bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implantation Techniques and Chronic Lead Parameters of Biventricular Pacing Dual‐Chamber Defibrillators
Authors: DAOUD EMILE G. , KALBFLEISCH STEVEN J. , HUMMEL JOHN D. , WEISS RAUL , AUGUSTINI RALPH S. , DUFF STEVEN B. , POLSINELLI GEORGIA , CASTOR JOHN , META TEJAS 
Published: December 2004

Biventricular Pacing.
Introduction: The aim of this study is to describe implantation techniques and lead performance for biventricular pacing, dual‐chamber implantable cardioverter defibrillators (ICDs). Methods and Results: A dual‐chamber ICD with biventricular pacing was implanted in 87 patients with congestive heart failure (ejection fraction: 0.21 ± 0.09), prolonged QRS duration (161 ± 22 msec), and an indication for ICD therapy. Left ventricular pacing was achieved with a thoracotomy approach (n = 21) or a nonthoracotomy approach (n = 66). With a thoracotomy, biventricular devices were implanted successfully in all patients. During follow‐up (17 ± 11 months), 9 patients died (43%), 2 underwent transplantation, and 2 required left ventricular lead revision. At last follow‐up, biventricular sensing and capture threshold were 11 ± 5 mV and 1.5 ± 0.8 V, respectively. For nonthoracotomy procedures, two types of coronary sinus (CS) leads were implanted: an over‐the‐wire lead (n = 45) and a shaped lead (n = 21). The rate of successful implantation (overall: 89%) (over‐the‐wire 93% vs shaped 81%; P = 0.1) and durations for CS lead placement (66 ± 50 vs 58 ± 34 min, P = 0.6) and the procedure (133 ± 58 vs 129 ± 33 min, P = 0.8) were not different between the two CS leads. During follow‐up (11 ± 9 months), 9 patients died (14%), and the shaped CS lead dislodged in 3 patients (3 shaped vs 0 over‐the‐wire, P = 0.01). At last follow‐up, biventricular sensing and capture threshold were 10 ± 4 mV and 1.8 ± 0.7 V, respectively, and there was no difference between over‐the‐wire and shaped leads. By multivariate analysis, mortality was associated with absence of spironolactone therapy but not procedural features. Conclusion: Nonthoracotomy CS lead implantation is feasible, with a success rate of about 90% and few adverse events. For the remaining 10%, a thoracotomy approach can be completed safely in these ill patients without increased risk for death.
Use of Intracardiac Echocardiography for Prediction of Chronic Pulmonary Vein Stenosis After Ablation of Atrial Fibrillation
Authors: SAAD EDUARDO B. , COLE CHRISTOPHER R. , MARROUCHE NASSIR F. , DRESING THOMAS J. , PEREZ‐LUGONES ALEJANDRO , SALIBA WALID I. , SCHWEIKERT ROBERT A. , KLEIN ALLAN , RODRIGUEZ LEONARDO , GRIMM RICHARD , TCHOU PATRICK , NATALE ANDREA 
Published: December 2004

Prediction of PV Stenosis After Ablation.
Introduction: Measurements of pulmonary vein (PV) flow with intracardiac echocardiography (ICE) immediately before and after PV isolation may be a useful method for predicting which patients will develop chronic PV stenosis. Methods and Results: We assessed preablation and postablation flows in each of the four PVs using a phase‐array ICE catheter in 95 patients (mean age 52 ± 13) undergoing atrial fibrillation ablation. The ostium of each of the PVs was defined using angiography, electrical mapping, and ICE imaging. Ostial electrical isolation of all PVs was achieved using a 4‐mm cooled‐tip radiofrequency ablation catheter. Change in PV flow, when present, was examined as both an absolute value and as a percentage of the baseline flow. All patients underwent spiral computed tomography (CT) scans of the PVs 3 months after the procedure for detection of stenosis. The average preablation diastolic flows for the left superior, left inferior, right superior, and right inferior veins were 0.56, 0.54, 0.47, and 0.45 m/sec, respectively. These values increased to 0.74, 0.67, 0.58, and 0.59 m/sec postablation (P < 0.001). Of 380 PVs ablated, the CT scans revealed 2 (1%) with severe (> 70%) stenosis, 13 (3%) with moderate (51%–70%) stenosis, and 62 (16%) with mild (≤ 50%) stenosis. The r value between flow and stenosis was only 0.09 (P = NS). Conclusion: Acute changes in PV flow immediately after ostial PV isolation do not appear to be a strong predictor of chronic PV stenosis.
Transmural Action Potential Changes Underlying Ventricular Electrical Remodeling
Authors: LIBBUS IMAD , ROSENBAUM DAVID S. 
Published: December 2004

