia risk stratification. Methods and Results: This was a prospective study of 144 patients with coronary artery disease and LVEF ≤40% who were referred for PVS for standard clinical indications. The endpoint was the combined incidence of death, sustained ventricular arrhythmias, and appropriate implantable cardioverter defibrillator (ICD) therapy. TWA (hazard ratio 2.2, P = 0.03) and PVS (hazard ratio 1.9, P = 0.05) both were significant predictors of endpoint events, and TWA was the only independent predictor. LVEF markedly influenced the prognostic value of TWA, which was a potent predictor of events in subjects with LVEF between 30% and 40% (event rates: TWA+ 36%, TWA- 0%, P = 0.001) but did not predict events in subjects with LVEF 〈30% (hazard ratio 1.1, P 〉 0.5). PVS successfully identified additional low-risk patients within the cohort with negative or indeterminate TWA results (hazard ratio 4.7, P = 0.015) but did not provide incremental prognostic information for TWA+ patients (hazard ratio 0.9, P 〉 0.5). Conclusion: The combined use of TWA, LVEF, and PVS is a promising new approach to arrhythmia risk stratification that permits identification of high-risk and very-low-risk patients. (J Cardiovasc Electrophysiol, Vol. 15, pp. 170-176, February 2004)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1540-8167.2004.03428.x
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  • 3
    Electronic Resource
    Electronic Resource
    Lack of Benefit of an Active Pectoral Pulse Generator on Atrial Defibrillation Thresholds (2002)
    Oxford, UK : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 13 (2002), S. 0 
    Details
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Effect of an Active Can on Atrial DFTs. Introduction: Atrial defibrillation can be achieved with standard implantable cardioverter defibrillator leads, which has led to the development of combined atrial and ventricular devices. For ventricular defibrillation, use of an active pectoral electrode (active can) in the shocking pathway markedly reduces defibrillation thresholds (DFTs). However, the effect of an active pectoral can on atrial defibrillation is unknown. Methods and Results: This study was a prospective, randomized, paired comparison of two shock configurations on atrial DFTs in 33 patients. The lead system evaluated was a dual-coil transvenous defibrillation lead with a left pectoral pulse generator emulator. Shocks were delivered either between the right ventricular coil and proximal atrial coil (lead) or between the right ventricular coil and an active can in common with the atrial coil (active can). Delivered energy at DFT was 4.2 ± 4.1 J in the lead configuration and 5.0 ± 3.7 J in the active can configuration (P = NS). Peak current was 32% higher with an active can (P 〈 0.01), whereas shock impedance was 18% lower (P 〈 0.001). Moreover, a low threshold (〈 3 J) was observed in 61% of subjects in the lead configuration but in only 36% in the active can configuration (P 〈 0.05). There were no clinical predictors of the atrial DFT. Conclusion: These results indicate that low atrial DFTs can be achieved using a transvenous ventricular defibrillation lead. Because no benefit was observed with the use of an active pectoral electrode for atrial defibrillation, programmable shock vectors may be useful for dual-chamber implantable cardioverter defibrillators.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1540-8167.2002.00332.x
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  • 4
    Electronic Resource
    Electronic Resource
    Exercise is Superior to Pacing for T Wave Alternans Measurement in Subjects with Chronic Coronary Artery Disease and Left Ventricular Dysfunction (2002)
    Oxford, UK : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 13 (2002), S. 0 
    Details
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Exercise vs Pacing for TWA Measurement. Introduction: T wave alternans (TWA) is a heart rate-dependent marker of vulnerability to ventricular arrhythmias. Atrial pacing and exercise both are used as provocative stimuli to elicit TWA. However, the prognostic value of the two testing methods has not been compared. The aim of this prospective study was to compare the prognostic value of TWA measured during bicycle exercise and atrial pacing in a large cohort of high-risk patients with ischemic heart disease and left ventricular dysfunction. Methods and Results: This was a prospective study of 251 patients with coronary artery disease and left ventricular dysfunction who were referred for electrophysiologic studies (EPS) for standard clinical indications. Patients underwent TWA testing using bicycle ergometry (exercise TWA, n = 144) and/or atrial pacing (pacing TWA, n = 178). The primary endpoint was the combined incidence of death, sustained ventricular arrhythmias, and appropriate implantable cardioverter defibrillator therapy. The predictive value of exercise and pacing TWA for EPS results and for endpoint events was determined. Exercise and pacing TWA both were significant predictors of EPS results (odds ratios 3.0 and 2.9 respectively, P 〈 0.02). Kaplan-Meier survival analysis of the primary endpoint revealed that exercise TWA was a significant predictor of events (hazard ratio 2.2, P = 0.03). In contrast, pacing TWA had no prognostic value for endpoint events (hazard ratio 1.1, P = 0.8). Conclusion: TWA should be measured during exercise when it is used for clinical risk stratification. EPS results may not be an adequate surrogate for spontaneous events when evaluating new risk stratification tests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1540-8167.2002.00845.x
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  • 5
    Electronic Resource
    Electronic Resource
    Dual Left Anterior Descending Coronary Artery: A Rare Coronary Anomaly (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of interventional cardiology 13 (2000), S. 0 
    Details
    ISSN: 1540-8183
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We were asked to review the coronary angiogram of a patient showing a dual left anterior descending (LAD) arterial supply anomaly. This prompted a review of the database at Ochsner Foundation Hospital for congenital coronary anomalies in general and similar cases in particular. Between 1989 and 1996, 15,714 coronary catheterizations were performed. We found 134 anomalies (0.85%); the presence of a dual supply to the usual LAD territory was found in 2 patients (0.013%). In this report, we present the absolute and relative incidence of the individual patterns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8183.2000.tb00276.x
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  • 6
    Electronic Resource
