bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymatic activity, osmotic stress and degradation of pesticide mixtures in soil extract liquid broth inoculated withPhanerochaete chrysosporiumandTrametes versicolor
Authors: Fragoeiro Silvia , Magan Naresh
Published: January 2005

In this study we examined the extracellular enzymatic activity of two white rot fungi (Phanerochaete chrysosporiumandTrametes versicolor) in a soil extract broth in relation to differential degradation of a mixture of different concentrations (0–30 p.p.m.) of simazine, dieldrin and trifluralin under different osmotic stress (−0.7 and −2.8 MPa) and quantified enzyme production, relevant to P and N release (phosphomonoesterase, protease), carbon cycling (β‐glucosidase, cellulase) and laccase activity, involved in lignin degradation. Our results suggest thatT. versicolorandP. chrysosporiumhave the ability to degrade different groups of pesticides, supported by the capacity for expression of a range of extracellular enzymes at both −0.7 and −2.8 MPa water potential.Phanerochaete chrysosporiumwas able to degrade this mixture of pesticides independently of laccase activity. In soil extract,T. versicolorwas able to produce the same range of enzymes asP. chrysoporiumplus laccase, even in the presence of 30 p.p.m. of the pesticide mixture. Complete degradation of dieldrin and trifluralin was observed, while about 80% of the simazine was degraded regardless of osmotic stress treatment in a nutritionally poor soil extract broth. The capacity of tolerance and degradation of high concentrations of mixtures of pesticides and production of a range of enzymes, even under osmotic stress, suggest potential bioremediation applications.
Catabolism of sulfamate by Mycobacterium sp. CF1
Authors: Fulton Craig K. , Cooper Ronald A.
Published: January 2005

A bacterium able to utilize sulfamate as N‐source for growth was isolated from soil and identified as a Mycobacterium sp. An apparently previously unrecorded enzyme, sulfamate hydrolase (EC 3.10.1.‐), converts sulfamate to equimolar amounts of ammonia and sulfate. This enzyme was purified to homogeneity and had a Km for sulfamate of 26.36 ± 4.01 mM. Its Specificity Constant value, 74 M−1 s−1, was low, indicating that it was not a particularly good catalyst for this reaction and it may be a hydrolase recruited to this role from some other reaction sequence. However, under equivalent conditions it showed no detectable action on the other sulfamates, cyclamate and sulfamoylbenzoate, or on urea or methylamine.
Role of iron and the TonB system in colonization of corn seeds and roots by Pseudomonas putida KT2440
Authors: Molina María Antonia , Godoy Patricia , Ramos‐González María Isabel , Muñoz Nuria , Ramos Juan L. , Espinosa‐Urgel Manuel
Published: January 2005

Iron, which is abundant in corn (Zea mays L.) seeds, plays an important role in the initial establishment of Pseudomonas putida KT2440 populations on seeds. Sequestration of seed‐borne iron by chelators decreases the capacity of KT2440 to initiate attachment to corn seeds. The importance of iron for this plant–bacteria interaction is further supported by the fact that mutations in the TonB system, which is key for iron uptake, result in reduced seed colonization. TonB is also a primary determintant of the fitness of P. putida in the rhizosphere, as a deletion mutant shows a clear competitive disadvantage during colonization of corn roots.
Frequent genetic recombination in natural populations of the marine cyanobacterium Microcoleus chthonoplastes
Authors: Lodders Nicole , Stackebrandt Erko , Nübel Ulrich
Published: January 2005

A culture‐independent method for multilocus sequence typing of Microcoleus chthonoplastes was developed based on mechanical separation of individual cyanobacterial filaments from natural microbial mat populations through micromanipulation, subsequent polymerase chain reaction (PCR) amplification and sequence analysis of three genetic loci (kaiC, petB/D, rDNA‐ITS). Among 81 individuals sampled from intertidal sand flats of the North Sea and Baltic Sea, we found 8–14 different sequences (alleles) per genetic locus, resulting in 36 distinct genotypes with unique allele profiles. Non‐congruent phylogenetic gene trees for the three loci analysed and split decomposition analysis indicated the occurrence of horizontal genetic exchange. The index of association determined for the entire population was 0.096, indicating that recombination occurs frequently enough to cause almost random association (linkage equilibrium) among alleles. Analysing individuals from three different locations in the North Sea and Baltic Sea, we did not find evidence for geographic subdivisions between populations.
TRANSPORTATION REGIONS AND THE EASTWARD INTEGRATION OF EUROPE
Authors: BUCKWALTER DONALD W.
Published: January 2005

Transportation facilities and performance indicate the prospects for East‐West integration in Europe. The purpose of this study is to identify and delineate regions that present particular challenges for the optimistic enlargement policy of the European Union (EU). A sequence of statistical methods – correlation, regression, and cluster analysis – reveal that the East‐West dichotomy between former communist and non‐communist countries was still the strongest cleavage in Europe as recently as 1997. Secondary cleavages include western subgroups – more or less road oriented – and three eastern subgroups – a Central and Eastern European (CEE) core, southeastern countries, and particularly underdeveloped countries that also have southeasterly location. Results of four cluster methods persistently reveal differences between the established EU members (15 as of 2003) and the eight former communist countries included in the 2004 accession. They also indicate that the eight are, indeed, the best candidates from the former Soviet bloc.
GEOGRAPHICAL ACCESS TO CHILDCARE AND MOTHERS’ LABOUR‐FORCE PARTICIPATION
Authors: VAN HAM MAARTEN , MULDER CLARA H.
Published: January 2005

