bluuebunny/crossref_metadata_2025 huggingface dataset:
CHANGES IN TRADITIONAL URBAN AREAS AND IMPACTS OF URBAN REDEVELOPMENT: A CASE STUDY OF THREE NEIGHBOURHOODS IN NANJING, CHINA
Authors: WU FULONG , HE SHENJING
Published: January 2005

Since market‐oriented economy reform, China has experienced significant changes in urban landscapes and the internal structure of cities. Recent studies have provided some insightful understanding into urban changes at a macro‐scale, e.g. social and spatial segregation, the division between rural migrants and urban households, changes in land uses. To a lesser extent, urban changes are understood at the microscopic level of the neighbourhood. Urban (re)development has created many new urban landscapes. Meanwhile, traditional old urban areas still constitute a significant proportion of Chinese cities, and normally contain large concentrations of marginal population. Possessing the particular characteristics of long developing history, high population density, and low housing quality, traditional urban areas have also experienced different changes in the post‐reform period. This study, based on a field survey of three traditional urban areas in Nanjing, attempts to reveal the built environmental and socio‐economic changes which can be partly attributed to different levels of urban redevelopment. More importantly, the study highlights the significance of neighbourhood‐based social interaction to marginal population. Against the backdrop of massive urban displacement and rapid redevelopment, it is argued that the effect of dismantling neighbourhoods could be detrimental to a sustainable urban society and the positive social objectives should be seriously considered in the process of urban redevelopment.
MAPPING OF THE HOLY LAND: CONTEMPORARY RELIGIOUS MAPPING
Authors: COLLINS‐KREINER NOGA , MANSFELD YOEL
Published: January 2005

One hundred and one current maps of Israel were analysed for their modern mapping religious ele‐ments in respect of the Holy Land. The main issues of the study are which religious elements appear and their form of representation in the range of maps; the impressions that can be derived from the different maps; and the narratives that can be construed from this representation. The research methods applied were hermeneutics and semiotics. Narratives identified on the various maps were the ‘holy’ vs the ‘secular’ narrative, the ‘holy Christian’ narrative, the Jewish narrative, and the Muslim narrative. The Christian narrative proved the most dominant, while the Muslim narrative was rarely found in the maps, even in those with a ‘Palestinian’ narrative. Religious maps evinced a special carto‐graphic status because of their subjective nature and their attempt to combine contemporary reality with the tradition of maps of the ancient Holy Land. A ubiquitous finding was disregard for political issues, although the maps’ messages allow the map user to draw conclusions about ideology, images and conflicts. The semiotic method was found appropriate and suitable for reading the maps.
Surgical education in the balance: can the quality of clinically based learning be improved?
Authors: Brigley Stephen J. , Robbé Iain J.
Published: January 2005

A qualitative evaluation of basic surgical education at four Trust hospitals in England involved non‐participant observations and semistructured interviews of senior house officers (SHOs) in general surgery and orthopaedic surgery, and their surgeon educators (SEs). It found that the traditional notion of learning by apprenticeship still applied in the specialty of surgery. Many surgeons believed that changes in legislation, policies, strategies and service delivery were eroding opportunities for service‐based learning, with adverse long‐term effects on surgical education and standards. However, individual SEs, and one Trust in particular, provided evidence that the quality of learning in surgical practice can be improved.
Political trust and the vote in multiparty elections: The Canadian case
Authors: BÉLANGER ÉRIC , NADEAU RICHARD
Published: January 2005

Abstract. While the causes of declining political trust have been investigated extensively in the literature, much less empirical effort has been devoted to the study of its behavioural implications. This article focuses on the decline of trust in Canada during the period 1984 to 1993, and on its effect on Canadian voting behaviour. We build upon M.J. Hetherington's (‘The effect of political trust on the presidential vote, 1968–1996’,American Political Science Review93 (1999): 311–326) work to explore the impact of political trust on the vote and on abstention in a multiparty electoral context. Multinomial logit estimations are performed using individual‐level survey data from three Canadian federal elections. While distrust is shown to significantly affect electoral participation, thus acting as an alienating factor, the results indicate that decreasing trust acts more as a motivation to support third‐party alternatives. The study further demonstrates that, in a multiple party setting, ‘old‐line’ major parties electorally suffer from declining political trust, but some third parties benefit more from this phenomenon than others. Contrary to what was the case in the previous two elections, distrustful individuals in 1993 were more likely to vote for the Reform Party or the Bloc Québécois than support the New Democratic Party.
Value of Pre‐Hospital Discharge Defibrillation Testing in Recipients of Implanted Cardioverter Defibrillators
Authors: DELVECCHIO ALEXANDER , TRIVEDI HEATHER A. , FISHER JOHN D. , KIM SOO G. , FERRICK KEVIN J. , GROSS JAY N. , PALMA EUGEN C.
Published: January 2005

Opinions vary regarding the need to perform defibrillation testing prior to hospital discharge in recipients of state‐of‐the‐art cardioverter defibrillators (ICDs). Our protocol is to perform predischarge ICD testing 1 day after implant. This report includes 682 consecutive implants. Adverse observations at testing were grouped into (1) risk of defibrillation failure, (2) surgical complications, (3) sensing/pacing issues or narrow defibrillation margin warranting closer follow‐up, or (4) findings correctable by device reprogramming. Among the 682 patients, 63% had single‐chamber and 37% dual‐chamber or biventricular ICDs. In 48 patients (7%) there were 69 concerns and/or interventions, with overlaps among the four categories, including one failure to defibrillate (0.15%), and six other patients at risk. Surgical complications included 11 hematomas (1.6%), and six lead dysfunctions. Closer follow‐up was indicated in 19 patients (2.7%), for high pacing thresholds in seven, sensing issues in seven, and <10 J defibrillation margin in five. Device reprogramming was needed in 31 patients (4.5%), for tachycardia detection and therapy settings in 12, and for pacing/sensing functions in 22 patients. In eight patients ventricular fibrillation could not be induced. There was no morbidity or mortality due to testing. The state‐of‐the‐art ICDs delivering biphasic shocks are remarkably reliable. The routine pre‐hospital discharge defibrillation testing of such ICDs may be optional and left to the physicians’ discretion.
Circadian and Sex‐Dependent QT Dynamics
Authors: SREDNIAWA BEATA , MUSIALIK‐LYDKA AGATA , JARSKI PIOTR , KALARUS ZBIGNIEW , POLONSKI LECH
Published: January 2005