Introduction: Although it is well established that alterations in heart rate or activation sequence induce electrical remodeling in the atria, electrical remodeling in the ventricle is poorly understood.
Methods and Results: To determine the changes in cellular repolarization that underlie ventricular electrical remodeling caused separately by altered heart rate and activation sequence, optical action potentials were recorded simultaneously from 256 sites spanning the transmural wall of the arterially perfused canine wedge preparation

(n = 15)

. Action potentials were compared from the same sites under identical conditions [endocardial pacing, cycle length (CL) = 1,000 msec], before and after an intervening 20‐ to 60‐minute period of remodeling induced by (1) rapid pacing (CL = 300 msec) with no change in activation sequence; (2) altered activation sequence (epicardial pacing) with no change in rate; or (3) no change in rate or activation sequence (control). Action potential duration (APD) shortened by

24.8 ± 4.8 msec

following a period of rapid heart rate

(P < 0.05)

but prolonged (by

12.7 ± 1.8 msec

) following a period of altered activation sequence

(P < 0.05)

. Hence, even after restoration of baseline heart rate and activation sequence, there were persistent changes in APD from baseline, indicative of electrical remodeling. Moreover, the orientation of the maximum APD gradient across the transmural wall changed more significantly following heart rate remodeling (by

27.7°± 4.9°, P < 0.05

) than following activation sequence remodeling (by

12.3°± 2.4°, P < 0.05

).
Conclusion: Persistent changes in ventricular repolarization can be induced by surprisingly short periods of altered rate or activation sequence. In contrast to atrial remodeling, electrical remodeling in the ventricle can result in prolonged APD (with altered activation sequence) or reversal of APD gradient orientation (with rapid rate), suggesting that the nature of ventricular electrical remodeling induced by these two perturbations is different.
(J Cardiovasc Electrophysiol, Vol. 14, pp. 394‐402, April 2003)
Implantable Cardioverter Defibrillator in High‐Risk Long QT Syndrome Patients
Authors: ZAREBA WOJCIECH , MOSS ARTHUR J. , DAUBERT JAMES P. , HALL W. JACKSON , ROBINSON JENNIFER L. , ANDREWS MARK 
Published: December 2004