This paper addresses the question whether geographical access to institutionalised childcare influences mothers’ labour‐force participation in the Netherlands. The conceptual framework of the paper is based on a time‐geographic perspective of female labour‐force participation. According to this perspective, women are faced with severe day‐to‐day space‐time constraints that form a spatial barrier to labour‐force participation. It is argued that, for many mothers with pre‐school‐age children, access to employment opportunities is partly determined by geographical access to childcare facilities. Using data from the Netherlands Housing Demand survey and a detailed measure of geographical access to childcare, it is shown that, for mothers with young children, the probability of being engaged in paid employment increases as the number of day‐care slots per 100 children in the residential area increases. In the regression model, the effect of access to childcare on mothers’ labour‐force participation is estimated after individual, household, and local labour market characteristics are controlled for.
SAINT HELENA: CITIZENSHIP AND SPATIAL IDENTITIES ON A REMOTE ISLAND
Authors: HOGENSTIJN MAARTEN , VAN MIDDELKOOP DANIËL
Published: January 2005

Saint Helena is an extremely isolated island in the South Atlantic. It is connected to the outside world through the Internet, telephone and a shipping link. Its inhabitants, who call themselves Saints, were denied full British citizenship until May 2002. This prevented a large out‐migration. At the same time the struggle for citizenship provided a common cause, which united the people of Saint Helena. With the return of citizenship, an escape route became available. Roughly a quarter of the island's population has since left ‘prison home’ Saint Helena. Two options are now open, which will both bring major change to the island. Air access might bring much‐needed economic development, but it will also have an impact on the Saints’ identity and ‘way of life’. Without air access, more Saints will probably leave and this way of life will be shared by less and less people on the island.
Student retention: an exploration of the issues prevalent on a healthcare degree programme with mainly mature students
Authors: Trotter Eileen , Cove Geoff
Published: January 2005

This article explores students’ experiences during the first year of a degree programme in a department within the school of healthcare professions in a UK university. The numbers of students on the course has increased by 30% between 2000/01 and 2003/04, and the percentage of mature (> 21 years of age) entrants has increased from 46% to 80% within the same time‐period. There is concern at the numbers of students electing to leave the programme within their first year, and this research has been carried out to obtain students’ perceptions of the programme and to determine if there is anything that can be done to curb the attrition rate. Focus groups were conducted with students in the first year of the programme, and students who had withdrawn were interviewed. The main topics focused on by students were integration, issues concerning a mixed age‐group of students, the relationship between education and career, and balancing studies with other life commitments. The results of this study should be of interest to those who are concerned about student retention within the current higher education environment of increasing and widening participation.
The missing piece: Measuring portfolio salience in Western European parliamentary democracies
Authors: DRUCKMAN JAMES N. , WARWICK PAUL V.
Published: January 2005

Abstract. Although much has been discovered concerning the resources and preferences that parties take into the coalition formation game in Western European parliamentary democracies, we know a good deal less about the payoffs they receive. Portfolios constitute an important payoff, not just because they provide access to patronage, but because influence over policy decisions tends to go with control over the key government portfolios. It is easy to discover which and how many portfolios each party holds in any government, but what is missing is accurate measurement of the value or salience of these portfolios. Some attempts have been made to measure portfolio salience, but they have lacked one or more of the following properties: cross‐national scope, country‐specific measurement, coverage of the full set of postwar portfolios, measurement by multiple experts and measurement at the interval level. In this article, we present a new data contribution: a set of portfolio salience scores that possesses all of these properties for 14 Western European countries derived from an expert survey. We demonstrate the comprehensiveness and reliability of the ratings, and undertake some preliminary analyses that show what the ratings reveal about parliamentary government in Western Europe.
The institution of ‘consensus’ in the European Union: Formal versus informal decision‐making in the Council
Authors: HEISENBERG DOROTHEE
Published: January 2005

Abstract.  Although many have studied European Union (EU) decision‐making in order to evaluate where the locus of power is, most studies have relied on the formal decision‐making rules in the first pillar to theorize the workings of the EU. This assumption is somewhat problematic given that the informal norms of consensus are the primary mode of decision‐making (81 per cent of decisions are made by consensus). This article examines the institution of consensus in the EU. It argues that the informal norm of consensus renders implausible the fundamental assumption of the rational institutionalist literature, challenging the validity of its claims. Finally, the costs and benefits to the EU's perceived legitimacy are examined with the argument that the putative benefits of consensual decision‐making do not obtain in the EU and that the institution of consensus – the lack of voting and thus accountability – actually contributes to the perception of a democratic deficit in the Council.
Policy positions and jobs in the government
Authors: GIANNETTI DANIELA , LAVER MICHAEL
Published: January 2005

Abstract.  This article conducts a theoretical and empirical analysis of the allocation of the full set of jobs – both cabinet and junior ministers – in the Prodi Government that formed after the Italian election of 1996. We first discuss theoretical arguments linking forecasts of government policy to the policy positions of both cabinet and junior ministers. We then estimate the policy positions of cabinet and junior ministers appointed to the Prodi cabinet, applying a new technique for computerized content analysis to the collected legislative speeches of each minister during the 1996–1997 parliamentary session. Having considered the face validity of these results, we then use them to explore to observable implications of the various theoretical approaches. We conclude that, in this case, there does appear to be systematic evidence linking both the allocation of government jobs and the evolution of spending patterns between departments to the policy positions of senior politicians.
On the theory and practice of party formation and adaptation in new democracies
Authors: VAN BIEZEN INGRID
Published: January 2005