The dynamic QT relationship between the QT and RR intervals in normal individuals, including sex differences, has not been well examined. The aim of this Holter monitor‐based study was to assess circadian and sex‐related variations in QT dynamics in healthy subjects. The study population consisted of 50 healthy volunteers (mean age = 32 ± 6 years, 25 men), in whom 24‐hour digital Holter monitoring and QT interactive, beat‐by‐beat analyses were performed. The mean lengths of QT and RR intervals were measured from the 24‐hour recordings. In order to assess QT dynamics, QT/RR linear regression was performed, and the slope was calculated over 24 hour and for day and night periods, and both genders separately. In the whole population, the mean QT interval was 356.5 ± 19.2 ms and RR interval was 785.9 ± 80.7 ms. The mean value of the slope over 24 hour was 0.17 ± 0.03, though significantly steeper during the day (0.13 ± 0.03) than at night (0.09 ± 0.03, P < 0.001). The analysis of QT/RR dynamics over 24 hour revealed a significantly steeper slope in women (0.18 ± 0.03) than in men (0.16 ± 0.03, P = 0.006), as well as during daytime (0.14 ± 0.03 vs 0.12 ± 0.03, P = 0.04). Circadian variations and sex differences were observed in QT dynamics. The latter may explain the greater susceptibility of women to torsades de pointes during treatment with drugs that prolong repolarization.
No Correlation Between Atrial Natriuretic Peptide Concentrations and Echocardiographic Measurements of Left Atrial Size or Left Ventricular Size and Function in Patients with Persistent Atrial Fibrillation
Authors: WOŻAKOWSKA‐KAPLON BEATA , OPOLSKI GRZEGORZ
Published: January 2005

Atrial fibrillation (AF) may be associated with activation of atrial natriuretic peptide (ANP). The exact trigger for the release of ANP is still being debated. Atrial volume, pressure, and wall stretch are considered to be the main determinants of ANP activation. The aim of the study was to evaluate plasma ANP concentrations in patients with persistent AF and to analyze the echocardiographic determinants of ANP concentration in this group. The study population included 67 patients, 59 ± 7 years of age, with a median AF duration of 5.5 months (range 0.1–12). The relationship between plasma ANP concentrations and echocardiographic left atrial (LA) diameter and volume, and left ventricular (LV) diameter and ejection fraction (EF) was analyzed by logistic regression analysis. The median baseline plasma ANP concentration was 63 pg/mL (range 21–126) in the study group versus 34 pg/mL (range 16–73) in a control group. The mean left antero‐posterior atrial dimension, LA volume, LV enddiastolic diameter, and LVEF were 48 mm, 104 mL, 52 mm, and 54%, respectively. A significant linear positive correlation was found between plasma ANP concentration and maximal LA volume (r = 0.62, P < 0.01). A negative correlation was found between LVEF and plasma ANP concentration (r =−0.42, P = 0.01). However, by multivariate regression analysis, no echocardiographic parameter was an independent predictor of plasma ANP concentration. Plasma ANP concentrations were independent of echocardiographic measurements of LA size or LV size and function in patients with persistent AF.
Carvedilol Versus Metoprolol in the Acute Phase of Myocardial Infarction:
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 provide significant cardioprotection during acute ischemia and reperfusion. To further explore the effects of additional alpha‐1‐adrenoceptor blockade on autonomic modulation in acute myocardial infarction (AMI), carvedilol was compared with metoprolol in the setting of primary percutaneous coronary interventions (PCI). In a prospective study, 100 consecutive patients (61.1 ± 11 years; 23 females) undergoing primary PCI for AMI were randomly assigned to metoprolol 200 mg/day vs carvedilol 25 mg/day. The first oral dose of study drug was administered upon hospital admission, and a 24‐hour ambulatory electrocardiogram was recorded. A total of 40 recordings of patients assigned to metoprolol and 39 of patients assigned to carvedilol were eligible for analysis of heart rate turbulence. Turbulence onset (TO), turbulence slope (TS), and turbulence timing were measured after ventricular premature beats (VPBs). The mean value of the 10 preceding RR intervals (mean RR) before VPBs was also measured. There were no significant differences in mean age, gender distributions, TIMI perfusion grades, left ventricular ejection fraction, site and size of infarction, duration of ischemia, and mean 24‐hour heart rate between the two groups. Though the mean RR were not significantly different (metoprolol 863.1 ± 157 ms; carvedilol 839.6 ± 151 ms), there was a trend toward lower values of TO in the carvedilol group (−0.015 ± 0.016 vs −0.012 ± 0.023%; P = NS) and significantly higher values for TS in the metoprolol group (6.96 ± 5.8 vs 5.6 ± 4.22; P < 0.05). Turbulence timing was similar in both groups (metoprolol 5.8 ± 2.4 vs carvedilol 6.1 ± 2.1). In patients undergoing direct PCI for AMI, treatment with carvedilol, in contrast to metoprolol, was associated with a higher early acceleration and a lower deceleration of heart rate after VPBs, indicating differing effects on baroreceptor response due to additional alpha‐1‐adrenoceptor blockade. These data offer new insights into effects of a broader antiadrenergic therapy on autonomic reflexes in the acute phase of AMI.
Mechanism of Atrial Fibrillation:
Authors: COZMA DRAGOS , KALIFA JEROME , LIGHEZAN DANIEL , PESCARIU SORIN , DEHARO JEAN‐CLAUDE , MORNOS CRISTIAN , DJIANE PIERRE , DRAGULESCU STEFAN‐IOSIF
Published: January 2005

