bluuebunny/crossref_metadata_2025 huggingface dataset:
Grape seed extract reduces oxidative stress and fibrosis in experimental biliary obstruction
Authors: Dulundu Ender , Ozel Yahya , Topaloglu Umit , Toklu Hale , Ercan Feriha , Gedik Nursal , Şener Goksel
Published: April 2007

Background and Aim:  The aim of this study was to assess the protective effect of grape seed extract (GSE) against oxidative liver injury and fibrosis induced by biliary obstruction in rats.

Methods:  Wistar albino rats were divided into four groups; control (C), GSE‐treated, bile duct ligated (BDL), and BDL and GSE‐treated (BDL + GSE) groups. GSE was administered at a dose of 50 mg/kg a day orally for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver function and tissue damage, respectively. Tumor necrosis factor‐alpha (TNF‐α) and antioxidant capacity (AOC) were assayed in plasma samples. Liver tissues were taken for determination of the hepatic malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Production of reactive oxidants was monitored by chemiluminescence (CL) assay.

Results:  Serum AST, ALT, LDH and plasma TNF‐α were elevated in the BDL group as compared to the control group and were significantly decreased with GSE treatment. Plasma AOC and hepatic GSH level, depressed by BDL, was elevated back to the control level in the GSE‐treated BDL group. Increases in tissue MDA level, MPO activity and collagen content due to BDL were also attenuated by GSE treatment. Furthermore, luminol and lucigenin CL values in the BDL group increased dramatically compared to the control and were reduced by GSE treatment.

Discussion:  These results suggest that GSE protects the liver from oxidative damage following bile duct ligation in rats. This effect possibly involves the inhibition of neutrophil infiltration and lipid peroxidation; thus, restoration of oxidant and antioxidant status in the tissue.
Evolutive phases of experimental prehepatic portal hypertension
Authors: Aller Maria‐Angeles , Nava Maria‐Paz , Cuellar Carmen , Chivato Tomas , Arias Jorge‐Luis , Sanchez‐Patan Fernando , De Vicente Felipe , Alvarez Emilio , Arias Jaime
Published: April 2007

Partial portal vein ligation is the experimental model most frequently used to study prehepatic portal hypertension. Different systemic and splanchnic biochemical and histological alterations in short‐term (28–45 days) and long‐term (12–14 months) evolutive phases which has been described in this experimental model suggest the existence of different pathophysiological mechanisms involved in their production. The enteropathy produced could develop in three phases: an early or acute phase with vasomotor hemodynamic alterations (ischemia‐reperfusion associated with intestinal hyperemia, edema and oxidative stress); an intermediate phase with immunological alterations (mesenteric lymphadenopathy, increased mucosal infiltration by mast cells and the hepato‐intestinal release of pro‐ and anti‐inflammatory mediators); and a late or chronic phase with intestinal remodeling (vascular and epithelial). The alterations which are produced in these three evolutive phases make it possible to propose an inflammatory etiopathogeny for hypertensive portal enteropathy.
Oxidative stress and metabolism in animal model of colitis induced by dextran sulfate sodium
Authors: Damiani Carlos R , Benetton César A F , Stoffel Cristhopher , Bardini Katrine C , Cardoso Vilson H , Di Giunta Gabriela , Pinho Ricardo A , Dal‐Pizzol Felipe , Streck Emilio L
Published: April 2007

Background and Aim:  Ulcerative colitis is a chronic inflammatory disease of the gastrointestinal tract. Its etiology remains unclear, but it appears to result from a dysregulated immune response, with infiltration of phagocytic leukocytes into the mucosal interstitium. The production and release of reactive oxygen species by immune cells seems to play a crucial role in physiopathology of colitis. The aim of this work was to evaluate the effects of N‐acetylcysteine (NAC) and deferoxamine (DFX) in the treatment of colitis induced by dextran sulfate sodium (DSS).

Methods:  The effects of NAC and DRX on rats with DSS‐induced colitis were determined by measuring intestinal parameters of oxidative stress and mitochondrial function, inflammatory response and bowel histopathological alterations.

Results:  DSS increased white blood cells count and NAC and DFX did not prevent this effect. However, DSS increased mitochondrial respiratory chain complex IV in colon of rats and NAC and DFX prevented this alteration. In addition, thiobarbituric acid reactive substances were increased in colon of DSS‐treated rats. NAC and DFX, when taken together, prevented this effect. Complex II and succinate dehydrogenase were not affected by DSS, as protein carbonyl content.

Conclusions:  It is speculated that NAC and DFX might be useful for treatment of colitis, but further research is necessary to clarify these effects.
Surgical strategies and predictors of outcome for malignant neuroendocrine tumors of the pancreas
Authors: Bahra Marcus , Jacob Dietmar , Pascher Andreas , Plockinger Ursula , Kristiansen Glen , Neuhaus Peter , Langrehr Jan M
Published: April 2007

Background and Aim:  Neuroendocrine pancreatic carcinomas are rare and little information on factors influencing the clinical course and prognosis is presently available. The aim of this study was to retrospectively review all patients who underwent pancreatic resection for malignant neuroendocrine tumor of the pancreas at the one department from 1989 to 2003.

Methods:  Eleven male and eight female patients with a mean age of 51 years (range 13–76 years) underwent surgery for malignant neuroendocrine tumor of the pancreas. The prognostic relevance for long‐term survival was investigated for intrapancreatic localization of the primary, histological classification including proliferation index (Ki67), lymph node involvement, surgical treatment and long‐term survival after resection. The clinical course after resection was also evaluated. Statistical analysis was performed using multivariate analysis and Kaplan–Meier method.