Abstract. In addressing issues of party development in contemporary democracies, many of the recent discussions confuse notions of party formation with those of party adaptation. The contention of this article is that the conceptual confusion of these two distinct processes undermines our understanding of party development, which is of particular importance in the context of the more recently established democracies. Moreover, in order to contribute to theory building on political parties more generally, it is necessary to differentiate between the two. This article offers some theoretical contours for the study of party formation and development, and empirically evaluates the patterns of organizational development in some of the newer democracies in Southern and East‐Central Europe. The analysis shows that the external context of party formation has encouraged these parties to adopt an organizational style largely resembling their contemporary counterparts in the older democracies. However, despite the resemblance between party organizations in the older liberal democracies and the newly established ones, the paths of party development are best understood as processessui generis. The historical uniqueness of parties emerging as strong movements of society, as opposed to agents of the state, is a path that is unlikely to be repeated in contemporary polities which democratize in a different institutional context.
Turkey's changing security discourses: The challenge of globalisation
Authors: BILGIN PINAR
Published: January 2005

Abstract.  The aim of this article is to analyse the ways in which Turkey's security discourses have been shaped by, and have sought to shape, the transformation Turkey has gone through in recent years. It was as a part of the process of joining the European Union (EU) that the challenge of globalised security was strongly felt in Turkey. Since the Helsinki decision of 1999 to include Turkey in the list of official candidates, there emerged an elite‐level debate regarding the security implications of the reforms demanded by the EU. Whereas the ‘Eurosceptics’ have underlined the need for a broad security agenda by making references to ‘globalised security’ while seeking to shape practices in defense of ‘national security’, the ‘pro‐EU’ actors have opened up Turkey's definition of ‘national security’ for debate thereby sowing the seeds of an alternative security discourse. The article falls into three sections. The first section discusses the relationship between security and globalisation and gives examples from the Turkish case. The second section looks at the ‘traditional’ discourse on security that has prevailed during the Republican era. The third section seeks to identify the changes in the 1990s in Turkey's security discourses by focusing on the debates on the EU. The article concludes by considering the likelihood of further changes in Turkey's security discourses.
Impact of Dual Chamber Pacing on the Incidence of Atrial and Ventricular Tachyarrhythmias in Recipients of Implantable Cardioverter Defibrillators
Authors: STROHMER BERNHARD , MERMI JOHANN , CASTELLANOS EDUARDO , MAYR HARALD , GILL JASWINDER , ABADIA ANTONIO ASSO , KUEHL MARTIN , WOLPERT CHRISTIAN
Published: January 2005

Recent observations suggest that frequent dual‐chamber pacing in recipients of implantable cardioverter defibrillators (ICD) may adversely influence clinical outcomes. This prospective, multicenter study examined the relationship between the frequency of atrial (%AP) and ventricular pacing (%VP) and the incidence of atrial (AT) and/or ventricular tachyarrhythmias (VT) in a standard ICD population. A total of 141 consecutive patients with primary and secondary ICD indications were studied. Continuous arrhythmia detection with a dual‐chamber ICD revealed paroxysmal AT in 60 (43%) and VT in 72 (51%) patients within 6 months of device implantation. Far‐field oversensing of ventricular signals occurred in 13% of all “atrial tachy response” mode switches. Without adjustment for covariates, a higher %AP was associated with an increased incidence of AT (P < 0.05). However, this association remained only weakly significant after adjustment for covariates using a multivariate model. High New York heart failure functional classes correlated significantly with AT (P = 0.02) and VT (P = 0.007). Rate‐modulated pacing, programmed in 1/3 of patients, correlated with occurrence of AT (P = 0.006), but not with occurrence of VT. With respect to dual‐chamber pacing, a %AP ≥ 48% combined with a %VP > 40% was associated with an increased probability for VT. In conclusion, AT and VT occurred frequently within 6 months after dual‐chamber ICD implantation. High rates of DDD/R stimulation were associated with a trend toward higher incidence of AT, VT, or both.
Cardiac Resynchronization Therapy:
Authors: BORIANI GIUSEPPE , FALLANI FRANCESCO , MARTIGNANI CRISTIAN , BIFFI MAURO , SAPORITO DAVIDE , GRECO CRISTIANO , ZIACCHI MATTEO , LEVORATO MAURIZIO , PONTONE GIULIA , VALZANIA CINZIA , DIEMBERGER IGOR , FRANCHI ROBERTO , BRANZI ANGELO
Published: January 2005

In patients with heart failure and wide QRS complex, cardiac resynchronization therapy (CRT) is associated with improvement of symptoms and cardiac function. This study examined the effects of a 3‐month period of CRT on left ventricular (LV) and right ventricular (RV) ejection fraction (EF) and on LV volumes, both at rest and during exercise. A CRT system was implanted in 15 patients with severe heart failure and wide QRS. Before implant and 3 months later, all patients underwent assessment of cardiac performance with equilibrium Tc99 radionuclide angiography with imaging in the best septal left anterior oblique view. Exercise was performed on a bicycle ergometer. At 3 months, a significant improvement in New York Heart Association functional class was observed, and radionuclide angiography showed a significant decrease in LV volumes and a significant increase in LVEF at rest, as well as a significant increase in LVEF during exercise. The remodeling processes associated with CRT did not appear to include RV function, since RVEF did not improve, and changes in RVEF did not correlate with changes in LVEF, neither at rest nor during exercise.
Edrophonium‐Induced Right Ventricular Outflow Tract Tachycardia
Authors: HACHIYA HITOSHI , AONUMA KAZUTAKA , YAMAUCHI YASUTERU , SEKIGUCHI YUKIO , IESAKA YOSHITO
Published: January 2005

