bluuebunny/crossref_metadata_2025_split huggingface dataset:
Association between clinically depressed subgroups, type of treatment and patient retention in the LIDO study
Authors: BECH P. , LUCAS R. , AMIR M. , BUSHNELL D. , MARTIN M. , BUESCHING D. ,   THE LIDO GROUP
Published: July 2004

Background. Few data are available with which to evaluate the association between depressed subgroups, type of treatment and patient retention during episodes of major depression.Method. This observational study followed 1117 depressed patients over a 12-month period in the primary care setting of six different international sites. The patients were divided into three severity-linked subgroups: moderate to severe depression; moderate depression co-morbid with serious medical conditions; and mild depression.Results. In general, a low dropout rate was found, with significant differences in the rates across the six sites. However, while there was no statistical significance in the association between the three subgroups of depression and overall dropout rates, we did find that older patients were less likely to drop out, more depressed patients were more likely to drop out, and if patients were on antidepressants they were less likely to drop out. Among the three subgroups of depression, patients with moderate depression co-morbid with serious medical conditions received the lowest amount of antidepressants and had the lowest quality of life.Conclusion. Although the overall dropout rate in this study was found very low and did differ between the six sites, an association between the use of antidepressants and patient retention was seen. The group of patients with serious co-morbid medical conditions received fewer antidepressants even when the level of their depressive states was taken into consideration. This group was the least satisfied with treatment and had the lowest self-reported quality of life.
Base invariance of the manipulability index
Authors: Gotlih Karl , Troch Inge 
Published: July 2004

The manipulability index suggested by Yoshikava is an important tool for the design of mechanisms and their control. It represents a quantitative measure of the functionality and the ability for realizing some tasks or groups of tasks. This index is some kind of performance measure and should be taken into consideration in the design phase of a mechanism and also in the design of control algorithms.In this paper two important properties of the manipulability index are investigated. The first part of the present work demonstrates that manipulability of a mechanism is independent of task space coordinates. In the second part, a proof of the independency of the manipulability index on the first DOF is given.This invariance is important for simplification of the mechanism's Jacobian matrix and gives excellent insight into the dependences of configuration space coordinates on this index. Moreover, it proves that the manipulability index is determined only by relative positions of the mechanism itself and by the mechanism's geometry.Finally, the properties of the manipulability index are illustrated by some examples for fundamental open kinematical chain structures.
Pulmonary Vein Isolation for Atrial Fibrillation in Patients with Symptomatic Sinus Bradycardia or Pauses
Authors: KHAYKIN YAARIV , MARROUCHE NASSIR F. , MARTIN DAVID O. , SALIBA WALID , SCHWEIKERT ROBERT , WEXMAN MARK , STRUNK BRIAN , BEHEIRY SALWA , SAAD EDUARDO , BHARGAVA MANDEEP , BURKHARDT J. DAVID , JOSEPH GEORGE , TCHOU PATRICK , NATALE ANDREA 
Published: July 2004

Introduction: Sick sinus syndrome is commonly associated with tachyarrhythmias and bradyarrhythmias that often are symptomatic. The aim of this study was to assess the effect of pulmonary vein isolation in patients with sick sinus syndrome and atrial fibrillation (AF). Methods and Results: Three hundred fourteen consecutive patients who underwent pulmonary vein isolation between December 2000 and January 2002 were included in the study. Thirty‐one patients had sick sinus syndrome, which was defined as a preprocedural history of symptomatic sinus bradycardia or pauses. Endpoints included AF recurrence, change in the frequency of sinus pauses, and symptoms of presyncope or syncope, as well as mean heart rate and percentage of atrial pacing in patients with pacemakers implanted prior to the pulmonary vein isolation. Patients had AF for an average of 6 ± 3 years. Patients were 58 ±8 years old and had ejection fractions of 55 ± 4%. Sixty‐one percent had implanted pacemakers. AF recurred within 6 months in 4 patients. Two had a successful second pulmonary vein isolation procedure. There were no recurrences of presyncopal events (P < 0.05) or documented sinus pauses (P < 0.05) after successful pulmonary vein isolation in the patients without permanent pacemakers. Patients with pacemakers had a 13‐fold reduction in the percentage of atrial pacing (P < 0.05). Both groups showed a significant increase in average heart rates at 6‐month follow‐up. Conclusion: Cure of AF by pulmonary vein isolation helped resolve the clinical manifestations of sick sinus syndrome, suggesting that the occurrence of AF and/or the associated treatment could be partially responsible for sick sinus syndrome. (J Cardiovasc Electrophysiol, Vol. 15, pp. 784‐789, July 2004)
Restoration of Heart Rate Turbulence by Titrated Beta‐Blocker Therapy in Patients with Advanced Congestive Heart Failure:
Authors: LIN LIAN‐YU , HWANG JUEY‐JEN , LAI LING‐PING , CHAN HSIAO‐LUNG , DU CHAO‐CHENG , TSENG YUNG‐ZU , LIN JIUNN‐LEE 
Published: July 2004