Results:  Functional or non‐functional tumors occurred in six (32%) and 13 (68%) patients, respectively. The tumors were located in the pancreatic head in 10 patients (53%), body in three (15%) and tail in two (11%). Multilocular tumors were found in five (26%). Surgical procedures performed were six pylorus preserving pancreaticoduodenectomies (32%), four standard pancreaticoduodenectomies (21%), four distal pancreatectomies (21%), three total pancreatectomies (15%) and two segmental resections (11%). Multivariate analysis showed sex (P = 0.018), Ki67 proliferation index (P = 0.023), tumor diameter (P = 0.02) and tumor site (P = 0.011) as significant predictors of outcome.

Conclusion:  Malignant neuroendocrine tumors of the pancreas are associated with poor prognosis. Surgical resection is an appropriate and safe procedure with low morbidity rates. The prognosis seems to be determined by various biological factors. However, with regard to the principles of surgical oncology, tumor‐free resection margins are important and radical surgical procedures are justified in selected patients.
‘Blowing 'cross the crest of Mount Galeng’: winds of the voice, winds of the spirits
Authors: Roseman Marina
Published: April 2007

An enclave of animists in a predominantly Muslim nation, Temiars of peninsular Malaysia forge ingenious techniques to convert the commodities, concepts, and technologies that assault them towards their own religious and ideological uses. These aboriginal forest‐dwellers, a Senoi or Orang Asli people known in the anthropological and psychological literature for their techniques of dreaming, use songs received in dreams for healing purposes. Temiars are Austroasiatic‐speakers in a now Malay‐dominant nation. Battling colonial and neo‐colonial pressures in the Malay postcolony and the global economy, the members of this small‐scale society take refuge in montane forests, yet they have long interacted with Malays, British colonists, Chinese and Tamils brought to work in British mines and plantations, and communist guerillas in the aftermath of the Second World War. The key element in their survival is a technique economically combining music, medicine, and culture. This medico‐acoustic armature crafts the winds of breath, life, and voice into song. I explore how Temiars call on spirits through song, dance, and ceremony to address both individual and social wounds, as they craft their dances of healing and survival across the proverbial winds of history. Comparative materials on music, medicine, healing, and the environment from Africa, Europe, and elsewhere are examined.
An ill wind: the Foehn in Leukerbad and beyond
Authors: Strauss Sarah
Published: April 2007

The Foehn is a warm, dry, downslope wind found on the lee side of mountains; the type‐location for this adiabatic wind is the European Alps. In the Swiss village of Leukerbad, residents are quite familiar with the Foehn, which sweeps regularly through the main Rhone valley from the southeast. Leukerbad, located in a side valley, rarely experiences the full force of the Foehn, but the effects of this wind are well known: people say that the Foehn brings headaches, makes them depressed, invites suicide, and generates a feeling of ill health. In contrast, another wind occurring in this valley, the Gemmiwind – which comes over the Gemmi pass into Leukerbad from the north – is known only as a cold wind. Drawing on ethnographic data and literary representations as well as biomedical and meteorological analyses, we consider the meanings of the Foehn as it has penetrated the bodies and minds of mountain inhabitants in Switzerland and beyond.
Combining Police Perceptions with Police Records of Serious Crime Areas: A Modelling Approach
Authors: Haining Robert , Law Jane
Published: April 2007

The paper investigates the location of serious crime neighbourhoods in Sheffield, England, in 1998 on the basis of two sources of data: senior police officer perceptions of where such neighbourhoods are and the evidence that is contained in the police's own database of recorded crime. We report the results of modelling these two spatial distributions by using 2001 census data on output areas. We also demonstrate how expert knowledge might be combined with the evidence that is contained in large georeferenced databases. We conclude with an evaluation of the use of model-based approaches to identifying high crime areas. The purpose of the paper is to go beyond descriptive mapping of crime data and to explore how to combine, in a formal way, different types of knowledge in the analysis of crime and disorder maps.
Who Captures the Marks for the Petersen Estimator?
Authors: Goudie I. B. J. , Goudie M.
Published: April 2007

We examine the claim that the well-known Petersen estimator which is used in population size estimation was not in fact used by the scientist after whom it is named. We show how, in the early years of the last century, the modern use of the Petersen estimator grew from that of the fishing coefficient. Contending with the somewhat conflicting claims that were made at the time, and what by modern standards is poor referencing of sources, we investigate where the credit lies for these concepts, and the principles and protocols which support them. We assess also how far attributions of credit were affected by practical considerations, and the history of the estimator by the nature of the problems being pursued. We identify scientists whose early work on marking and estimating fish populations deserves more credit than it has received.
Estimating the Impact of the Specialist Schools Programme on Secondary School Examination Results in England*
Authors: Taylor Jim
Published: April 2007

This paper investigates the impact of the specialist schools programme in England on examination performance at age 16. Two approaches are used. The first uses pupil‐level data from the 2003 National Pupil Database. The second uses panel data methods and is based on time‐series data for secondary schools during 1992–2003. The paper also investigates the distributional consequences of the specialist schools programme. Specialist schools perform marginally better than their non‐specialist counterparts (especially in science, business studies and technology) but by much less than is indicated by previous studies. The programme does not appear to have had adverse distributional consequences.
Has the EU's Single Market Programme Fostered Competition? Testing for a Decrease in Mark‐up Ratios in EU Industries*
Authors: Badinger Harald
Published: April 2007