Idiopathic right ventricular outflow tract‐ventricular tachycardia (RVOT‐VT) generally occurs when sympathetic nervous system activity is increased, though, in a few patients, it develops when parasympathetic nervous activity (PNA) is increased. Among 101 consecutive patients with RVOT‐VT confirmed by endocardial catheter mapping, 5 (4.9%) presented with nocturnal RVOT‐VT. Autonomic nervous balance was studied by heart rate variability (HRV) analysis from 24‐hour ambulatory electrocardiogram (ECG). Standard programmed ventricular stimulation (PVS), ventricular burst pacing, and drug provocation were performed to induce RVOT‐VT. In the studied five patients, the average number of mostly nocturnal ventricular premature contractions (VPCs) was 6649 ± 4472/day. Two patients had nocturnal nonsustained RVOT‐VT on 24‐hour ambulatory ECG recordings. The HRV analysis revealed that a progressive increase in high‐frequency power coincided with an increase in VPCs or development of RVOT‐VT at night, whereas low/high frequency ratio did not change significantly during the 24‐hour period. RVOT‐VT could not be induced by PVS, ventricular burst pacing, or isoproterenol or adenosine triphosphate i.v. However, RVOT‐VT could only be induced by edrophonium, 5 mg i.v., in all patients. An increase in PNA was observed in a few patients before the development of RVOT‐VT. Edrophonium facilitated induction of RVOT‐VT in such patients.
Sympathovagal Balance Prior to Onset of Repetitive Monomorphic Idiopathic Ventricular Tachycardia
Authors: ZIMMERMANN MARC
Published: January 2005

Repetitive monomorphic idiopathic (RMI) ventricular tachycardia (VT) occurs typically in patients without structural heart disease, originates in most cases from the right ventricular outflow tract, and can often be induced by exercise or isoproterenol. This study analyzed the dynamic changes in autonomic tone immediately before the spontaneous onset of RMIVT using frequency‐domain heart rate variability (HRV) indices. We analyzed the ambulatory electrocardiographic recordings from 6 men and 8 women (mean age: 43 ± 18 years; mean number of VT runs per day: 134 ± 213; mean VT rate: 194 ± 40 bpm; median VT run length: 4 cycles) with RMIVT. A total of 36 clusters of nonsustained episodes of RMIVT preceded by ≥1 hour of sinus rhythm without VT were analyzed (25 minutes before the onset of RMIVT divided into five 5‐minute periods; 8 minutes before onset of RIMVT divided into eight 1‐minute periods). During 25 minutes preceding the onset of VT, the mean RR interval decreased from 767 ± 118 to 723 ± 105 ms (P = 0.015) and the low‐frequency (LF)/high‐frequency (HF) ratio increased from 2.24 ± 0.79 to 2.49 ± 1.0 (P = 0.03). During the 8 minutes before VT onset, the mean RR interval decreased from 745 ± 118 to 718 ± 102 ms (P = 0.001) and the LF components increased from 205 ± 72 to 253 ± 113 ms (P = 0.014). No change in HF components was observed during the 25 or 8 minutes periods preceding the RMIVT onset. The changes in HRV indices suggest a strong time‐dependent primary activation of sympathetic tone prior to the occurrence of RMIVT. Withdrawal of vagal tone does not appear essential to the initiation of RMIVT clusters.
Long‐Term Results of Cryoablation with a New Cryoprobe to Eliminate Chronic Atrial Fibrillation Associated with Mitral Valve Disease
Authors: TADA HIROSHI , ITO SACHIKO , NAITO SHIGETO , HASEGAWA YUTAKA , KUROSAKI KENJI , EZURE MASAHIKO , KANEKO TATSUO , OSHIMA SHIGERU , TANIGUCHI KOICHI , NOGAMI AKIHIKO
Published: January 2005

The purpose of this study was to examine the performance of a new cryoprobe in the treatment of chronic atrial fibrillation (AF) associated with mitral valve disease. The study included 66 patients undergoing mitral valve replacement. The mean AF duration was 9.0 ± 9.0 years and mean left atrial (LA) was diameter 57 ± 10 mm. Cryoablation (−60°C) was applied to four pulmonary vein (PV) orifices over 2–3 minute. The spherical tip (2‐cm in diameter) of the cryoprobe is capable of ablating the left atrium near the PV, as well as the PV ostium with a single cryoablation. After cryoablation, mitral valve surgery or a combined surgical procedure were performed in 66 patients. There were no intraoperative complications. Sinus rhythm was restored in 60 patients (91%) immediately after the operation. Recurrent AF was treated with antiarrhythmic drugs and/or direct current cardioversion in 43 patients (72%). At discharge, 48 patients (72%) were in sinus rhythm. During a mean follow‐up period of 31 ± 16 months, 40 patients (61%) were in sinus rhythm with (29) or without antiarrhythmic drugs (11). In patients in sinus rhythm at the end of the follow‐up period, the duration of preoperative AF duration was significantly shorter (P < 0.05) and the preoperative LA diameter and cardiothoracic ratio were significantly smaller than in patients who were in AF (both for P < 0.005). Using this new cryoprobe, sinus rhythm was restored and maintained in 61% of patients with chronic AF and mitral valve disease with a 12–15 minute cryoablation procedure.
Carvedilol Versus Metoprolol in Patients Undergoing Direct Percutaneous Coronary Interventions for Myocardial Infarction: Effects on QT Dynamicity
Authors: BONNEMEIER HENDRIK , ORTAK JASMIN , TÖLG RALPH , WITT MAREN , SCHMIDT JÖRG , WIEGAND UWE K.H. , BODE FRANK , SCHUNKERT HERIBERT , RICHARDT GERT
Published: January 2005