Introduction: Heart rate turbulence (HRT) is a powerful novel predictor for cardiovascular mortality. Chronic congestive heart failure is associated with abnormal HRT. Whether antiadrenergic beta‐blocker therapy can restore control of HRT in patients with chronic congestive heart failure is unknown. Methods and Results: A 24‐hour Holter ECG recording was obtained before and 1 and 3 months after titrated addition of atenolol therapy in 10 consecutive patients with advanced congestive heart failure. Two parameters derived from HRT, turbulence slope (TS) and turbulence onset (TO), and time‐ and frequency‐domain heart rate variability (HRV) parameters (SDNN, RMSSD, VLF, LF, HF) from 24‐hour ECG were compared before and after beta‐blocker therapy, together with the same parameters in age‐matched normal control. Results showed that TS (3.1 ± 2.2 vs 6.2 ± 3.0; P = 0.001) and all HRV parameters were increased after 3 months of atenolol treatment. No changes in TO were evident (0.6 ± 0.5 vs −0.2 ± 1.3; P = 0.13). The improvement of TS and the vagally mediated parameters of mean R‐R interval, RMSSD, and the HF component of HRV were positively correlated. Conclusion: Abnormal HRT caused by chronic congestive heart failure can be restored by beta‐blocker therapy. The evolution of TS was positively correlated with measures of vagal modulation of heart rate. (J Cardiovasc Electrophysiol, Vol. 15, pp. 752‐756, July 2004)
Electrophysiologic Characteristics of Atrial Tachycardia Originating from the Right Pulmonary Veins or Posterior Right Atrium:
Authors: YAMADA TAKUMI , MURAKAMI YOSHIMASA , MUTO MASAHIRO , OKADA TARO , OKAMOTO MITSUHIRO , TOYAMA JUNJI , YOSHIDA YUKIHIKO , TSUBOI NAOYA , ITO TERUO , KONDO TAKAHISA , INDEN YASUYA , HIRAI MAKOTO , MUROHARA TOYOAKI 
Published: July 2004

Introduction: The right pulmonary veins (RPVs) and posterior wall of the right atrium (PRA) are anatomically located adjacent to each other. The aim of this study was to demonstrate the electrophysiologic characteristics of atrial tachycardia (AT) originating from the PRA or RPVs. Methods and Results: A total of 26 consecutive patients with AT originating from the RPVs or PRA underwent detailed atrial endocardial mapping and successful radiofrequency catheter ablation. Eight foci were found in the PRA and 18 foci in the RPVs. Analysis of P wave configuration showed that lead V1 was the most helpful in distinguishing the AT foci between these two sites. In all cases, double potential (DP) configurations were recorded from several electrodes of a multielectrode catheter placed in the PRA, and the first DP component (FP) was the earliest potential recorded from the right atrium during the tachycardia. The amplitude of the FP was higher than that of the second DP component (SP) for AT foci originating in the PRA, whereas the reverse occurred for those in the RPV. The activation sequence of the FP was from superior to inferior for the AT foci in the superior RPV, whereas the reverse occurred for the AT foci in the inferior RPV. Conclusion: P wave configuration in lead V1 is helpful in distinguishing AT foci between those originating in the PRA and RPVs. The DPs obtained from the PRA can be useful in predicting whether AT foci originate from the PRA or RPVs. (J Cardiovasc Electrophysiol, Vol. 15, pp. 745‐751, July 2004)
Accuracy of Mode Switch Algorithms for Detection of Atrial Tachyarrhythmias
Authors: PASSMAN ROD S. , WEINBERG KENNETH M. , FREHER MARK , SCHAECHTER ANDI , GOLDBERGER JEFFREY J. , KADISH ALAN H. 
Published: July 2004