Atrial fibrillation (AF) has been associated with premature beats and decreased atrial conduction velocity. This study examined a new index of dynamic inter‐atrial conduction time (iaCT) in patients with paroxysmal AF (PAF). We compared 42 consecutive patients with paroxysmal AF (mean age = 52 ± 16 years) without structural heart disease with 39 age‐matched patients (mean age = 49 ± 15 years) who underwent ablation of junctional tachycardias. Prior to investigation, all antiarrhythmic drugs were discontinued for an appropriate period of time. The following measurements were made: baseline iaCT (iaCTb) between high right atrium (HRA) and distal coronary sinus, iaCT during HRA pacing S1S1 600 ms (iaCTS1), maximum prolongation of iaCT during S2 and S3 delivery (iaCTS2, iaCTS3). We then derived the decremental index (DI), the maximum percent prolongation of iaCT = iaCT S3‐iaCTS1/iaCTS1%. In patients with PAF, iaCTb was 81.3 ± 24 ms versus 59.5 ± 14 ms in controls (P = 0.0001). Atrial fibrillation was reproducibly and easily induced with a prominent increase in iaCT in 11 patients with AF. In this subgroup DI was 92 ± 17%, compared to 45 ± 21% in the other patients with AF (P = 0.0001) and 21 ± 15% in the control group (P = 0.0001). Spontaneous isolated or repetitive ectopic activity was observed in 11 patients with AF (26%), and decremental atrial conduction was observed in 76% of patients with AF. This study supports the role of dynamic inter‐atrial conduction disturbances in patients with lone PAF. The DI may be a new index of vulnerability to paroxysmal AF.
Long‐Term Results of Hybrid Therapy in Patients with Atrial Fibrillation Who Develop Atrial Flutter During Flecainide Infusion
Authors: TURCO PIETRO , DE SIMONE ANTONIO , LA ROCCA VINCENZO , EL JAMAL BILAL , NOCERINO PASQUALE , ASTARITA COSTANTINO , DE MATTEIS CARMINE , MESSINA VINCENZO , GRECO LUCIANO , ROTUNNO RAFFAELE , DI NAPOLI TOMMASO , VITALE DINO FRANCO , STABILE GIUSEPPE
Published: January 2005

The flecainide infusion test has been proposed to screen candidates for hybrid pharmacological and ablation therapy. We report the long‐term follow‐up of 154 consecutive patients with paroxysmal or persistent atrial fibrillation (AF) who developed atrial flutter (AFL) during flecainide infusion (IC AFL), treated with inferior vena cava‐tricuspid annulus isthmus catheter ablation and oral flecainide (hybrid therapy). Over a mean of 54.1 ± 13.1 months 82 patients (53%) remained free of AF and AFL. Flecainide was discontinued because of adverse effects in 6 patients (4%). A history of persistent AF, and the documentation of ≥1 spontaneous AFL episode before the flecainide test were independent predictors of successful hybrid therapy. In patients with paroxysmal AF without documented spontaneous AFL, the long‐term efficacy of hybrid therapy was 38.5% (P = 0.03). The flecainide infusion test reliably detects candidates for hybrid therapy. The efficacy of this therapy is maintained over the long‐term with a high patient compliance.
Arrhythmia Risk Prediction in Idiopathic Dilated Cardiomyopathy Based on Heart Rate Variability and Baroreflex Sensitivity
Authors: GRIMM WOLFRAM , CHRIST MICHAEL , SHARKOVA JULIA , MAISCH BERNHARD
Published: January 2005

This study examined the relation between heart rate variability (HRV) and baroreflex sensitivity (BRS) and subsequent major arrhythmic events (MAE), defined as sustained VT, VF or sudden death, in 263 patients with idiopathic dilated cardiomyopathy (IDC) in sinus rhythm. The predefined measure of HRV was the standard deviation of all normal‐to‐normal RR intervals (SDNN) on baseline 24‐hour ambulatory ECG. BRS was determined by the phenylephrine method. Over 52 ± 21 months of follow‐up, MAE occurred in 38 patients (14%). SDNN at baseline 24‐hour ambulatory ECG (106 ± 46 vs 109 ± 45, ns) and BRS (7.9 ± 5.5 vs 7.7 ± 5.3 ms/mmHg, ns) were both similar in patients with versus without MAE during follow‐up. In contrast, left ventricular ejection fraction was significantly lower in patients with versus without MAE (24%± 7% vs 31%± 10%, P < 0.019. Conclusions: Neither HRV nor BRS predicted MAE in patients with IDC.
Left Ventricular Functional Recovery During Cardiac Resynchronization Therapy:
Authors: CAPASSO FABIO , GIUNTA ANNA , STABILE GIUSEPPE , TURCO PIETRO , LA ROCCA VINCENZO , GRIMALDI GABRIELLA , DE SIMONE ANTONIO
Published: January 2005