Beta‐adrenergic blockers exert significant antiarrhythmic activity during ischemia and reperfusion. To further explore the beneficial effects conferred by alpha‐1‐adrenoceptor blockade on ventricular repolarization dynamicity in the acute phase of myocardial infarction (AMI), we compared carvedilol with metoprolol in the setting of primary percutaneous coronary intervention (PCI). In a prospective study, 100 consecutive patients undergoing primary PCI for AMI were randomized to metoprolol 200 mg/day versus carvedilol 25 mg/day. The first oral dose of study drug was administered and a 24‐hour ambulatory electrocardiogram recorded upon hospital admission. Slopes of the linear QT/RR regression were determined before and after reperfusion. A total of 38 recordings of patients treated with metoprolol and 34 recordings of patients with carvedilol were eligible for analysis of QT/RR slopes. The two study groups were similar with respect to age, gender, TIMI perfusion grades, ventricular function, duration of ischemia, and site and size of infarction. Mean RR‐ and QT‐intervals were similar to the metoprolol and carvedilol groups, before and after PCI. Likewise, there was no significant difference in QT/RR slopes between the metoprolol and carvedilol groups before PCI. In contrast, after PCI, there was a trend toward lower QT/RR slopes in the metoprolol group (from 0.18 ± 0.07 to 0.17 ± 0.08), and a significant decrease in QT/RR slopes in the carvedilol group (from 0.17 ± 0.07 to 0.14 ± 0.09). In patients undergoing successful direct PCI for AMI, treatment with carvedilol, in contrast to metoprolol, was associated with a significant decrease in QT–RR slopes, suggesting greater cardiac electrical stability.
Changes in Heart Rate, Heart Rate Variability, and Heart Rate Turbulence during Evolving Reperfused Myocardial Infarction
Authors: ORTAK JASMIN , WEITZ GUNTHER , WIEGAND UWE K.H. , BODE FRANK , EBERHARDT FRANK , KATUS HUGO A. , RICHARDT GERT , SCHUNKERT HERIBERT , BONNEMEIER HENDRIK
Published: January 2005

Depressed cardiac parasympathetic activity is associated with electrical instability and adverse outcomes after myocardial infarction (MI). Heart rate turbulence (HRT), reflecting reflex vagal activity, and heart rate variability (HRV), reflecting tonic autonomic variations are both reduced in the subacute phase of MI. However, the evolution of these components of cardiac autonomic control between subacute and chronic phase of MI has not been defined. We prospectively studied 100 consecutive patients with a recent first MI with ST‐segment elevation, who underwent successful direct percutaneous coronary interventions. Beta‐adrenergic blockers and angiotensin‐converting enzyme (ACE) inhibitors were administered according to the state‐of‐the‐art medical practice guidelines. HRT and HRV were measured from 24‐hour ambulatory electrocardiographic recordings 10 days and 12 months after the index MI. There was no significant difference in mean RR interval between the subacute and chronic phase of MI (875 ± 145 versus 859 ± 122 ms). Indices of HRV increased significantly during the observation period (SDNN: from 88.8 ± 26.8 to 116.0 ± 35.7 ms, P < 0.001; SDNNi: from 37.9 ± 15.9 to 46.0 ± 16.3 ms, P < 0.001; SDANN: from 79.6 ± 34.7 to 105.6 ± 35.4 ms, P < 0.001). In contrast, there were no significant changes in indices of HRT (turbulence onset: from −0.008 ± 0.022 to −0.012 ± 0.025%; turbulence slope: from 7.78 ± 5.9 to 8.06 ± 6.8 ms/beat). In contrast to reflex autonomic activity, there was a significant recovery of tonic autonomic activity within 12 months after MI. These different patterns of recovery of reflex versus tonic cardiac autonomic control after MI need to be considered when risk stratifying post‐MI patients.
QT‐Interval Turbulence Induced by Atrial and Ventricular Extrastimuli in Patients with Ventricular Tachycardia
Authors: SAVELIEVA IRINA , WICHTERLE DAN , CAMM JOHN A.
Published: January 2005

Atrial and ventricular premature beats (APB, VPB) cause consistent changes in the sinus‐cycle length known as heart rate (HR) turbulence. HR turbulence is described by turbulence onset (TO) and turbulence slope (TS). This article investigated into whether specific QT interval changes are associated with HR turbulence and whether these can be assessed using HR turbulence quantifiers. A total of 40 patients (54 ± 16 years, 34 men) referred for electrophysiological evaluation for ventricular tachycardia (VT) underwent a study protocol prior to programmed electrical stimulation. The protocol consisted of three consecutive series of atrial and ventricular stimulation with single extrastimuli delivered from the high right atrium and the right ventricular apex at a coupling interval decremented from 750 to 400 ms at a 50‐ms step. A 20‐second period of sinus rhythm was allowed between ES. Turbulence onset and TS after an APB and a VPB were calculated separately using a dedicated computer algorithm. Consistent changes in the QT interval (QT turbulence) were observed immediately after premature beats and were determined using TO. QT TO was calculated as a relative difference between the QT interval of the first sinus cycle after the induced premature beat and the mean of the QT intervals of the two sinus cycles preceding the premature beat. QT turbulence was present following both APBs and VPBs but was less pronounced after an APB. In contrast to negative VPB‐induced TO of HR turbulence reflecting early acceleration of the HR, VPB‐induced TO of QT turbulence was positive showing lengthening of the QT interval following a VPB. The subgroup analysis has shown that QT turbulence was significantly attenuated in patients with ischemic heart disease and a left ventricular (LV) ejection fraction (EF) ≤0.40 compared with those with nonischemic VT and left ventricular ejection fraction >0.40 (after an APB: 0.73 ± 0.31% vs 2.58 ± 0.31%, respectively, P = 0.0044; after a VPB: 1.18 ± 0.29% vs 4.40 ± 1.38%, respectively, P = 0.0026). Neither APB nor VPB produced late QT dynamics equivalent to TS of HR turbulence. QT‐interval turbulence occurs in association with HR turbulence following induced VPB and APB but QT dynamics is opposite to that of HR. It can be expressed as TO but not TS. Patients with ischemic VT and LV dysfunction exhibited significantly lower QT TO values than those with nonischemic VT and normal ventricular function.
A Decrease in Pulmonary Vein Diameter After Radiofrequency Ablation Predicts the Development of Severe Stenosis
Authors: BERKOWITSCH ALEXANDER , NEUMANN THOMAS , EKINCI OKAN , GREISS HARALD , DILL THORSTEN , KURZIDIM KLAUS , KUNISS MALTE , SCHNEIDER HANS J. , PITSCHNER HEINZ F.
Published: January 2005