Introduction: Implantable cardioverter defibrillators (ICDs) are increasingly being used in high‐risk long QT syndrome (LQTS) patients, but there are limited data regarding clinical experience with this therapeutic modality. The aim of this study is to describe the clinical characteristics of 125 LQTS patients treated with ICDs compared with LQTS patients having similar risk indications who were not treated with ICDs.
Methods and Results: Among 125 LQTS patients with ICDs, there were 54 cardiac arrest survivors, 19 patients who had ICDs implanted due to recurrent syncope despite beta‐blocker therapy, and 52 patients with ICDs implanted due to other reasons, including syncope and LQTS‐related sudden death in a close family member. Patients with cardiac arrest and those with recurrent syncope despite beta‐blocker therapy (n = 73) were compared to 161 LQTS patients who had similar indications (89 cardiac arrest and 72 recurrent syncope despite beta‐blocker therapy) but did not receive ICDs. Total mortality was the endpoint of the analysis. There was 1 (1.3%) death in 73 ICD patients followed an average of 3 years, whereas there were 26 deaths (16%) in non‐ICD patients during mean 8‐year follow‐up (P = 0.07 from log rank test from Kaplan‐Meier curves).
Conclusion: ICDs provide an important therapeutic option to prevent sudden arrhythmic death in high‐risk LQTS patients. A long‐term prospective study is needed to determine the benefit of this therapeutic modality in LQTS patients.
(J Cardiovasc Electrophysiol, Vol. 14, pp. 337‐341, April 2003)
Functional Genomic Study on Atrial Fibrillation Using cDNA Microarray and Two‐Dimensional Protein Electrophoresis Techniques and Identification of the Myosin Regulatory Light Chain Isoform Reprogramming in Atrial Fibrillation
Authors: LAI LING‐PING , LIN JIUNN‐LEE , LIN CHICH‐SHENG , YEH HUEI‐MING , TSAY YEOU‐GUANG , LEE CHWEN‐FANG , LEE HSIAO‐HUI , CHANG ZEE‐FEN , HWANG JUEY‐JEN , SU MING‐JAI , TSENG YUNG‐ZU , HUANG SHOEI K. STEPHEN 
Published: December 2004

Introduction: Functional and structural changes of atrial tissue occur during the natural course of atrial fibrillation (AF), and these changes may contribute to further AF. We investigated the changes in AF tissue using cDNA microarray and two‐dimensional protein electrophoresis techniques. Methods and Results: We established a porcine model of AF by rapid right atrial appendage pacing at a rate of 600/min. Atrial tissue was obtained after rapid atrial depolarization for 6 weeks. Microarrays containing 6,035 cDNA clones were used to evaluate the alterations of mRNA. Two‐dimensional protein electrophoresis was performed to compare protein patterns. In cDNA microarray studies, we identified 387 genes with significant change in the left atrium and 81 genes in the right atrium. Among the genes, the ventricular isoform of the myosin regulatory light chain (MLC‐2V) showed the greatest fold of change (9.4 and 7.3 in the left and right atrium, respectively). In protein electrophoresis, the expression levels of three protein spots spanning from 18 to 20 kDa in the acidic region (PI 4.5–5.0) were specifically elevated in the AF group. Interestingly, through tandem mass spectrometric analysis, these three spots were identified as MLC‐2V. Thus, MLC‐2V expression at the mRNA and protein levels corresponded well, and both indicated a significant increase in AF. Conclusion: Both cDNA microarray and two‐dimensional polyacrylamide protein electrophoresis studies revealed characteristic changes in AF tissue. We demonstrated the reprogramming of myosin regulatory light chain isoform composition, with a significant increase of its ventricular isoform (MLC‐2V). (J Cardiovasc Electrophysiol, Vol. 15, pp. 214‐223, February 2004)
Impact of Catheter Ablation on Pulmonary Vein Morphology and Mechanical Function
Authors: SCHWARTZMAN DAVID , KANZAKI HIDEAKI , BAZAZ RAVEEN , GORCSAN JOHN 
Published: December 2004