Cardiac resynchronization therapy (CRT) improves myocardial performance in patients with heart failure (HF) and left bundle‐branch block (LBBB). Tissue Doppler echocardiography (TDE) has already been used to guide the selection of candidates for CRT. The objective of this study is to correlate the effects of CRT on left ventricular (LV) systolic function with wall motion synchrony assessed by TDE. High frame TDE data were obtained in 15 patients (mean age = 68.9 years, 11 men) with LBBB (QRS = 163 ± 13 ms) to derive temporal intraventricular horizontal asynchrony indexes, expressed as the time difference at the onset of shortening between the septum and the lateral (S‐L) and antero‐inferior (A‐I) walls, and measure the amount of delayed longitudinal contraction (DLC) within the LV. All measurements were made at baseline, 24 hours after implantation, and at 1 year of follow‐up. The results show that LV ejection fraction (EF) increased from 25 ± 6.2% at baseline to 36.9 ± 7.9% at 1 year, and was strongly related to DLC, expressed either by time duration (DLCd, r =−0.51; P < 0.0001) or percent of the basal segments (%DLC, r =−0.50; P < 0.001). New York Heart Association functional class, which decreased from 3.6 ± 0.5 to 2.3 ± 0.8, was correlated with %DLC (r = 0.50) and DLCd (r = 0.48, P < 0.001). Weaker correlations were found between LVEF and S‐Li (r =−0.40) and between NYHA and S‐Li (r = 0.40). It is concluded that DLC was the best among intraventricular asynchrony indexes in predicting increases in LVEF after CRT. DLC may be useful to identify responders to CRT.
Impact of Age and Basic Heart Rate on Heart Rate Turbulence in Healthy Persons
Authors: SCHWAB JÖRG OTTO , EICHNER GERRIT , SHLEVKOV NIKOLAY , SCHRICKEL JAN , YANG ALEXANDER , BALTA OSMAN , LEWALTER THORSTEN , LÜDERITZ BERNDT
Published: January 2005

Postextrasystolic acceleration of heart rate (HR), known as HR turbulence (HRT) is attenuated in patients with coronary artery disease at increased risk of adverse events. The influence of age and basic HR on HRT have not been evaluated in a large cohort of persons. In 95 healthy individuals, HRT onset (TO) and slope (TS) were calculated from 24‐hour ambulatory electrocardiograms, as well as the turbulence timing (TT). Gender specific differences in TO and TS were compared in simple, linear, weighted regression model. The influence of age and the basic HR preceding ventricular premature contractions on HRT were examined. We found that, in men and women, TO decreases as basic HR increases (P < 0.01). In contrast, in men, TS decreased as basic HR increases, whereas in women, basic HR influenced TS only slightly (P < 0.01). A multiple, linear regression model revealed a decrease in HRT with increasing age in men. In conclusion, physiological acceleration of the HR within the first 11 beats after premature ventricular complex (VPC) was observed in >75% of healthy individuals. An accelerating HR preceding the VPC influenced HRT in men. An increasing age was associated with a decrease in HRT in men and a decrease in TO in women. These results illustrate the importance of physiological modulations of HRT when used for risk stratification, especially in older populations.
Use of Physiologic Pacing After the Canadian Trial of Physiologic Pacing
Authors: TYERS G. FRANK O. , GAO MIN , HAYDEN ROBERT I. , LEATHER RICHARD , ASHTON THOMAS , KIELY MICHAEL
Published: January 2005

The Canadian trial of physiologic pacing (CTOPP), published in 2000, demonstrated a reduction in atrial fibrillation (AF), stroke and death with preservation of atrioventricular synchrony, though only the lower rate of AF was statistically significant. The purpose of this study was to determine the effect of CTOPP on pacing mode selection in our region. The British Columbia Cardiac Registry contains prospectively entered data covering a population of 4 millions (M) and 17 implanting centers. It was examined for mode selection trends from 1997 to 2002. At examination, there were data on 22,446 pulse generators (PG) and 29,898 leads. New implant rates per M population were 1997:473; 1998:456; 1999:505; 2000:513; 2001:486; 2002:510. PG replacements also increased, resulting in a total implant rate of 667 PG per M in 2002. Over the 6‐year period, DDD use decreased from 321 to 306, but DDDR use, more than doubled from 317 to 750 PG/year. VVI use steadily decreased from 741 to 410 PG/year, while VVIR use increased more modestly from 1997 to 1999, then remained stable. During the 6‐year period bracketing CTOPP, use of modes maintaining AV synchrony increased by over 32%, to 53% of PG implanted in 2002. Our PG implant rate was much higher than expected from prior retrospective surveys, and similar to rates in Belgium, France, and Germany. CTOPP did not decrease our use of physiologic pacing but, instead, was associated with a brief pause, then progressively increased in both academic and community centers. Patients' need and widely accepted standards of care proved more important in clinical decision making than the results of a flawed randomized trial.
Blood Pressure Response to Transition from Supine to Standing Posture Using an Orthostatic Response Algorithm
Authors: TSE HUNG‐FAT , SIU CHUNG‐WAH , TSANG VELLA , YU CANNAS , PARK EULJOON , BORNZIN GENE A. , BENSER MICHAEL E. , LAU CHU‐PAK
Published: January 2005

Upon standing from a supine position, the normal response is an increase in heart rate to maintain blood pressure (BP). In patients with chronotropic incompetence, heart rate may not increase upon standing, and they may experience orthostatic hypotension (OH). We evaluated a new orthostatic response (OSR) pacing algorithm that uses an accelerometer signal to detect sudden activity following prolonged rest to trigger a 2 minutes increase in pacing rate to 94 bpm. Ten recipients of DDDR pacemakers which contain the OSR compensation algorithm (mean age = 77 ± 9 years, 8 women) with sick sinus syndrome (n = 6) or atrioventricular block (n = 4) were studied. In all patients BP was measured before and 0.5, 1, 1.5, 2, and 3 minutes after standing at their programmed base rate. A 20 mmHg fall in systolic BP upon standing was observed in five patients (OH patients), while the other five were considered non‐OH patients. The measurements were repeated with the OSR algorithm turned on. Mean BP was defined as 1/3 systolic BP + 2/3 diastolic BP. Baseline heart rate was significantly slower in OH patients (62 ± 2 bpm) than non‐OH patients (71 ± 7 bpm, P < 0.05). In OH patients mean BP increased significantly upon standing (P < 0.05 for all comparisons) with the algorithm ON instead of decreasing with the algorithm OFF, at 1 minute (+3.4 vs −10.3 mmHg), 1.5 minutes (+7.0 vs −4.9 mmHg), 2 minutes (+1.6 vs −6.7 mmHg), and 3 minutes (+2.5 vs −8.5 mmHg). These preliminary results suggest that the OSR algorithm maintains BP upon standing in patients with OH.
High‐Density Circumferential Pulmonary Vein Mapping with a 20‐Pole Expandable Circular Mapping Catheter
Authors: HSU LI‐FERN , JAÏS PIERRE , HOCINI MÉLÈZE , SANDERS PRASHANTHAN , ROTTER MARTIN , TAKAHASHI YOSHIHIDE , SCAVÉE CHRISTOPHE , SACHER FREDERIC , CLÉMENTY JACQUES , HAÏSSAGUERRE MICHEL
Published: January 2005