A decrease in ostial pulmonary vein (PV) diameter was observed in patients on the day after radiofrequency ablation of atrial fibrillation (AF). This study examined whether a relative reduction in PV diameter on day 1 (RRPVD1) after the procedure predicts the late development of severe PV stenosis (PVS). The study included 104 consecutive patients (mean age = 55 years, range 46–61, 34 women) with drug refractory AF. Pulmonary vein diameter was measured using MR angiography (MRA) on the day before and on day 1 after the ablation procedure. The MRA was repeated every 3 months after the procedure. Severe PVS was defined as a >70% diameter reduction from the initial ostial diameter. The cut‐off of RRPVD1 was prespecified as 25% decrease in initial diameter. The data are presented as medians and interquartile range. A total of 357 PV were treated. The RRPVD1 was 0.0% (0.0–11.1%). Severe PVS was found in 18 PV during a follow‐up of 12 months (range 6–13). The log‐rank analysis confirmed a strong association between a RRPVD1 ≥25% and the development of PVS (hazard ratio: 7.1; 95% confidence interval 3.8–13.5, P < 0.0001). By multivariate Cox regression model, after adjustment of procedure variables, RRPVD1 was the strongest predictor of development of severe PVS. RRPVD1 ≥25% was a strong independent predictor of development of severe PVS.
A Clinical Study of Patients with and Without Recurrence of Paroxysmal Atrial Fibrillation After Pulmonary Vein Isolation
Authors: CHEN JIAN , HOFF PER IVAR , ERGA KNUT STÅLE , ROSSVOLL OLE , OHM OLE‐JØRGEN
Published: January 2005

Patients with paroxysmal atrial fibrillation (PAF) can be treated by pulmonary vein (PV) isolation. However, the recurrence rate after this procedure is relatively high. We sought to evaluate the quality of life (QOL) of patients with PAF recurrence after PV isolation and to analyze factors related to recurrences. Seventy‐two drug‐refractory PAF patients (59 men, 13 women, mean age 52 ± 10) were included. PV isolation was based on the disappearance of PV potentials recorded from a Lasso catheter after segmental ostium ablation. Automatic foci were observed in 47 patients (65.3%) during the procedure. A mean of 3.1 ± 0.9 PVs was isolated. Patients were followed for a mean of 10.3 ± 5.1 months, during which 27 experienced >1 episode of PAF. QOL was scored from 0 (situation before ablation) to 10 (no episode after ablation) based on a questionnaire completed by 69 patients (95.8%). QOL was judged very good in 26 patients (none with PAF recurrences), better in 30 (15 with PAF recurrences), unchanged in 11 (10 with recurrences), and worse in 2 patients with PAF recurrences. Longer histories of PAF and a lower percentage of patients with automatic foci identified during the procedure were observed in the group with, than in the group without recurrences (P < 0.05). PV isolation improved QOL in patients with PAF, including in patients with recurrences. The length of PAF history and observation of automatic foci may be of importance for recurrences of PAF during long‐term follow‐up.
Home Orthostatic Self‐Training in Neurocardiogenic Syncope
Authors: ABE HARUHIKO , KOHSHI KIYOTAKA , NAKASHIMA YASUHIDE
Published: January 2005

We assessed the efficacy of daily sessions of home orthostatic self‐training (30 minutes per session standing against the wall without moving) in the prevention of neurocardiogenic syncope in 37 patients. Of these, 10 patients were instructed to perform two sessions per day, 14 were instructed to perform a single session per day, and the remaining 13 were instructed to perform one session every other day. The patients who performed one to two sessions of training per day continued to do so over a 6‐month follow‐up period, during that time none of them experienced spontaneous syncope. Only 5 of 13 patients who were instructed to train once every two days were able to continue doing so over the 6‐month follow‐up period; however, no spontaneous syncope was observed in these five patients. The remaining 8 of 13 patients could not continue their home training, and syncope or presyncope recurred in three of them during follow‐up. We conclude that one session per day of home orthostatic self‐training should be prescribed for the prevention of neurocardiogenic syncope.
Long‐Term Follow‐Up of Patients with Refractory Heart Failure and Myocardial Ischemia Treated with Cardiac Resynchronization Therapy
Authors: DE COCK CAREL C. , VAN CAMPEN LINDA M.C. , JESSURUN EMILE R. , ALLAART COR A. , VOS DICK S. , VISSER CEES A.
Published: January 2005