We use a panel approach, covering 10 EU Member States over the period 1981–99, for each of three major industry groups (manufacturing, construction and services) and 18 more detailed industries to test whether the EU's Single Market Programme has led to a reduction in firms’ mark‐ups over marginal costs. We address explicitly the uncertainty with respect to the timing of the changeover and allow for a possibly continuous regime shift in a smooth transition analysis. Where regime shifts can be found, the velocity of transition is extremely high, making the linear model a justifiable approximation. We also test for discrete structural breaks in the time window from 1986 to 1996, taking up endogeneity concerns in a generalized method of moments framework. Mark‐up reductions are found for aggregate manufacturing (although it is also suggested that mark‐ups increased in some manufacturing industries in the precompletion period at the end of the 1980s) and also for construction. In contrast, mark‐ups have gone up in most service industries since the early 1990s, which confirms the weak state of the Single Market for services and suggests that anti‐competitive defence strategies have emerged in EU service industries.
Safety of meloxicam to critically endangered Gyps vultures and other scavenging birds in India
Authors: Swarup D. , Patra R. C. , Prakash V. , Cuthbert R. , Das D. , Avari P. , Pain D. J. , Green R. E. , Sharma A. K. , Saini M. , Das D. , Taggart M.
Published: April 2007

Widespread veterinary use of the non‐steroidal anti‐inflammatory drug diclofenac is responsible for the population collapse of three species of Gyps vulture in south Asia; these species are now critically endangered. Vultures die when they consume carcasses of livestock that contain lethal residues of diclofenac. National and international conservation organizations have urgently recommended that diclofenac be banned and replaced with alternative drugs that are relatively safe to Gyps vultures and other scavenging birds. We tested the safety of the NSAID meloxicam on the oriental white‐backed vulture, long‐billed vulture and a range of other scavenging birds in India (Egyptian vulture Neophron percnopterus, cattle egret Bubulcus ibis, house crow Corvus splendens, large‐billed crow Corvus machrorhynchos and common mynah Acridotheres tristis). Meloxicam was administered by oral intubation [at 0.5 and 2.0 mg kg−1 vulture body weight (bw)], or through feeding with muscle or liver tissue (at 0.3 to 2.1 mg kg−1 vulture bw) from meloxicam‐treated buffalo Bubalus bubalis. We estimate that 2.0 mg kg−1 bw is the maximum likely exposure in the wild. All 31 Gyps vultures and the 20 other scavenging birds given meloxicam survived. Feeding behaviour remained normal and there were no significant differences between the treated and control groups in body mass, or the blood haematology and biochemistry parameters monitored, including those known to be affected by diclofenac (uric acid levels and alanine transferase activity). Meloxicam is used to treat a wide range of livestock ailments and is licensed and manufactured in India. We recommend that meloxicam be introduced as rapidly as possible across the Indian sub‐continent as an alternative to diclofenac.
Conservation genetics of the imperilled Barbary red deer in Tunisia
Authors: Hajji G. M. , Zachos F. E. , Charfi‐Cheikrouha F. , Hartl G. B.
Published: April 2007

Barbary red deer Cervus elaphus barbarus from three areas in Tunisia (n=30) were analysed for genetic variability at 13 microsatellite loci and 680 bp of the mitochondrial control region. Barbary red deer, the only African deer taxon, are presently confined to a small area along the Tunisian–Algerian border and underwent a severe bottleneck in the middle of the 20th century with, on the Tunisian side, possibly only seven animals left. The genetic data showed signs of inbreeding and reflected the bottleneck event. Variability was on the lower end of the range previously reported for red deer (number of haplotypes=two, observed and expected heterozygosity 0.46 and 0.78, respectively) but not as low as might have been feared in view of the population's demographic history. The three sampling sites – among them the reserve at El Feidja from which, apart from Algerian immigrants, all extant Tunisian red deer originate – did not show any sign of genetic differentiation. The Tunisian red deer can thus probably be considered a single, genetically homogeneous population. Implications for management and conservation of the genetic findings are discussed.
Thoracotomy Elevates the Defibrillation Threshold and Modifies the Defibrillation Dose‐Response Curve
Authors: FRIEDMAN PAUL A. , STANTON MARSHALL S.
Published: April 2007

Thoracotomy Elevates the Defibrillation Threshold. Introduction: Despite innovations in nonthoracotomy defibrillation systems, thoracotomies are still required in some clinical settings and are utilized in many animal‐based research protocols. The effect of a thoracotomy on defibrillation energy, however, has not been well characterized.

Methods and Results: Ten dogs in the immediate testing; group underwent defibrillation testing immediately following a thoracotomy: another ten dogs in the delayed testing group were given 48 to 72 hours of recovery before defibrillation testing. A right ventricular endocardial coil to cutaneous thoracic patch biphasic system was used. At the time of defibrillation testing, the immediate testing group had a faster mean heart rate (144.7 ± 30.2 vs 105.8 ± 17.5 beats/min, P < 0.01), higher mean pulmonary artery pressures (systolic: 18.14 ± 9.48 vs 11.28 ± 6.46 mmHg. P = 0.1; diastolic: 6.59 ± 2.88 vs 3.89 ± 1.75 mmHg, P <0.051, and higher mean defibrillation shock impedance (89.0 ± 11.6 vs 70.9 ± 7.3 ω, P < 0.002) than the delayed group. The mean ED50 (energy with a 50% success rate) was significantly higher in the immediate group than in the delayed group (26.9 ± 14.9 vs 14.2 ± 6.9 J, P < 0.05), and the slopes of the dose‐response curves were significantly different (P = 0.03).