The differentiation of pulmonary vein (PV) electrograms from atrial far‐field signals during PV isolation (PVI) for atrial fibrillation (AF) may be difficult. In addition, owing to highly variable PV ostial sizes, current fixed‐diameter circular PV mapping catheters may not yield optimal electrograms. We evaluated an expandable, circular 15–25 mm diameter, 20‐pole mapping catheter for PV mapping during sustained AF in 25 patients. After selective PV angiography to define the ostial position and size, the catheter was introduced into each PV and withdrawn to the most stable proximal position, with optimal wall contact ensured by progressive loop expansion. At each PV ostium, electrograms recorded at high resolution (HR) were compared with those recorded at a resolution similar to that of a standard 10‐pole Lasso catheter. After PVI performed during ongoing AF, the presence of residual far‐field potentials (FFP) under both set‐ups was compared. We mapped 97 PV, including 4 pairs with common ostia. In the HR recordings, the PV potentials had greater amplitude (0.5 ± 0.1 vs 0.3 ± 0.1 mV, P = 0.001) and fragmentation, whereas left atrial FFP were minimized. After successful isolation of all PV, FFP were observed in 33% of left superior and 28% of left inferior PV on the HR recordings, compared to 66% and 61%, respectively under normal resolution. Catheter stability and optimal wall contact, in combination with HR electrograms can optimize circumferential PV mapping during AF and improve the discrimination of FFP postablation.
Use of a New Non‐Fluoroscopic Three‐Dimensional Mapping System in Type I Atrial Flutter Ablation
Authors: VERBEET THIERRY , CASTRO JOSÉ , MORISSENS MARIELLE , NGOC EMMANUEL T. , DECOODT PIERRE
Published: January 2005

We studied 40 patients who underwent cavo‐tricuspid isthmus ablation for typical counterclockwise atrial flutter with cooled tip catheters between 2001 and 2003. Complete bi‐directional isthmus block was created in all patients. A new, three‐dimensional (3D), non‐fluoroscopic mapping system was used in 20 patients (test group), and conventional fluoroscopy in 20 others (conventional group), using anatomic and electrophysiologic criteria in both groups. We measured the total procedure, ablation procedure, and overall fluoroscopy times, and the total number of radiofrequency (RF) applications delivered in the two groups. The overall fluoroscopy time was shorter in the test group (mean 8.8 minutes, range 2–17 minutes) than the conventional group (29.7 minutes, range 12–57 minutes; P < 0.001). Though the overall procedure time was similar in both groups (92.5 ± 28.6 minutes vs 106.5 ± 20.9 minutes; P = 0.067) the ablation duration (25.1 ± 6.6 minutes versus 43.3 ± 19.6 minutes; P = 0.0051) and the total RF applications (10.6 ± 9.4 versus 16.4 ± 9.4; P = 0.044) were smaller in the test group. The use of a new, 3D non‐fluoroscopic mapping system markedly reduced the fluoroscopy exposure during typical atrial flutter ablation. It was also associated with a significant reduction in ablation time and in the number of RF applications. Since atrial flutter ablation is one of the most frequently performed procedures, this system may significantly reduce the overall amount of radiation exposure in high‐volume laboratories.
Effects of Systolic Atrial Function on Plasma Renin Activity and Natriuretic Peptide Secretion after High Rate Atrial and Ventricular Pacing in Dogs
Authors: ZUPAN IGOR , KRHIN BLAŽ , BRESKVAR URŠKA , P. ZUPAN IRENA , RAKOVEC PETER
Published: January 2005

Rapid atrial rates cause electrical, structural remodeling, and neuro‐humoral changes. This study compares the effects of mechanical remodeling on plasma renin activity (PRA) and atrial natriuretic peptide (ANP) secretion. Eight beagles were subjected to rapid atrial pacing (AP) at 400 beats/min for 16 days. After complete recovery of left ventricular function, they underwent rapid ventricular pacing (VP) at 240 beats/min of equal duration. Left atrial systolic maximal dimension (LAmax) and left atrial appendage (LAA) peak late emptying velocity (LAA‐E) were assessed by echocardiography. Blood samples were taken from the right atrium and from the peripheral vein. LAmax after AP and VP enlarged significantly (2.16 ± 0.21 cm vs 2.41 ± 0.23 cm, P = 0.002). Compared with baseline, LAA‐E velocities were significantly reduced (0.65 ± 0.12 m/s vs 0.26 ± 0.16 m/s, P = 0.001) after AP only. AP caused a significant elevation of PRA in right atrial (9.28 ± 4.23 nmol/L per hour) and peripheral samples compared with baseline values (4.82 ± 2.53 nmol/L per hour, P = 0.04). ANP levels increased after AP (1117.12 ± 252.21 fmol/L) with respect to baseline values (824.37 ± 159.08 fmol/L, P = 0.001). There was no difference in PRA and ANP levels between atrial and peripheral samples. Atrial size and impaired systolic appendage function play an important role in secretion of PRA and ANP. Both neuro‐humoral pathways may be therapeutic targets in the treatment of patients with AF.
Detection of Atrial Fibrillation by Implanted Devices with Wireless Data Transmission Capability
Authors: VARMA NIRAJ , STAMBLER BRUCE , CHUN SUNG
Published: January 2005