Introduction: Previous reports have documented that radiofrequency catheter ablation of pulmonary veins induces a significant increase in the peak velocity of transvenous blood flow. Although the magnitude of the increase infers a state of pulmonary vein stenosis, there have been no reports of direct visualization of the ablation zone. Methods and Results: In each of 23 subjects, the myocardium investing one or more pulmonary veins (total of 42 veins) was electrically isolated by applying a confluent circumferential ablation lesion to the atrial side of the venoatrial junction. Doppler measurements of transvenous flow velocity were made before and after ablation using phased‐array intracardiac echocardiography. Direct visualization of the ablation zone was performed using rotating intracardiac echocardiography, permitting assessment of shape, cross‐sectional area, phasic variation in cross‐sectional area, and wall thickness. In a subset of 5 subjects, a more detailed assessment of the ablation and contiguous regions was performed using three‐dimensional echocardiography (rotating transducer). Prior to ablation, venoatrial junctions demonstrated noncircular shape and marked phasic variation in cross‐sectional area. There was a trivial transvenous pressure gradient. After ablation, there was a significant increase in both anterograde and retrograde flow velocities and pressure gradient, the magnitudes of which were inversely proportional to the preablation and postablation areas. Direct visualization of the ablation zone revealed circumferential wall swelling, reduced cross‐sectional area, and diminishment in phasic variation in cross‐sectional area. Similar observations were made at contiguous nonablated sites, diminishing in magnitude as a function of distance. Conclusion: Pulmonary vein ablation induces significant acute changes in morphology and mechanical function that extend beyond the ablation zone. (J Cardiovasc Electrophysiol, Vol. 15, pp. 161‐167, February 2004)
Catheter Ablation of Common‐Type Atrial Flutter Guided by Three‐Dimensional Right Atrial Geometry Reconstruction and Catheter Tracking Using Cutaneous Patches:
Authors: VENTURA RODOLFO , ROSTOCK THOMAS , KLEMM HANNO U. , LUTOMSKY BORIS , DEMIR CAGRI , WEISS CHRISTIAN , MEINERTZ THOMAS , WILLEMS STEPHAN 
Published: December 2004

Introduction: EnSite® NavX™ (NavX) is a novel mapping and navigation system that allows visualization of conventional catheters for diagnostic and ablative purposes and uses them to create a three‐dimensional (3D) geometry of the heart. NavX is particularly suitable for ablation procedures utilizing an anatomic approach, as in the setting of common‐type atrial flutter (AFL). The aim of this study was to compare NavX‐guided and conventional ablation procedures for AFL. Methods and Results: Forty consecutive patients (32 male, 59 ± 12 years) with documented AFL were randomized to undergo fluoroscopy‐guided (group I, 20 patients) or NavX‐guided (group II, 20 patients) ablation, including 3D isthmus reconstruction. The same catheter setup was used in both groups. The endpoint of bidirectional isthmus block was obtained in all patients. Compared to conventional approaches, NavX‐guided procedures significantly reduced fluoroscopy time (5.1 ± 1.4 min vs 20 ± 11 min, P < 0.01) and total x‐ray exposure (5.1 ± 3.1 Gycm2 vs 24.9 ± 1.6 Gycm2, P < 0.01). Isthmus geometry reconstruction could be performed in all patients of group II. In 4 patients (20%) of group II, anatomic isthmus variations were detected by NavX. No significant differences in radiofrequency current applications and procedural times were found between the two groups. Conclusion: NavX technology allows geometry reconstruction of the cavotricuspid isthmus. NavX‐guided ablation of AFL reduces total x‐ray exposure compared to the fluoroscopy‐guided approach but does not prolong procedure time.
Individual Patterns of Dynamic QT/RR Relationship in Survivors of Acute Myocardial Infarction and Their Relationship to Antiarrhythmic Efficacy of Amiodarone
Authors: SMETANA PETER , PUEYO ESTHER , HNATKOVA KATERINA , BATCHVAROV VELISLAV , LAGUNA PABLO , MALIK MAREK 
Published: December 2004