Introduction: In patients with permanent pacemakers, mode switching events often are interpreted as surrogate markers for atrial tachyarrhythmias. The aim of this study was to determine the accuracy of automatic mode switching algorithms in patients with permanent pacemakers for the diagnosis of atrial tachyarrhythmias. Methods and Results: Forty patients with tachycardia‐bradycardia syndrome and Medtronic Thera or Kappa 700 permanent pacemakers underwent Holter monitoring. Date, time of onset, and duration of each mode switch episode as recorded by the pacemaker and each atrial tachyarrhythmia episode as recorded by the Holter monitor were compared. Sixteen patients had a total of 54 atrial tachyarrhythmias documented on Holter monitoring (47 atrial fibrillation, 7 atrial flutter). Comparison of Holter data with pacemaker interrogation demonstrated that 53 (98.1%) of 54 atrial tachyarrhythmia episodes resulted in mode switching with one 13‐second episode of mode switching during sinus rhythm. The sensitivity and specificity of mode switching for the duration of atrial tachyarrhythmias were 98.1% and 100%, respectively. The algorithms detected 98.9% of the total duration of atrial fibrillation and 96.4% of the total duration of atrial flutter. Conclusion: In patients with tachycardia‐bradycardia syndrome and permanent pacemakers having these mode switching algorithms, mode switching events are reliable surrogate markers for atrial tachyarrhythmias. Therefore, mode switching may serve as a valuable tool for clinical decision making and further research into the natural history and burden of atrial tachyarrhythmias. (J Cardiovasc Electrophysiol, Vol. 15, pp. 773‐777, July 2004)
Transmural Action Potential Repolarization Heterogeneity Develops Postnatally in the Rabbit
Authors: IDRISS SALIM F. , WOLF PATRICK D. 
Published: July 2004

Introduction: In the hereditary long QT syndrome, arrhythmia risk changes with age despite the presence of an ion channel mutation throughout development. Age‐dependent changes in the transmural dispersion of repolarization may modulate this vulnerability. We recorded cardiac action potentials in infant, periadolescent, and adult rabbit myocardium to determine if transmural heterogeneities in repolarization are developmentally determined. Methods and Results: Arterially perfused ventricular preparations were studied from 2‐week (n = 7), 7‐week (n = 7), and adult (n = 6) NZW rabbits. Action potentials were recorded with microelectrodes in five regions: epicardium (epi), subepicardium (subepi), midwall (mid), subendocardium (subendo), and endocardium (endo) during endocardial S1 pacing at cycle lengths of 2,000, 1,000, and 500 ms. At 2 weeks, the transmural APD90 profile was flat. With age, APD prolongation from subepi to endo created a transmural repolarization gradient. At 7 weeks, APD90 was significantly longer at subendo [204 ± 2 ms (mean ± SE) 2,000‐ms cycle length, P < 0.05] vs both endo (193 ± 2 ms) and epi (172 ± 2 ms), causing a heterogeneous transmural APD90 gradient. In adults, the transmural gradient was a smooth continuum such that APD was shortest in epicardium and longest in endocardium. Conclusion: The transmural distribution of APD is developmentally determined. Tissue‐specific age‐dependent changes in APD can result in transmural repolarization heterogeneity. These age‐related effects may modulate arrhythmia vulnerability during development. (J Cardiovasc Electrophysiol, Vol. 15, pp. 795‐801, July 2004)
Electrophysiologic Effects of Nicorandil on the Guinea Pig Long QT1 Syndrome Model
Authors: YANG ZHIFANG , SHI GUOZHONG , LI CIZHENG , WANG HONGWEI , LIU KAI , LIU YUANMOU 
Published: July 2004