    Electronic Resource
    ROOF BOUNDARY EXTRACTION USING MULTIPLE IMAGES (2003)
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 18 (2003), S. 0 
    Details
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Urban area building extraction is one of the most challenging problems in photogrammetry. Well-extracted buildings are needed for a variety of applications, such as cartography, building GIS databases for cities, and urban planning. This paper presents a new technique to extract 3D building wire-frames using a robust multi-image line-matching algorithm. Although one pair of images is adequate to find the 3D position of two visibly corresponding image features, it is not sufficient to solve the general building extraction problem due to obscured parts in the building. Four images are used in this research to extract the building wire-frames. First the images are segmented into regions. Regions are then classified into roof regions and non-roof regions based on their size, shape, and intensity values. The roof region boundary pixels are located and used to find the region perimeters. Region correspondence is solved in a pair-wise mode over all images using the epipolar constraint, region size, region shape, and region intensity values. Image lines within the corresponding regions are matched over all images simultaneously by first creating a plane for each region line. Planes are then intersected simultaneously and geometric consistency is used to determine acceptance or rejection. Results with high overlap and sidelap aerial images are presented and evaluated. The results show the completeness and accuracy that this method can provide for extracting complex urban buildings. The average coordinate accuracy is about 0·8 m using 1:4000 scale aerial photographs scanned at 30 μm. Six buildings were examined; the line detection rate is 98%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/0031-868X.t01-1-00003
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  • 7
    Electronic Resource
    Electronic Resource
    Naegele's rule: a reappraisal (2001)
    Oxford, UK : Blackwell Science Ltd
    BJOG 108 (2001), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.2001.00166.x
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  • 8
    Electronic Resource
    Electronic Resource
    Helminthosporium leaf blight resistance and agronomic performance of wheat genotypes across warm regions of South Asia (2004)
    Oxford, UK : Blackwell Publishing Ltd
    Plant breeding 123 (2004), S. 0 
    Details
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Helminthosporium leaf blight (HLB) is the most important disease constraint to wheat (Triticum aestivum L.) cultivation in the eastern Gangetic Plains of South Asia. A Helminthosporium Monitoring Nursery (HMN) including potential adapted and exotic sources of HLB resistance was developed in Bangladesh, India and Nepal to assess the stability of genetic resistance across locations. The 8th, 9th and 10th HMN assessed the HLB resistance and agronomic traits of 17 wheat genotypes across 20 environments of Bangladesh, India and Nepal in the 1999-2000, 2000-2001 and 2001-2002 cropping seasons, respectively. The area under the disease progress curve (AUDPC) for HLB, grain yield, thousand-kernel weight (TKW), days to heading, days to maturity, and plant height were examined. The 17 genotypes showed a range of variability for disease and agronomic characters. Disease severity (AUDPC) differed in the 3 years and showed the highest values in 2002. The increase in AUDPC in 2002 caused the lowest grain yield, with an average 18% reduction due to HLB. A few genotypes (SW 89-5422, Yangmai-6 and Ning 8201) appeared to have stable HLB resistance across environments. However, most of the higher-yielding genotypes, except BL 1883, were unstable. The results suggest that careful selection of HLB resistance with acceptable grain yield, TKW and plant height may be possible using the wheat genotypes included in the HMN.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0523.2004.01006.x
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  • 9
    Electronic Resource
    Electronic Resource
    Hazards of submental tracheal intubation (2004)
    Oxford, UK : Blackwell Science Ltd
    Anaesthesia 59 (2004), S. 0 
    Details
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2044.2004.03725.x
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  • 10
    Electronic Resource
    Electronic Resource
    Over-the-counter H2-receptor antagonists do not compromise intragastric pH control with proton pump inhibitors (2002)
    Oxford UK : Blackwell Science Ltd.
    Alimentary pharmacology & therapeutics 16 (2002), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Proton pump inhibitors effectively suppress intragastric acid. Nocturnal acid breakthrough occurs on any dosing regimen of oral proton pump inhibitors. Histamine2-receptor antagonists (H2RA) suppress intragastric acidity independently of meals and help to control nocturnal acid breakthrough. Because proton pump inhibitors require an acid intragastric milieu for activation, nocturnal dosing of H2RA might decrease the effect of proton pump inhibitors taken in the morning by decreasing their gastric-acid-driven activation.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:Assess intragastric acid control on omeprazole, 20 mg, taken every morning, after variable dosing of over-the-counter famotidine, 10 mg.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Twelve Helicobacter pylori-negative, healthy volunteers received omeprazole, 20 mg, every morning before breakfast for 15 days. Baseline studies on omeprazole, 20 mg, in the morning, were done on day 7. On nights between days 8–9, 11–12 and 14–15, famotidine, 10 mg at bedtime, and 10 mg at bedtime and/or at 05.30 h, was given in a three-way, crossover, double-blind randomized design. Intragastric pH monitoring was performed on days 9, 12 and 15, starting at 08.00 h.〈section xml:id="abs1-4"〉〈title type="main"〉Results:Percentage times intragastric pH 〈 4 on omeprazole, 20 mg, in the morning of the day after receiving famotidine, 10 mg, at bedtime (58.6 ± 4.8); at 05.30 h (54.1 ± 5.1); or at bedtime and at 05.30 h (54.3 ± 5.0) did not differ significantly (P=0.65) from percentage times intragastric pH on day 7 of omeprazole, 20 mg, in the morning (49.5 ± 5.1).〈section xml:id="abs1-5"〉〈title type="main"〉Conclusion:Concerns over inhibition of next-day daytime proton-pump inhibitor effect should not preclude use of nocturnal H2RAs in patients with gastro-oesophageal reflux disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.2002.01171.x
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