Introduction: Amiodarone is an effective antiarrhythmic drug, but it has serious side effects and conducted trials did not support its prophylactic use in survivors of acute myocardial infarction. It is possible that the prophylactic use of the drug has not been tested effectively. To optimize therapy outcome, markers of drug efficacy might be developed to identify patients who, although at arrhythmic risk, would not benefit from amiodarone treatment. We investigated descriptors of QT/RR relationship for their potential value in predicting inefficient amiodarone treatment. Methods and Results: The study used 866 Holter recordings (462 amiodarone, 404 placebo) obtained 1 month after randomization in the European Myocardial Infarct Amiodarone Trial (EMIAT). A commercial Holter system was used to measure RR and QT intervals. Subject‐specific descriptors of QT/RR relationship were calculated. Comparison was performed in amiodarone‐ and placebo‐treated patients, distinguishing patients who did and did not suffer from arrhythmic death. QT/RR relationship and individually corrected QTc interval differed significantly, not only between amiodarone‐ and placebo‐treated postmyocardial infarction patients but also between patients with and without arrhythmic death on amiodarone (QTc with vs without arrhythmic death 426.30 ± 33.93 ms vs 444.23 ± 36.65 ms, P = 6.5 × 10‐3). In a multivariate analysis, reduced optimum regression residuum (14.33 ± 7.08 vs 20.11 ± 9.39, P = 4.4 × 10‐3) and flatter slope (0.44 ± 0.19 vs 0.55 ± 0.24, P = 4.0 × 10‐2) of the QT/RR relationship independently predicted arrhythmic death during follow‐up. Conclusion: Chronic amiodarone treatment markedly affects the QT/RR relationship. The lack of treatment‐related QT/RR changes predicts arrhythmic death. Descriptors of complexity of QT/RR relation seem to be potent markers of treatment efficiency.
Pressure simulation of orthodontic force in osteoblasts: a pilot study
Authors: Baumert U. , Golan I. , Becker B. , Hrala B.P. , Redlich M. , Roos H.A. , Palmon A. , Reichenberg E. , Müßig D. 
Published: December 2004

Structured AbstractAuthors – Baumert U, Golan I, Becker B, Hrala BP, Redlich M, Roos HA, Reichenberg E, Palmon A, Müßig DObjectives – To elucidate the RUNX2 gene expression induction in human osteoblasts after mechanical loading.Design – Using a stringent pulse‐chase protocol human osteoblasts were exposed to centrifugal pressure force for 30 and 90 min. Untreated control cells were processed in parallel. Before, and at defined times after centrifugation, total RNA was isolated. RUNX2 gene expression was measured using real‐time quantitative reverse transcriptase polymerase chain reaction. The stress/control ratio was used to illustrate possible stimulatory or diminishing effects of force application.Results – Immediately after 30 min of force application the RUNX2 gene expression was induced by a factor of 1.7 ± 0.14 as compared with the negative control. This induction decreased rapidly and reached its pre‐load levels within 30 min. Longer force applications (up to 90 min) did not change the RUNX2 gene expression.Conclusion – In mature osteoblasts centrifugal pressure force stimulates RUNX2 gene expression within a narrow time frame: loading of mature cells results in a temporary increase of RUNX2 expression and a fast downregulation back to its pre‐load expression level. With this pilot study the gene expression behavior after mechanical stimuli could be determined with a simple laboratory setup.
Tobin Tax Effects Seen from the Foreign Exchange Market's Microstructure
Authors: Mende Alexander , Menkhoff Lukas 
Published: December 2004

AbstractThere are strong calls for the introduction of a ‘Tobin tax’ on foreign exchange (FX) transactions. Despite its popularity, research has not yet made full use of available insights from the recent microstructure literature. The role of banks in FX trading is quite different from the assumptions of proponents. Asset managers are most probably the group with the heaviest influence on shorter‐term exchange rate movements. They speculate under comparatively longer horizons than FX dealers, although their behaviour also tends to be short‐termist. We argue that there is no tax rate that could both influence their behaviour and simultaneously maintain the desired high level of liquidity. We conclude that no uniform proportional Tobin tax can achieve its objectives.
In search of local autonomy: the politics of big cities in Russia's transition
Authors: Gel'man Vladimir 
Published: December 2004