Conclusion: In a right ventricular endocardial to cutaneous patch system, thoracotomy significantly and transiently increased the defibrillation threshold and modified the defibrillation dose‐response curve.
An Animal Model of Spontaneous Arrhythmic Death
Authors: MOÏSE N. SYDNEY , GILMOUR ROBERT E. , RICCIO MARK L.
Published: April 2007

Spontaneous Arrhythmic Death. Ventricular arrhythmias and the proclivity for sudden death have been identified in German shepherd dogs. This disorder is inherited, and affected animals can he consistently produced from an established colony. The arrhythmias are most prevalent in young dogs between 22 and 26 weeks of age, with death most frequent at this same age. Death occurs most frequently during presumed sleep or at rest after exercise or excitement. The QT interval is not prolonged; however, more frequent notching of the T wave exists in affected dogs compared to control dogs. Polymorphic rapid nonsustained ventricular tachycardia occurs most frequently following long RR intervals. Accordingly, perturhations that decrease the heart rate or enhance sinus arrhythmia increase the incidence of ventricular arrhythmias. Because the arrhythmias are age, behavior, and heart rate dependent, the autonomic nervous system may play a role in their generation. As determined by metaiodohenzylguanidine scintigraphy and immunocytochemical staining of tyrosine hydroxylase, cardiac sympathetic innervation is regionally deficient in affected dogs. Evidence suggests that initiation of the ventricular arrhythmias is caused by early after depolarization (EAD)‐induced triggered activity originating from left ventricular Purkinje fibers. Alpha1‐adrenergic stimulation provokes EADs in the Purkinje fibers and ventricular arrhythmias in the dogs. The development of EADs may be related to heterogeneity of repolarizing currents (Ito in particular) in affected dogs. From this canine model of spontaneous ventricular arrhythmias, the opportunity exists to investigate the interplay between abnormal development of cardiac innervation and the genesis of lethal ventricular arrhythmias.
Long‐Term Follow‐Up of Corridor Operation for Lone Atrial Fibrillation:
Authors: van HEMEL NORBERT M. , DEFAUW JO J.A.M. , GUIRAUDON GÉRARD M. , KELDER JOHANNES C. , JESSURUN EMILE R. , ERNST JEF M.P.G.
Published: April 2007

Late Results of Surgery for AF. Introduction: Currently, surgery‐ and catheter‐mediated ablation is applied when drug refractoriness of atrial fibrillation is evident, although little is known about the long‐term incidence of new atrial arrhythmia and the preservation of sinus node function.

Methods and Results: To address this issue, 30 patients with successful corridor surgery for lone paroxysmal atrial fibrillation and normal preoperative sinus node function were followed in a single outpatient department. Five years after surgery, the actuarial proportion of patients with recurrence of atrial fibrillation arising in the corridor was 8%± 5%, with new atrial arrhythmias consisting of atrial flutter and atrial tachycardia in the corridor 27%± 8%, and with incompetent sinus node requiring pacing therapy 13%± 6%. Right atrial transport was preserved in 69% of the patients without recurrence of atrial fibrillation and normal sinus node function. Stroke was documented in two patients.

Conclusions: Corridor surgery for atrial fibrillation is a transient or palliative treatment instead of a definitive therapy for drug refractory atrial fibrillation. This observation strongly affects patient selection for this intervention and constitutes a word of caution for other, non‐pharmacologic interventions for drug refractory atrial fibrillation.
Accuracy of the Unipolar Electrogram for Identification of the Site of Origin of Ventricular Activation
Authors: MAN K. CHING , DAOUD EMILE G. , KNIGHT BRADLEY P. , BAHU MARWAN , WEISS RAUL , ZIVIN ADAM , SOUZA S. JOSEPH , GOYAL RAJIVA , STRICKBERGER S. ADAM , MORADY ERED
Published: April 2007

Unipolar Electrogram. Introduction: The purpose of this study was to determine the accuracy of the unipolar electrogram for identifying the earliest site of ventricular activation. The earliest site of ventricular activation may be identified with the unipolar electrogram by the absence of an R wave. However, the accuracy of this technique is unknown.

Methods and Results: A single ventricular premature complex was induced mechanically at the tip of an electrode catheter to simulate a ventricular premature depolarization site of origin. Unipolar electrograms were recorded from the right ventricular septum at the tip electrode and at 2, 5, 8, and 11 mm from the electrode tip in 20 patients. No R waves were detected at the ventricular premature depolarization site of origin. R waves were detected in 4 of 20 patients (20%) at 2 mm from the tip electrode and 7 of 20 patients (35%) at 5, 8, and 11 mm from the tip electrode. An R wave was not observed at distances ≤ 11 mm from the site of tachycardia origin in 13 of 20 patients (65%).

Conclusions: While an R wave in the unipolar electrogram can he seen as close as 2 mm from the site of impulse origin, the absence of an R wave as an indicator of the site of impulse origin in the right ventricle is highly inaccurate. Therefore, the absence of an R wave in the unipolar electrogram is unlikely to be an adequate guide for identification of an effective target site for ablation of right ventricular tachycardia.
Epicardial Maps of Atrial Fibrillation After Linear Ablation Lesions
Authors: SIH HARIS J. , BERBARI EDWARD J. , ZIPES DOUGLAS R
Published: April 2007

Maps of AF After Ablation. Introduction: The purpose of this study was to investigate the mechanisms by which atrial linear ablation lesions eliminate atrial fibrillation (AF).