Studies in patients without coronary artery disease have shown the restoration of glucose metabolism by cardiac resynchronization therapy (CRT) without changes in myocardial perfusion. We report on the long‐term outcome of CRT in 24 patients with severe heart failure (HF) and advanced coronary artery disease not amenable for revascularization. All patients had documented myocardial ischemia on stress 99Tc‐sestamibi single‐photon emission computed tomography, and all underwent successful implantations of CRT systems. The mean left ventricular ejection fraction was 21%± 4%, 19 patients (79%) had anginal complaints and 20 (83%) had diffuse three‐vessel disease. During a follow‐up of 13 ± 0.7 months, two patients died suddenly and one died of progressive HF. Among survivors, functional capacity decreased from New York Heart Association class 3.2 ± 1.4 to 2.1 ± 1.0 (P < 0.01), and the Minnesota questionnaire quality‐of‐life scores decreased from 43 ± 15 to 28 ± 13 (P < 0.01). Despite an increase from 264 ± 104 to 385 ± 121 m in distance walked in 6 minutes (P < 0.01), the number of anginal attacks/week remained unchanged (4.7 ± 0.7 to 4.5 ± 0.6). Patients with advanced HF, stable angina, and documented myocardial ischemia may undergo safe and successful implantations of CRT systems.
Serial Changes in Right Ventricular Apical Pacing Lead Impedance Predict Changes in Left Ventricular Ejection Fraction and Functional Class in Heart Failure Patients
Authors: STAMBLER BRUCE S. , ELLENBOGEN KENNETH A. , LIU ZHE , LEVINE PAUL , PORTER THOMAS R. , ZHANG XIAOZHENG ,   The ROVA Trial Investigators
Published: January 2005

Pacing impedance has been proposed to monitor the clinical status of patients with congestive heart failure (CHF). This study examined whether changes in right ventricular (RV) pacing impedance correlate with changes in left ventricular ejection fraction (LVEF) and New York Heart Association (NYHA) functional class during long‐term follow‐up in pacemaker recipients with CHF. The study included 67 patients, 70 ± 12 years of age, in NYHA class II or III, and with a mean LVEF = 29 ± 8% at implant. LVEF, NYHA class, and bipolar pacing impedance at the RV outflow tract (RVOT) and apex (RVA) were measured at implant and at 3, 6, 9, and 12 months of follow‐up. At implant, impedance was similar in RVOT (548 ± 115 Ω) and RVA (571 ± 174 Ω). Between implant and 3 months, mean impedance decreased (P < 0.0001) at both the RVOT (472 ± 62 Ω) and RVA (488 ± 86 Ω), LVEF increased (43 ± 14%, P < 0.0001), and the NYHA class decreased from 2.4 ± 0.5 to 2.1 ± 0.6 (P = 0.0001). Changes in RVA impedance correlated with changes in LVEF (r = 0.45, P = 0.002). A 50 Ω decrease in RVA impedance corresponded to a 3% decrease in LVEF. RVA impedance decreased significantly as NYHA class increased from I to IV (P = 0.04). There was no correlation between impedance measured at the RVOT and LVEF or NYHA class. A decrease in bipolar pacing impedance at the RVA was associated with worsening LVEF and the NYHA class. The use of pacing impedance to monitor the clinical status in CHF is dependent on the RV pacing site.
Specificity of Atrial Mode Switching in Detecting Atrial Fibrillation Episodes:
Authors: DE SIMONE ANTONIO , SENATORE GAETANO , TURCO PIETRO , VITALE DINO FRANCO , ROMANO ENRICO , STABILE GIUSEPPE
Published: January 2005

The number of automatic mode switch (AMS) has been used to measure the efficacy of atrial pacing in limiting atrial fibrillation (AF). We investigated the impact of length and contiguity on the specificity of AMS in detecting AF episodes in 24 recipients of dual chamber pacemakers with sick sinus syndrome and paroxysmal AF. An AMS algorithm and intracardiac electrogram recordings (IEGM) were activated in all patients to distinguish true arrhythmic events from unnecessary AMS. The length of AMS and the contiguity, that is, the probability of occurrence of another AMS within 5 minutes before or after AMS were examined to increase the specificity of the AMS. During a mean follow‐up of 5 ± 3 months, 250 AMS were collected. The IEGM analysis confirmed a true AF episode in 193 of 250 AMS (77.2%). Using the contiguity criterion, 47 of 57 (82.5%) inappropriate AMS episodes were isolated (there were no other AMS within 5 minutes), whereas 54 of 193 (27.9%) appropriate AMS episode were isolated. Adopting both length and contiguity criteria the specificity of AMS in detecting true AF episodes increased from 77.2% to 93.2% at the cost of 11.9% loss of original sensitivity. Combining the length and contiguity criteria, we were able to improve the specificity of the AMS in the detection of AF.
Predictive Value of High‐Sensitivity C‐Reactive Protein in Patients with Idiopathic Dilated Cardiomyopathy
Authors: LAMPARTER STEFFEN , GRIMM WOLFRAM
Published: January 2005