Remote telemetry may facilitate the management of implantable devices. We tested the reliability of a new automatic, wireless home monitoring (HM) system that archives data every 24 hours. We retrospectively analyzed archival data from 276 consecutive pacing system implants to define temporal atrial fibrillation (AF) patterns and associated ventricular rate. An “AF day” was defined by a >20%/24 hour mode switch (MS) duration, irrespective of the MS number. Management decisions resulting from transmissions were noted. A pilot study confirmed that 89% of 22,356 transmissions were successful, of which >90% were received in <5 minutes. Data integrity was 100% preserved. Overall, AF developed in 29 patients (10.5%), representing a total of 645 AF days (mean = 22.2 ± 29.6 AF, median = 9 days), over 12 ± 2 months of monitoring. AF was infrequent (50% of 24 hours. Ventricular rates during 645 AF days in 29 patients averaged 95.1 ± 9.9 beats/min (median = 94 beats/min). Ventricular rates were >80 beats/min in 25 ± 30 AF days (median = 11 days). HM enabled rapid anticoagulation decisions. In recipients of implantable devices, automatic wireless telemetry with HM was efficient and reliable. Its application may overcome some current challenges in AF management by early notification and precise measurement of both AF burden and ventricular rate during AF.
A New Endocardial “Over‐the‐Wire” or Stylet‐Driven Left Ventricular Lead:
Authors: ELLERY SUE , PAUL VINCE , PRENNER GUENTHER , TSCHELIESSNIGG KARLHEINZ , MERKELY BELA , MALINOWSKI KLAUS , FRÖHLIG GERD , HINTRINGER FLORIAN , BOSSE OLAF , DIOTALLEVI PAOLO , RAVAZZI ANTONIO P. , FLATHMANN HORST , DANILOVIC DEJAN , UNTERBERG‐BUCHWALD CHRISTINA ,   OVID STUDY INVESTIGATORS
Published: January 2005

Transvenous left ventricular (LV) leads are primarily inserted “over‐the‐wire” (OTW). However, a stylet‐driven (SD) approach may be a helpful alternative. A new polyurethane‐coated, unipolar LV lead can be placed either by a stylet or a guide wire, which can be inserted into the lead body from both ends. The multicenter OVID study evaluates the clinical performance of this new steroid‐ and nonsteroid eluting lead. The primary endpoint is the LV lead implant success rate after identification of the coronary sinus (CS). Secondary endpoints include complication rate, short‐ and long‐term lead characteristics, overall procedure and LV lead placement duration, total fluoroscopy time, and lead handling characteristics ratings. To date, 96 patients with heart failure (68 ± 9 years old, 76% men) are enrolled. The CS was identified in 95 patients and, in 85 (88.5%), the LV lead was successfully implanted. The final lead positioning was lateral in 41%, posterolateral in 35%, anterolateral in 18%, and great cardiac vein in 6% of patients. In 70%, the 85 successful implantations, both stylet‐driven and guide‐wire techniques were used, a stylet only was used in 22%, and a guide wire only in 8%. Mean overall duration of 85 successful procedures was 112 ± 40 minutes, total fluoroscopy time 28 ± 15 minutes, and the duration of LV lead placement was 35 ± 29 minutes. During a 3‐month follow‐up, the loss of LV capture occurred in three and phrenic nerve stimulation in six patients. The mean long‐term pacing threshold is 0.8 V/0.5 ms and pacing impedance is 550 Ω. The OVID data suggest that these new leads are safe and effective. The choice of both OTW and SD techniques during lead implantation offers greater procedural flexibility.
Influence of Different Atrioventricular and Interventricular Delays on Cardiac Output During Cardiac Resynchronization Therapy
Authors: RIEDLBAUCHOVÁ LUCIE , KAUTZNER JOSEF , FRÍDL PETR
Published: January 2005

Restoration of the atrioventricular (AVD) and interventricular (VVD) delays increases the hemodynamic benefit conferred by biventricular (BiV) stimulation. This study compared the effects of different AVD and VVD on cardiac output (CO) during three stimulation modes: BiV‐LV = left ventricle (LV) preceding right ventricle (RV) by 4 ms; BiV‐RV = RV preceding LV by 4 ms; LVP = single‐site LV pacing. We studied 19 patients with chronic heart failure due to ischemic or idiopathic dilated cardiomyopathy, QRS ≥ 150 ms, mean LV end‐diastolic diameter = 78 ± 7 mm, and mean LV ejection fraction = 21 ± 3%. CO was estimated by Doppler echocardiographic velocity time integral formula with sample volume placed in the LV outflow tract. Sets of sensed‐AVDs (S‐AVD) 90–160 ms, paced‐AVDs (P‐AVD) 120–160 ms, and VVDs 4–20 ms were used. BiV‐RV resulted in lower CO than BiV‐LV. S‐AVD 120 ms and P‐AVD 140 ms caused the most significant increase in CO for all three pacing modes. LVP produced a similar increase in CO as BiV stimulation; however, AV sequential pacing was associated with a nonsignificantly higher CO during LVP than with BiV stimulation. CO during BiV stimulation was the highest when LV preceded RV, and VVD ranged between 4 and 12 ms. The most negative effect on CO was observed when RV preceded LV by 4 ms. Hemodynamic improvement during BiV stimulation was dependent both on optimized AVD and VVD. LV preceding RV by 4–12 ms was the most optimal. Advancement of the RV was not beneficial in the majority of patients.
Effect of Short Pulse Width Programming in AutoCapture Devices
Authors: KOK LAI CHOW , HANNA GEORGE P. , BROWNSTEIN SHELDON , KIM MICHAEL , LEVINE PAUL A. , VIJAYARAMAN PUGAZHENDHI , GO ANDRE , SYED ZAFFER A.
Published: January 2005