Methods and Results: With an array of 112 unipole, epicordial maps of electrically induced AF in 6 dogs (acute group), self‐sustained AF in 6 dogs (chronic group), and sinus rhythm and atrial pacing in 3 dogs (control group) were analyzed before and after creating linear radiofrequency ablation lesions in both atria that eliminated the AF. In the acute and chronic groups, activation maps showed multiple wavelets with complex patterns of activation and reentry during AF. Conduction velocity and the number, size, and complexity of wavelets did not change, whereas median fibrillatory cycle length increased with the number of linear lesions. In the control group, refractoriness and conduction velocity were unaffected by the number of lesions.

Conclusions: In these models of AF, linear lesions that eliminate AF increase the cycle length of AF without changing conduction velocity, number or size of wavelets, or complexity of activation patterns.
Reproducible Induction of “Atypical” Torsades de Pointes by Programmed Electrical Stimulation:
Authors: KRISHNAN SUBRAMANIAM C , MRCPI JOSEPH GALVIN. , McGOVERN BRIAN , GARAN HASAN , RUSKIN JEREMY N.
Published: April 2007

Sotalol‐Induced Polymorphic VT. We present a patient with sotalol‐induced polymorphic ventricular tachycardia that was seen only with programmed ventricular stimulation. Electrophysiologic studies performed prior to initiation of sotalol therapy revealed inducible monomorphic ventricular tachycardia. Possible underlying electrophysiologic mechanisms are discussed.
Protrusion Without Fracture of the Accufix Atrial “J” Lead Retention Wire
Authors: MERA FERNANDO , WALTER PAUL , LANGBERG JONATHAN
Published: April 2007

Retention Wire Fracture. The Telectronics Accufix atrial “J” lead has been associated with injury and death. These complications have occurred as the result of retention wire fracture, extrusion, und perforation of cardiac or vascular structures. This report describes a patient who was found to have protrusion of the proximal end of a nonfractured retention wire during: fluoroscopic surveillance. The wire extrusion appeared to result from angulation of the lead. The lead was extracted and replaced without adverse consequences. Further prospective analysis will be needed to determine the clinical implications and approach to this complication.
Effect of Electrode Polarity on Internal Defibrillation with Monophasic and Biphasic Waveforms Using an Endocardial Lead System
Authors: HUANG JIAN , KENKNIGHT BRUCE H. , WALCOTT GREGORY P. , WALKER ROBERT G. , SMITH WILLIAM M. , IDEKER RAYMOND E.
Published: April 2007

Defibrillation Electrode Polarity. introduction: To test the hypothesis that the effect of shock polarity on defibrillation depends on waveform duration, this study determined strength‐duration defibrillation curves of monophasic and biphasic truncated exponential waveforms for both polarities.

Methods and Results: Defibrillation thresholds (DFTs) were obtained in 32 pigs for catheter electrodes in the right ventricle (RV) and superior vena cava (SVC) using a modified Purdue technique. Both electrode polarities were tested in five different protocols. In part 1, DFTs were determined with 1‐ to 14‐msec monophasic waveforms. In parts 2, 3, and 4, DFTs were determined with two different sizes of SVC electrodes for biphasic waveforms with a phase 1 of 4 or 6 msec and a phase 2 ranging from 1 to 10 msec. In part 5, DFTs were tested for monophasic waveforms ranging from 2 to 11 msec and for biphasic waveforms with a phase 1 duration corresponding to each monophasic waveform and a phase 2 held constant at 1 msec. Mean DFTs for monophasic waveforms were significantly lower when the RV electrode was an anode than when it was a cathode for waveform durations ≥ 3 msec. For biphasic waveforms in which phase 2 was ≤ phase 1 in duration, no significant difference in mean DFT was observed when polarity was reversed. Even a phase 2 as short as 1 msec could eliminate the DFT difference between polarities observed with monophasic shocks. When phase 2 was ≥ 2 msec longer than phase 1, polarity did affect the DFT of biphasic waveforms: it affected the DFT similarly to a monophasic waveform of the same polarity as phase 2. Phase 1 duration and electrode size also affected the difference in DFT produced by changing the electrode polarity.

Conclusions: For phase durations most commonly used clinically because of their low DFTs. reversing polarity changed defibrillation efficacy for monophasic but not biphasic shocks. For inefficient biphasic waveforms with phase 2 ≥ 2 msec longer than phase 1, the DFT was lower when the RV electrode was an anode during phase 2, similar to the polarity difference for monopbasic waveforms, suggesting that a long second phase of biphasic waveforms defibrillates in a similar fashion to monophasic waveforms.
Recognizing and Managing Permanent Junctional Reciprocating Tachycardia in the Catheter Ablation Era
Authors: CRITELLI GIUSEPPE
Published: April 2007

Permanent Junctional Reciprocating Tachycardia. There is general agreement that an orthodromic AV reentry using a concealed slow conducting accessory pathway as the retrograde limb of the circuit constitutes the underlying mechanism of the permanent form of junctional reciprocating tachycardia (PJRT). In this arrhythmia, the standard ECG typically shows a “long R‐P’ tachycardia” with retrograde P waves negative in the inferior leads. A careful electrophysiologic evaluation is necessary to confirm the diagnosis of PJRT. Recent re ports have demonstrated that the radiofrequency current catheter technique provides a safe and highly effective therapeutic tool for patients suffering from this arrhythmia.
Electrophysiologic Properties of the Adult Human Sinus Node
Authors: DROUIN EMMANUEL
Published: April 2007