Introduction: The slow component of the delayed rectifier K+ current IKs modulates repolarization of the cardiac action potential (AP), and the loss of IKs is known to cause long QT1 (LQT1) syndrome by prolonging action potential duration (APD). In this study, we generated a guinea pig LQT1 syndrome model using the IKs blocker chromanol 293B and then assayed the electrophysiologic effects of the ATP‐sensitive potassium channel IK,ATP opener nicorandil on this model. Methods and Results: Transmembrane action potentials of perfused right ventricular papillary muscle preparations and both in vitro and in vivo ECGs of guinea pigs were recorded. Blockade of IKs by chromanol 293B (30 μM) prolonged the action potential duration at 90% repolarization (APD90) by 8.5% and QT interval by 16.5% of control values. In addition, proarrhythmic early afterdepolarizations (EADs) and ventricular fibrillation were observed. Venoinjection of chromanol 293B (1 mg/kg) revealed 10.9% QT prolongation. Nicorandil (5–30 μM) dose‐dependently shortened APD90 under the control condition, whereas it reversed the AP prolongation effect of chromanol 293B by 7.4% at the 30 μM concentration. Moreover, nicorandil shortened QT intervals both in vitro and in vivo and displayed an inhibitory effect on EADs and ventricular fibrillation. Conclusion: The ATP‐sensitive potassium channel opener nicorandil may be an effective drug in the therapy of LQT1 syndrome by shortening APD and the QT interval. (J Cardiovasc Electrophysiol, Vol. 15, pp. 815‐820, July 2004)
Prospective Assessment after Pediatric Cardiac Ablation:
Authors: VAN HARE GEORGE F. , JAVITZ HAROLD , CARMELLI DORIT , SAUL J. PHILIP , TANEL RONN E. , FISCHBACH PETER S. , KANTER RONALD J. , SCHAFFER MICHAEL , DUNNIGAN ANN , COLAN STEVEN , SERWER GERALD ,   Participating Members of the Pediatric Electrophysiology Society
Published: July 2004

Introduction: A multicenter prospective study was designed and implemented to assess the short‐ and longer‐term results and risks associated with radiofrequency (RF) ablation in children. Methods and Results: Patients recruited for the study were aged 0 to 16 years with supraventricular tachycardia due to accessory pathways or AV nodal reentrant tachycardia (AVNRT), excluding patients with nontrivial congenital heart disease. A national registry also was established, and contributing centers were encouraged to enroll all pediatric patients, aged 0 to 21 years, undergoing ablation at their center. This report summarizes acute results of these procedures. For analysis, subjects were divided into three groups: the prospective cohort (n = 481), cohort‐eligible registry participants (n = 504), and not cohort eligible registry participants (n = 1,776). Prospectively enrolled cohort patients were similar to cohort‐eligible patients in terms of demographic and other patient characteristics. Overall success rates for RF ablation were high (95.7%), with higher success rates for left‐sided and particularly left free‐wall pathways (97.8%) than right free‐wall pathways (90.8%). Complications of both electrophysiologic study and RF ablation were infrequent (4.2% and 4.0%, respectively), and there were no deaths. AV block was uncommon overall (1.2%) and was limited to ablation in AVNRT (2.1%) and septal accessory pathways (3.0%). Conclusion: Despite the multicenter and prospective design, the study demonstrates high success rates and low complication rates, which are comparable to prior single‐center retrospective studies. These results may serve as the current best benchmark for expected results in the pediatric population, aged 0 to 16 years, both in terms of acute success rates and the occurrence of complications. (J Cardiovasc Electrophysiol, Vol. 15, pp. 759‐770, July 2004)
Left Atrial Isthmus:
Authors: BECKER ANTON E. 
Published: July 2004

Introduction: The success rate of catheter maze ablation procedures for atrial fibrillation depends upon adequate electrical isolation by performing linear ablation lesions. However, recurrence of atrial arrhythmias is not uncommon, particularly in the so‐called left atrial isthmus, between the orifice of the left inferior pulmonary vein and the mitral valve annulus. The focus of the present study is the anatomy of this area. Methods and Results: Twenty human hearts were studied. The distance between the left inferior pulmonary vein and the mitral valve, the thickness of the left atrial myocardium, and the extent of left atrial myocardium toward the mitral valve were measured. The AV groove contained a fat pad harboring the great cardiac vein. The distance between the vein and the valve varied considerably (range 17–51 mm). The great cardiac vein coursed along the inferior left atrial wall, approximately 1 cm above the level of the mitral valve. Myocardial thickness also varied considerably (distal: range 1.4–7.7 mm, midway: range 1.2–4.4 mm, proximal: range 0−3.2 mm). Left atrial myocardium extended onto the mitral valve in two hearts, and the left atrial myocardium ended above the level of the mitral valve (range 1.8−5.1 mm) in six hearts. An important variable because it raises the question of how much energy should be used—and at which point—to achieve an adequate transmural ablation line. Conclusion: The great cardiac vein is not an adequate marker for the level of the mitral valve, left atrial myocardium may continue onto the mitral valve, the distance between the left inferior pulmonary vein and mitral valve varies considerably, and left atrial myocardial thickness is highly variable and not uniform.(J Cardiovasc Electrophysiol, Vol. 15, pp. 809‐812, July 2004)
Effect of Rapid Biphasic Shock Subpulse Switching on Ventricular Defibrillation Thresholds
Authors: DOSDALL DEREK J. , ROTHE DARRIN E. , BRANDON TEDD A. , SWEENEY JAMES D. 
Published: July 2004