Despite a series of local government reforms in the 1990s, Russia's localities still lack serious autonomy. Only big cities maintain hopes for the emergence of local autonomy and local democracy. City politics has produced multiple conflicts between regional and local authorities; however, regional‐local relations merely reflect fundamental center‐periphery controversies on a smaller territorial scale. While big cities and their metropolitan areas serve as centers of political, economic and social modernization, other regional areas are lost in the peripheries. During Russia's transition period, some large cities acquired more political and economic autonomy from regions than others did. This article concentrates on the crucial role of (1) political opportunities inherited from the late‐Soviet period; and (2) strategic choices of political actors in the post‐Soviet period. The constellation of initial conditions and outcomes of political conflicts have contributed greatly to the diversity of city politics and urban autonomy in Russia's cities. Finally, the article considers the possible impact of local autonomy in Russia's cities on national social, economic and political developments.Malgré la série de réformes des années 1990 sur les gouvernements locaux en Russie, les localités manquent toujours d'une véritable autonomie. Seules, les grandes villes espèrent encore l'avènement d'une autonomie et d'une démocratie locales. La politique urbaine a généré nombre de conflits entre autorités locales et régionales; ceux‐ci ne sont pourtant que le reflet de la polémique fondamentale entre centre et périphérie à une échelle territoriale réduite. Alors que les grandes villes et leur métropole concentrent modernisations sociales, économiques et politiques, le reste de la région se fond dans les périphéries. Pendant la Russie de transition, quelques grandes villes ont acquis davantage d'autonomie économique et politique que d'autres par rapport à leur région. L'article détaille le rôle crucial qu'ont joué, d'une part, les ouvertures politiques héritées de la fin du régime précédent et, d'autre part, les choix stratégiques des acteurs politiques de l'ère post‐soviétique. La pléiade de conditions initiales et de séquelles de conflits politiques a largement contribuéà diversifier les politiques urbaines et le degré d'autonomie des villes russes. Enfin, l'article aborde l'impact éventuel d'une autonomie locale des villes sur les évolutions sociales, économiques et politiques de la Russie.
Comments on Jeff R. Crump's ‘The end of public housing as we know it: public housing policy, labor regulation and the US city’
Authors: Schwartz Alex 
Published: December 2004

Jeff Crump's discussion of housing policy in the United States is highly polemic but not very analytic or informative. Crump argues that federal housing policy is attempting to move people out of public housing and into the private housing market and the lowwage labor force. However, he fails to support his argument with credible evidence. My comments point out the most egregious of Crump's claims. I start with Crump's most extreme contentions that housing policy is coercing public housing residents into the low‐wage labor force. I then question his dismissive attitude toward the problems confronted by residents of distressed public housing and policies designed to help low‐income families move out of impoverished neighborhoods. I subsequently show how Crump exaggerates the extent to which federal housing policy is clearing central cities of subsidized low‐income housing. I conclude with a few words on the serious issues that a more informed critique of US housing policy could have raised.L'exposé de Jeff Crump sur la politique du logement aux Etats‐Unis relève principalement de la polémique, plus que de l'analyse ou de l'information. Selon lui, la politique fédérale tente de déplacer la population des logements sociaux vers les marchés de l'habitat privé et de la main‐d'œuvre à bas salaires. Toutefois, il n'apporte aucune preuve crédible à son propos. Ma réaction porte sur ses arguments les plus insignes, en commençant par ses allégations extrémistes selon lesquelles la politique du logement contraint les habitants des logements publics à des emplois peu rémunérés. Je remets ensuite en cause son dédain à l'égard des difficultés que rencontrent les résidents des logements sociaux insalubres, sans oublier les politiques prévues pour aider les familles à faibles revenus à quitter les quartiers pauvres. En conséquence, à mon avis, Crump exagère la mesure dans laquelle la politique fédérale élimine des centres‐villes les habitats à loyer modéré subventionnés. En quelques mots, ma conclusion porte sur les questions graves qu'aurait pu soulever un commentateur mieux documenté sur la politique du logement aux Etats‐Unis.