Electrophysiology of the Human SA Node. Electrophysiologic properties of the sinoatrial (SA) node have been studied extensively in various species. Published studies on human SA nodal properties were carried out on fetal SA node preparations; however, the electrophysiologic properties of adult human cardiac tissues have never been examined. In this study we report, for the first time, recordings of transmembrane potentials in the adult human SA node. Our data demonstrate that the electrical behavior of adult human SA node pacemaker cells resemble those of SA nodal tissue of different animal species. We conclude that the latter ideally mimic the former. Furthermore, human SA node preparations could contribute to a better understanding of some sinus arrhythmias.
Automated Ventricular Tachyarrhythmia Recognition
Authors: IGEL DAVID A. , WILKOFK BRUCE L.
Published: April 2007

Automated Ventricular Tachyarrhythmia Recognition.Introduction: Cardiac monitoring devices such as external cardioverter defibrillators and ICU computerized ECG monitoring systems sense individual QRS complexes to detect and subclassify ventricular tachyarrhythmias. Many algorithms that evaluate ECG morphology mark individual QKS complexes so that specific waveform characteristics can he measured. QRS sensors miss a percentage of electrogram events, especially during fibrillatory rhythms; thus, a morphology algorithm that helps subclassify arrhythmias without marking individual electrogram events may be more robust and improve arrhythmia detection accuracy.

Methods and Results: Four nonlinear dynamics calculations were evaluated for detecting ventricular tachyarrhythmias and for subclassifying monomorphic ventricular tachycardia (MVT) and polymorphic ventricular tachycardia (PVT). Five‐second epochs of normal (NML, n = 48), MVT (n = 58), and PVT (n = 75) rhythms were presented to a statistical discriminant function based on cycle length (CL), and its performance was compared to two other discriminant functions, one consisting of the nonlinear dynamics calculations and one consisting of a combination of all variables. The discriminant function based on nonlinear dynamics calculations and CL detected 100% of the ventricular tachyarrhythmias, and subclassified more (P < 0.001) MVT and PVT arrhythmias (90%) than that based on CL alone (71%).

Conclusions: The nonlinear dynamics measurements used in this study significantly increased the suhclassification accuracy of the CL‐based discriminant function, and they were calculated from ECG signals without marking individual QRS complexes. Therefore, arrhythmia detectors that use nonlinear dynamics measurements may commit fewer classification errors due to QRS undersensing and aid therapy decisions when circumstances suggest that QRS sensing is inaccurate.
Ventricular Fibrillation Resulting from Synchronized Internal Atrial Defibrillation in a Patient with Ventricular Preexcitation
Authors: BAROLD HELEN S. , WHARTON J. MARCUS
Published: April 2007

VF After Synchronized Internal Atrial Defibrillation. This case describes ventricular proarrhythmia as a result of a synchronized internal atrial defibrillation shock in a 29‐year‐old man with Ebstein's anomaly referred for radiofrequency ablation of a right posterior accessory pathway. During the electrophysiologic study, atrial fibrillation was induced and 3/3 msec shocks of various strengths were delivered between two decapolar defibrillation catheters in the coronary sinus and right atrial appendage. A 2.0‐J biphasic shock synchronized to an R wave after a short‐long‐short ventricular cycle length pattern with a preshock coupling interval of 245 msec induced ventricular fibrillation, which was externally defibrillated with 200 J. This observation has implications for the development of implantable atrial defibrillators.
Idiopathic Left Ventricular Tachycardia with Left and Right Bundle Branch Block Configurations
Authors: ZIVIN ADAM , GOYAL RAJIVA , DAOUD EMILE , MAN K. CHING , STRICKBERGER S. ADAM , MORADY FRED
Published: April 2007

Fascicular Tachycardia. Introduction: Idiopathic left ventricular tachycardia typically has a right bundle branch block configuration. The purpose of this case report is to demonstrate that idiopathic ventricular tachycardia arising in or near the left posterior fascicle also may have a left bundle branch block configuration.

Methods and Results: A 27‐year‐old woman underwent an electrophysiologic procedure because of recurrent, verapamil‐responsive, wide QRS complex tachycardia. Two types of ventricular tachycardia (cycle lengths 330 to 340 msec) were reproducibly inducible, one with a right bundle branch block configuration and left‐axis deviation that had been documented clinically, and the other with a left bundle branch block configuration and axis of zero. A Purkinje potential recorded at the junction of the left ventricular mid‐septum and inferior wall preceded the ventricular complex by 40 msec in both tachycardias. A single application of ra‐diofrequency energy at this site successfully ablated both ventricular tachycardias.

Conclusion: The findings of this case report demonstrate that idiopathic ventricular tachycardia arising in or near the left posterior fascicle may have a left bundle branch block configuration
Tachycardia‐Induced Cardiomyopathy Secondary to Right Ventricular Outflow Tract Ventricular Tachycardia: Improvement of Left Ventricular Systolic Function After Radiofrequency Catheter Ablation of the Arrhythmia
Authors: VTJGEN JOHAN , HILL PHILIP , BIBLO LEE A. , CARLSON MARK D.
Published: April 2007

Cardiomyopathy Secondary to RVOT VT. Introduction: Several reports describe development of cardiomyopathics secondary to supraventricular tachycardia. Few reports have described cardiomyopathies secondary to ventricular tachycardia.

Methods and Results: We describe a patient who presented with dilated cardiomyopathy and repetitive nonsustained monomorphic ventricular tachycardia. Cardiac cathcterization showed hemodynamically insignificant coronary artery disease. Radiofrequency ablation of a right ventricular outflow tract ventricular tachycardia resulted in improvement of the left ventricular systolic function and resolution of heart failure symptoms.