We analyzed the serum concentrations of high‐sensitivity C‐reactive protein (hsCRP) at the time of diagnostic cardiac catheterization in 198 patients with idiopathic dilated cardiomyopathy (IDC) to evaluate its prognostic value. Patients were dichotomized according to a median value of hsCRP of 2 mg/dL. Predefined study endpoints over 69 ± 33 months of follow‐up included major arrhythmic events and transplant‐free survival. Major arrhythmic events during follow‐up occurred in 20 of 98 patients (20%) with low, compared to 22 of 100 patients (22%) with high hsCRP (ns). By multivariate analysis, a depressed left ventricular ejection fraction (LVEF) was the only significant predictor of arrhythmic risk. Death or cardiac transplantation was observed in 36% of patients with high, versus 22% of patients with low hsCRP (P < 0.05). By multivariate analysis, hsCRP and LVEF were independent predictors of transplant‐free survival. Thus, in this patient population with IDC, hsCRP had independent prognostic value with regard to transplant‐free survival, but did not contribute in the stratification with regard to arrhythmic risk.
Serum Troponin I and Myoglobin After Monophasic versus Biphasic Transthoracic Shocks for Cardioversion of Persistent Atrial Fibrillation
Authors: KOSIOR DARIUSZ ARTUR , OPOLSKI GRZEGORZ , TADEUSIAK WIESŁAW , CHWYCZKO TOMASZ , WOZAKOWSKA‐KAPLON BEATA , STAWICKI SŁAWOMIR , FILIPAK KRZYSZTOF J. , RABCZENKO DANIEL
Published: January 2005

This study compared the effects of standard monophasic versus biphasic direct current shocks for cardioversion of atrial fibrillation (AF) on the release of cardiac troponin I (cTnI) and myoglobin (Myo). We randomized 48 patients with persistent AF (mean age = 61.4 ± 10.7 years, 33 men) to monophasic (45.2%) or biphasic (54.8%) cardioversion. Plasma concentrations of cTn1 and Myo were measured before, and 6 and 24 hours after the procedure. Cardioversion was significantly more effective (88% vs 100%, P < 0.04) and required less energy (348.1 ± 254.1 vs 187.6 ± 105.3 J; P < 0.001) in the biphasic than the monophasic group. A significant increase in mean plasma cTnI concentration over 24 hours (0.23 ± 0.18 vs 0.41 ± 0.37 ng/mL, P < 0.04), and mean Myo concentration were recorded in the monophasic group over the first 6 hours following the procedure (38.2 ± 14.2 vs 221.9 ± 51.3 ng/mL, P < 0.001), whereas no significant increase was observed in the biphasic group. Increases in cTnI and Myo in the monophasic group correlated closely with the cumulative energy delivered (Spearman correlation coefficient r = 0.58, P = 0.004 for Myo and r = 0.67, P < 0.001 for cTnI). In addition, there was a positive correlation between cumulative cardioversion energy load and increase in Myo and cTnI indexed with left ventricular mass (r = 0.45, P < 0.02 for Myo and r = 0.47, P = 0.01 for cTnI). It is concluded that in cardioversion of AF, biphasic are more effective than monophasic and may cause less myocardial injury.
Hormone Replacement Therapy Does Not Affect the 24‐Hour Heart Rate Variability in Postmenopausal Women:
Authors: FERNANDES ENEY O. , MORAES RUY S. , FERLIN ELTON L. , WENDER MARIA CELESTE O. , RIBEIRO JORGE P.
Published: January 2005

Postmenopausal women are at greater risk of coronary heart disease. The results of previous studies of the effects of hormone replacement therapy (HRT) on cardiac autonomic modulation in postmenopausal women have been contradictory. This study examined whether continuous treatment for 3 months with estradiol alone (ERT) or with estradiol plus norethisterone (HRT), increases 24‐hour heart rate variability (HRV) in postmenopausal women. In this double‐blind, placebo‐controlled trial, 40 healthy postmenopausal women, 46–63 years of age, were randomly assigned to (1) continuous 2 mg of estradiol plus 1 mg of norethisterone acetate daily (HRT, n = 13), or (2) 2 mg of estradiol daily (ERT, n = 14), or (3) placebo (n = 13). Before and after 3 months of therapy, blood estradiol concentrations were measured and 24‐hour electrocardiograms recorded for evaluation of 24‐hour time‐domain indices of HRV, and indices derived from the three‐dimensional return map. Both hormone replacement regimens significantly increased blood estradiol concentrations, while no change occurred in the placebo group. In the three treatment groups, multiple 24‐hour time‐domain indices of HRV and indices derived from the three‐dimensional return map remained unchanged. In healthy postmenopausal women, HRT with estradiol or estradiol and norethisterone for 3 months did not modify cardiac autonomic activity evaluated by 24‐hour indices of HRV. These findings are consistent with a lack of protective cardiovascular effect of HRT described in recent large randomized trials.
Defibrillation Effects of Intravenous Nifekalant in Patients with Out‐of‐Hospital Ventricular Fibrillation
Authors: IGARASHI MASAKI , FUJINO TADASHI , TOYODA MIWAKO , SUGINO KEISHI , SASAO KENICHIROU , SASAMOTO SHUICHI , OTSUKA TAKAYUKI , KOBAYASHI KENZABURO , OKANO YOSHIFUMI , YOSIWARA KATSUNORI , KOYAMA NOBUYA
Published: January 2005

Nifekalant (NF), a pure K+ channel blocker developed in Japan, has been reported to be effective in the treatment of life‐threatening ventricular arrhythmias. We studied its efficacy in 18 men and 4 women with out‐of‐hospital ventricular fibrillation (VF) admitted to our emergency department between August 2001 and March 2004. The number of DC shocks delivered for out‐of‐hospital VF, serum Na+ and K+, arterial blood pH, and base excess were compared in 8 patients treated with NF, 0.3 mg/kg i.v. followed by a continuous intravenous (group N) versus 14 patients treated with lidocaine, 2 mg/kg, i.v. (group C). The two groups were similar with respect to their baseline characteristics. Sinus rhythm returned in 5 of 8 patients in group N versus 2 of 14 patients in group C (P < 0.05). These seven patients were admitted to the intensive care unit, though all died within 1 month. The results of this study suggest that NF may be effective in defibrillation of out‐of‐hospital VF, though controlled studies are needed to confirm our observations.