Pacing chronaxie can increase over time. The impact of a short pulse duration on threshold (THR) variations, frequency of noncapture episodes, and overall patient safety has not been fully studied. AutoCapture (AC) pacemakers are capable of memorizing THR trends and loss of capture (LOC) episodes. The study included 20 recipients of AC pacemakers (mean age = 76 ± 9 years, 15 men) followed for 6 months. They were randomly assigned to pulse durations of 0.2 versus 1.0 ms at 1 month, and crossed over to the alternate programming at 3 months. Evoked response (ER) and AC tests were performed at follow‐up. At 0.2 ms and 1.0 ms, the mean number of LOC/day was 2.37 ± 5.81 and 0.91 ± 0.49, respectively (ns). LOC trends between follow‐up were significantly different with 0.2 versus 1.0 ms pulse duration (P < 0.01). AC THR at 1.0 ms was significantly lower (0.44 ± 0.77) than at 2.0 ms (0.97 ± 0.26, P < 0.05). No patient reported symptoms related to LOC during the study. Pulse duration programmed near the strength‐duration curve is associated with greater variations in THR and LOC. AC responds to these changes by delivering 4.5 V pulses and keeping the capture THR at low, though safe values.
Incidence and Predictive Factors of Atrial Fibrillation in Paced Patients
Authors: PIOGER GUY , JAUVERT GAEL , NITZSCHÉ RÉMI , POZZAN JOELLE , HENRY LAURE , ZIGELMAN MICHEL , LENY GÉRARD , VANDRELL MARIE‐CHRISTINE , RITTER PHILIPPE , CAZEAU SERGE
Published: January 2005

We have designed a prospective observational study to analyze the incidence and predictive factors of atrial fibrillation (AF) during a long follow‐up, in a large population. Atrial fibrillation episodes were documented by the fallback mode switch (FMS) provided by implanted pacemakers. We have included 377 patients (61% men). The pacing indications were atrioventricular (AV) block (49%), sinus node disease (SND, 16%), bradycardia‐tachycardia syndrome (BTS, 5%), AV block + SND (19%), AV block + BTS (6%), and BTS + SND (5%). The mean age at implant was 75 ± 12 (range 28–95). Atrial fibrillation before inclusion was documented in 10% of patients. Drug therapy at first follow‐up included beta‐adrenergic blockers (17% of the patients), amiodarone (13%), and others (16%). The mean follow‐up was 30 ± 24 weeks. At least one AF episode was stored during follow‐up in the memory of 169 pacemakers (45%). Among patients without history of AF at implant, 46% had documented FMS during follow‐up. Patients with AF received more antiplatelet medications than patients without AF (P = 0.03). In patients with AF, New York Heart Association functional class was slightly higher, amiodarone and sotalol were more often prescribed, and the proportion of hypertension was higher than in patients without AF. However, these trends were not statistically significant. A significant higher incidence of premature atrial beats was observed in patients with AF than patients without AF (P < 0.0002). Patients with AF had a lower atrial percentage of paced events (55%) than patients without AF (63%, P < 0.02). These preliminary results confirm the high incidence of AF in paced patients and suggest a preventive effect of atrial pacing. The effects of other clinical variables may be confirmed with a longer follow‐up in a larger population.
Performance of a New Cardiac Cryoablation System in the Treatment of Cavotricuspid Valve Isthmus‐Dependent Atrial Flutter
Authors: DAUBERT JAMES P. , HOYT ROBERT H. , JOHN ROY , CHINITZ LARRY , MARTIN DAVID T. , FELLOWS CHRISTOPHER , FELD GREGORY , PELKEY WILLIAM , SEHRA RUCHIR ,   CryoCor Atrial Flutter Investigators
Published: January 2005

We sought to evaluate prospectively the safety and efficacy of cryothermal energy to ablate typical atrial flutter (AFL). Ablation of cardiac tissue using cryothermal energy has recently been developed as an alternative to radiofrequency energy, which may offer certain advantages in the treatment of AFL. This prospective, multicenter nonrandomized study of a new catheter‐based system for the treatment of cavotricuspid isthmus (CTI)‐dependent AFL enrolled patients between 18 and 75 years of age. The CTI dependence of AFL was confirmed at electrophysiologic study with activation mapping and/or entrainment. Patients with atrial septal defect, recent myocardial infarction, left ventricular ejection fraction <0.30, or prior AFL ablation were excluded. Cryoablation of AFL was performed in 48 patients from 11 centers. The procedure was immediately successful in 45 patients (94%), and effective in 30 of 40 patients with complete data available at 6 months. Cryoablation is a promising new treatment of CTI‐dependent AFL refractory to medical therapy. Further improvements in catheter design and intravascular sheaths will be tested in a larger multicenter trial.
A New Dual‐Chamber Pacing Mode to Minimize Ventricular Pacing
Authors: SAVOURÉ ARNAUD , FRÖHLIG GERD , GALLEY DANIEL , DEFAYE PASCAL , REUTER SYLVAIN , MABO PHILIPPE , SADOUL NICOLAS , AMBLARD AMEL , LIMOUSIN MARCEL , ANSELME FREDERIC
Published: January 2005