Conclusions: This report suggests that right ventricular outflow tract ventricular tachycardia may cause reversible tachycardia‐induced cardiomyopathy.
Comparison of the Rate‐Dependent Properties of the Class III Antiarrhythmic Agents Azimilide (NE‐10064) and E‐4031
Authors: GROH WILLIAM J. , GIBSON KEVIN J. , MAYLIE JAMES G.
Published: April 2007

Rate Dependence of Azimilide and E‐4031. Introduction: Reverse rate‐dependence, a lessening in Class III antiarrhythmic agent action potential duration (APD) prolongation as heart rate is increased, has been proposed to be related to an incomplete deactivution of the slow component (IKs) of the delayed rectifier K+ current (IK). The rate‐dependent properties of block of IK by azimilide were compared to E‐4031, which selectively blocks the rapid component (IKr) of Ik, in guinea pig ventricular muscle.

Methods and Results: Azimilide prolonged APD in isolated papillary muscles in a concentration‐dependent manner and to a greater degree than E‐4031. Both agents prolonged APD less at fast than slow rates, consistent with a similar reverse rate‐dependent effect. Isolation of azimilide block of IKs by subtraction of APD during E‐4031 plus azimilide from E‐4031 alone revealed rate‐independent prolongation of APD. In voltage clamp experiments on single ventricular myocytes, activation of Iks was similar following 30 seconds of conditioning pulses of physiological duration (125 to 200 msec) with either a fast (cycle length 250 msec) or slow (cycle length 2000 msec) rate. The block of IKs by azimilide 3 μM was greater after a fast conditioning pulse train.

Conclusions: Selective block of Iks prolongs APD in a rate‐independent manner. In voltage clamped myocytes, no evidence of a rate‐dependent accumulation of IKs was observed. These findings support a mechanism of reverse rate‐dependent APD prolongation by Class III antiarrhythmic agents that block IKr independent of IKs.
Successful Radiofrequency Catheter Ablation of Sustained Ventricular Tachycardia Postmyocardial Infarction in Man Guided by a Multielectrode “Basket” Catheter
Authors: GREENSPON ARNOLD J. , HSU STEVE S. , DATORRE STEVEN
Published: April 2007

Multielectrode “Basket” Catheter. Currently, analysis of sustained ventricular tachycardia postmyocardial infarction in man is limited by the time required for single point activation mapping and the difficulty in obtaining information during hemodynamically unstable arrhythmias. To overcome these limitations, we developed a multielectrode “basket” catheter for endocardial recording and pacing. This report describes the first clinical use of such a catheter to guide successful radiofrequency ablation of incessant sustained ventricular tachycardia postmyocardial infarction. This system may significantly shorten the time required for VT analysis and improve the results of radiofrequency catheter ablation for VT postmyocardial infarction.
Book Review
Authors: Epstein Andrew E.
Published: April 2007

Interventional Electrophysiology. Edited by Igor Singer.
Abnormal Action Potential Conduction in Isolated Human Hypertrophied Left Ventricular Myocardium
Authors: McINTYRE HUGH , FRY CHRISTOPHER H.
Published: April 2007

AP Conduction in Hypertrophied Myocardium. Introduction: Cardiac hypertrophy is associated with an increased incidence of arrhythmias that result from altered action potential configuration or propagation velocity. These variables were measured in isolated preparations of human left ventricular myocardium and correlated with the degree of hypertrophy.

Methods and Results: Cardiac mass was estimated by echocardiography and cell diameter was measured from fixed isolated specimens; the two variables correlated significantly. Action potential duration was measured under field stimulation but was independent of the degree of hypertrophy; however, the duration was longer in septal preparations (405 ± 12 msec, 37°C, 1‐Hz stimulation) than in papillary muscles (342 ± 11 msec). Conduction velocity decreased progressively as cell diameter increased both in septal and papillary muscle preparations. Cable analysis showed that the variation of conduction velocity could be accounted for adequately by an increase of the intracellular resistivity of the preparations.

Conclusion: The data suggest that conduction defects occur in a progressive manner in human hypertrophy, which would provide an important substrate for dysrhythmias in human left ventricular hypertrophy and could result from a decrease of electrical coupling between adjacent myocardial cells.
Symptomatic Atrioventricular Block in an Atriofascicular Pathway Inserting into the Left Bundle Branch Without Apparent Atrioventricular Node Function
Authors: MECCA ANDREW , TELFER ANDREW , LANZAROTTl CHARLES , OLSHANSKY BRIAN
Published: April 2007

Atriofascicular Pathway with AV Block. We report a patient with symptomatic AV block associated with conduction solely through an atriofascicular pathway that inserted into the left bundle branch. There was no apparent conduction present through the AV node. There was, however, passive activation through the His‐Purkinje system. His‐bundle pacing demonstrated normal conduction through both right and left bundles. This is the first report of such a case.
Inappropriate Discharge of an Implantable Cardioverter Defibrillator During Atrial Flutter and Intermittent Ventricular Antibradycardia Pacing
Authors: PETERS WERNER , KOWALLIK PETER , WITTENBERG GÜNTER , SCHOLL CHRISTOPH , MEESMANN MALTE
Published: April 2007

Inappropriate Discharge of an ICD. Introduction: Inappropriate discharses of an implantable cardioverter defibrillator (ICD) are troublesome to the patient and sometimes a difficult task for the physician trying; to identify and treat the cause.