Introduction:The aim of this study was to demonstrate that significant reductions in defibrillation threshold (DFT) can be achieved by rapidly switching defibrillation pulses within an overall biphasic envelope between multiple endovascular electrode sets.Methods and Results:Defibrillation electrodes were implanted in four locations in nine anesthetized swine (41.7 ± 8.7 kg). Electrodes were implanted into the right ventricular apex (RV), the superior vena cava (SVC), over the left pectoral region as a “hot can” (Can), and within the middle cardiac vein on the posterior left ventricular (LV) surface. The 50% DFT (level for which 50% of delivered shocks successfully defibrillated) for control shocks (7‐ms first phase, 0.5‐ms interpulse period, 4‐ms second phase, RV−→ SVC++ Can+) were determined to have energy of 20.5 ± 5.5 J (mean ± SD). Mean 50% DFTs were also determined for waveforms that split each phase of the same overall biphasic waveform between various electrode sets. Each phase was divided into 2, 3, 4, or 6 subpulses, the defibrillation shock was sequentially delivered to multiple electrode sets, and DFTs were determined (11.9 ± 4.8 J, 11.7 ± 2.9 J, 17.9 ± 8.7 J, 16.7 ± 6.1 J, respectively). DFT energy was statistically lower than the control (Wilcoxon sign rank test; P < 0.05) when each phase was divided into 2 or 3 subpulses.Conclusion:Rapid shock switching within an overall biphasic waveform between electrode sets including an electrode in the middle cardiac vein potentially can lower DFT energy by 40% or more.(J Cardiovasc Electrophysiol, Vol. 15, pp. 802‐808, July 2004)
Quantitative DNA methylation analysis based on four-dye trace data from direct sequencing of PCR amplificates
Authors: Lewin Jörn , Schmitt Armin O. , Adorján Péter , Hildmann Thomas , Piepenbrock Christian 
Published: July 2004

Abstract
Motivation: Methylation of cytosines in DNA plays an important role in the regulation of gene expression, and the analysis of methylation patterns is fundamental for the understanding of cell differentiation, aging processes, diseases and cancer development. Such analysis has been limited, because technologies for detailed and efficient high-throughput studies have not been available. We have developed a novel quantitative methylation analysis algorithm and workflow based on direct DNA sequencing of PCR products from bisulfite-treated DNA with high-throughput sequencing machines. This technology is a prerequisite for success of the Human Epigenome Project, the first large genome-wide sequencing study for DNA methylation in many different tissues. Methylation in tissue samples which are compositions of different cells is a quantitative information represented by cytosine/thymine proportions after bisulfite conversion of unmethylated cytosines to uracil and PCR. Calculation of quantitative methylation information from base proportions represented by different dye signals in four-dye sequencing trace files needs a specific algorithm handling imbalanced and overscaled signals, incomplete conversion, quality problems and basecaller artifacts.
Results: The algorithm we developed has several key properties: it analyzes trace files from PCR products of bisulfite-treated DNA sequenced directly on ABI machines; it yields quantitative methylation measurements for individual cytosine positions after alignment with genomic reference sequences, signal normalization and estimation of effectiveness of bisulfite treatment; it works in a fully automated pipeline including data quality monitoring; it is efficient and avoids the usual cost of multiple sequencing runs on subclones to estimate DNA methylation. The power of our new algorithm is demonstrated with data from two test systems based on mixtures with known base compositions and defined methylation. In addition, the applicability is proven by identifying CpGs that are differentially methylated in real tissue samples.