Despite the low long‐term incidence of high‐degree atrioventricular (AV) block and the known negative effects of ventricular pacing, programming of the AAI mode in patients with sinus node dysfunction (SND) remains exceptional. A new pacing mode was, therefore, designed to combine the advantages of AAI with the safety of DDD pacing. AAIsafeR behaves like the AAI mode in absence of AV block. First‐ and second‐degree AV blocks are tolerated up to a predetermined, programmable limit, and conversion to DDD takes place in case of high‐degree AV block. From DDD, the device may switch back to AAI, provided AV conduction has returned. The safety of AAIsafeR was examined in 43 recipients (70 ± 12‐year old, 24 men) of dual chamber pacemakers implanted for SND or paroxysmal AV block. All patients underwent 24‐hour ambulatory electrocardiographic recordings before hospital discharge and at 1 month of follow‐up with the AAIsafeR mode activated. No AAIsafeR‐related adverse event was observed. At 1 month, the device was functioning in AAIsafeR in 28 patients (65%), and the mean rate of ventricular pacing was 0.2%± 0.4%. Appropriate switches to DDD occurred in 15 patients (35%) for frequent, unexpected AV block. AAIsafeR mode was safe and preserved ventricular function during paroxysmal AV block, while maintaining a very low rate of ventricular pacing. The performance of this new pacing mode in the prevention of atrial fibrillation will be examined in a large, controlled study.
Clinical Testing of a New Pacemaker Function to Monitor Ventricular Capture
Authors: ALONSO CHRISTINE , SAVOURÉ ARNAUD , JAUVERT GAEL , CASSET CYRILLE , RANAIVOSON HANTA , CAZEAU SERGE , ANSELME FRÉDÉRIC
Published: January 2005

Automatic beat‐by‐beat capture functions are designed to minimize the pacing energy delivered, while maintaining the highest safety by delivering an immediate back‐up stimulus in case of loss of capture. The objective of this study was to estimate the lowering of ventricular pacing amplitude allowed by such a function, compared to amplitudes usually set manually in routine practice. An automatic ventricular pacing threshold test is launched every 6 hours to measure the automatic capture threshold (AT). From AT the function calculates: (1) the“capture amplitude”(Vc) = AT + 0.5 V at a minimum output of 1 V and (2) the“safety amplitude” (Vs) = twice AT at a minimum output of 2.5 V. The function preferentially uses Vc and verifies capture after each paced beat. In case of loss of capture, a back‐up spike is delivered and Vs is implemented until the next threshold measurement. We estimated the ventricular amplitude delivered by the pacemaker from data stored in the pacemaker memory. We compared these values with the pacing amplitude typically programmed manually (MPA) by physicians at twice AT and a minimum of 2.5 V. Data from 57 recipients of Talent 3 DR pacemakers were analyzed. Complete data sets were available in 25 patients at 1 day, 28 at 1 month, and 39 between 1 day and 1 month. No loss of capture or ventricular pause was observed on 53 ambulatory electrocardiograms (ECG); and pulse amplitude automatically delivered by the device was significantly lower than the MPA at each of the three time points analyzed. This new beat‐by‐beat capture function allows a significant lowering of the pacing amplitude compared to manual settings, while preserving a 100% safety.
An Algorithm for Verifying Biventricular Capture Based on Evoked‐Response Morphology
Authors: DIOTALLEVI PAOLO , RAVAZZI PIER ANTONIO , GOSTOLI ENRICO , DE MARCHI GIUSEPPE , MILITELLO CARMELO , KRAETSCHMER HANNES
Published: January 2005

Cardiac resynchronization therapy relies on consistent beat‐by‐beat myocardial capture in both ventricles. A pacemaker ensuring right (RV) and left ventricular (LV) capture through reliable capture verification and automatic output adjustment would contribute to patients' safety and quality of life. We studied the feasibility of an algorithm based on evoked‐response (ER) morphology for capture verification in both the ventricles. RV and LV ER signals were recorded in 20 patients (mean age 72.5 years, range 64.3–80.4 years, 4 females and 16 males) during implantation of biventricular (BiV) pacing systems. Leads of several manufacturers were tested. Pacing and intracardiac electrogram (IEGM) recording were performed using an external pulse generator. IEGM and surface‐lead electrocardiogram (ECG) signals were recorded under different pacing conditions for 10 seconds each: RV pacing only, LV pacing only, and BiV pacing with several interventricular delays. Based on morphology characteristics, ERs were classified manually for capture and failure to capture, and the validity of the classification was assessed by reference to the ECG. A total of 3,401 LV‐ and 3,345 RV‐paced events were examined. In the RV and LV, the sensitivities of the algorithm were 95.6% and 96.1% in the RV and LV, respectively, and the corresponding specificities were 91.4% and 95.2%, respectively. The lower sensitivity in the RV was attributed to signal blanking in both channels during BiV pacing with a nonzero interventricular delay. The analysis revealed that the algorithm for identifying capture and failure to capture based on the ER‐signal morphology was safe and effective in each ventricle with all leads tested in the study.
Cardiac Safety of Neuromuscular Incapacitating Defensive Devices
Authors: McDANIEL WAYNE C. , STRATBUCKER ROBERT A. , NERHEIM MAX , BREWER JAMES E.
Published: January 2005

Neuromuscular incapacitation (NMI) devices discharge a pulsed dose of electrical energy to cause muscle contraction and pain. Field data suggest electrical NMI devices present an extremely low risk of injury. One risk of delivering electricity to a human is the induction of ventricular fibrillation (VF). We hypothesized that inducing VF would require a significantly greater NMI discharge than a discharge output by fielded devices. The cardiac safety of NMI discharges was studied in nine pigs weighing 60 ± 28 kg. The minimum fibrillating level was defined as the lowest discharge that induced VF at least once, the maximum safe level was defined as the highest discharge which could be applied five times without VF induction, and the VF threshold was defined as their average. A safety index was defined as the ratio of the VF threshold to the standard discharge level output by fielded NMI devices. A VF induction protocol was applied to each pig to estimate the VF threshold and safety index. The safety index for stored charge ranged from 15X to 42X as weight increased from 30 to 117 kg (P < 0.001). Discharge levels above standard discharge and weight were independently significant for predicting VF inducibility. The safety index for an NMI discharge was significantly and positively associated with weight. Discharge levels for standard electrical NMI devices have an extremely low probability of inducing VF.