Methods and Results: For the first time, we report a mechanism of inappropriate ICD discharges during episodes of atrail flutter with a slow ventricular response and intermittent antibradycardia pacing. The episodes occurred in tow patients and were triggered by the unique sensing alogorithm of the Ventitex Cadence® V‐100 in combination with the tripolar CPI Endotak® 072 transvenous defibrillation lead, which provides integrated bipolar sensing.

Conclusion: Besides treatment of the underlying arrhythmia, reprogramming of the device, an electrode position far away from the atria, and true bipolar sensing will enhance the performance of ICD systems with respect to the episodes described here. In addition, more flexible sensing algorithms may. in the future, prevent this overall rare complication.
Reproducibility of Ventricular Fibrillation Characteristics in Patients Undergoing Implantable Cardioverter Defibrillator Implantation
Authors: TANEJA TARESH , GOLDBBRGER JEFFREY , PARKER MICHELLE A. , JOHNSON DAVE , ROBINSON NIKKI , HORVATH GEORGE , KADISH ALAN H.
Published: April 2007

Reproducibility of VF Characteristics. Introduction: The purpose of this study was to evaluate the immediate reproducibility of local electrogram characteristics recorded during repeated episodes of induced ventricular fibrillation (VF) in patients undergoing implantable cardioverter defibrillator (ICD) implantation.

Methods and Results: Power spectral analysis (using a fast Fourier transform algorithm) of electrograms recorded during 3 seconds of VF were analyzed in 24 patients undergoing ICD implantation using a Medtronic Transvene lead. Patients had 2 to 7 episodes of VF that were induced during defibrillation threshold testing. VF was induced by burst pacing (n = 20) or T wave shock (n = 4). Simultaneous electrograms during VF were recorded from a Medtronic Transvene lead with the following configurations: (1) a narrow spaced (12 mm) dedicated bipole used clinically for sensing; (2) a unipolar electrogram from the right ventricular coil; and (3) a widely spaced (18.3 mm) integrated bipole using the distal tip and the coil. Intraclass correlation coefficients (ICCs) were determined to examine the reproducibility of these VF characteristics among VF episodes in each patient. Recordings from both bipolar configurations had ICCs from 0.40 to 0.55, whereas unipolar recordings ICCs were below 0.40. Reproducibility was similar for dedicated and integrated recordings.

Conclusions: Frequency characteristics of repeated episodes of VF induced in the same subjects show fair‐to‐good but not excellent reproducibility. Bipolar recordings were far more reproducible than unipolar recordings, but both bipolar configurations had similar reproducibility. These findings have implications for both the pathophysiology of induced VF and the design of VF detection algorithms.
A Case of Widely Split Double P Waves with Marked Intra‐Atrial Conduction Delay
Authors: SOEJIMA KYOKO , MITAMURA HIDEO , MIYAZAKI TOSHIHISA , AKAISHI MAKOTO , MIYOSHI SHUNNICHIRO , OGAWA SATOSHI , TANI MASATO , SHINNMURA KEN , NAKAMURA YOSHIRO
Published: April 2007

Widely Split Double P Wave. We report a 78‐year‐old man as the first documented case of double P waves separated by 400 msec on 12‐lead ECG. These P waves had different polarities on lead V1. The first P wave represented activation of the lateral wall of the right atrium, and the latter P wave represented activation of the nudial right atrium and the left atrium. Widely spaced double potentials were recorded craniocaudally along the line, presumably corresponding to the crista terminalis during sinus rhythm. For this to occur, conduction disturbance has to be present both in the upper and lower right atrium. Conduction disturbance in the upper right atrium would interrupt excitation from the sinus node to the medial wall, and conduction disturbance in the lower right atrium would interrupt excitation spreading from the lower lateral right atrium to the isthmus area where fragmented potentials were recorded. These multiple discrete lesions appear to constitute a unique electrical atriopathy in this patient.
Three‐Dimensional Distribution of ST‐T Wave Alternans During Acute Ischemia
Authors: GREEN LARRY S. , FULLER MICHAEL P. , LUX ROBERT L.
Published: April 2007

Repolarization Alternans in Ischemia. Introduction: A canine model of reversible ischemia was used to measure the magnitude and transmural distribution of repolarization alternans.

Methods and Results: Twenty‐four multielectrode needles were inserted into a reversibly ischemic region created by 8 minutes of coronary occlusion. One hundred ninety‐two unipolar electrograms were simultaneously recorded at 1‐minute intervals for 8 minutes of ischemia and 3 minutes of reflow recovery. Beat‐to‐beat repolarization alternans was quantified for all electrograms using the standard deviation of QRST integrals. When alternans from animals that fibrillated was compared with alternans from animals that did not, the magnitude of alternans in the fibrillation group was an average standard deviation of 1125 ± 99.7 mV‐msec at the time of fibrillation and 409 ± 183 mV‐msec at 8 minutes of ischemia in the animals that did not fibrillate. The increase in alternans occurred mainly in the mid‐myocardial and epicardial regions in the animals that fibrillated. QRS morphology of sequential electrograms did not differ in beat‐to‐beat comparison, suggesting that repolarization alternans measured was not due to alternating conduction block in the region of reversible ischemia.

Conclusion: During acute ischemia, the magnitude and distribution of repolarization alternans are greater and differ in hearts that experience ventricular fibrillation. This observation may have clinical utility in arrhythmia prediction. It also is consistent with the possibility there may be multiple mechanisms for repolarization alternans.