bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk factors associated with onychomycosis
Authors: Sigurgeirsson B , Steingrímsson Ó
Published: December 2003

Objective  To examine possible risk factors related to onychomycosis.

Background  Onychomycosis is a common disease with multifactorial aetiology, but little is known about the risk factors for this disease.

Patients and methods  Questions related to signs, symptoms and possible risk factors associated with onychomycosis were sent to 3992 persons aged 16 years and older selected randomly from the Icelandic National Registry. Patients with suspected onychomycosis, based on photographs, were offered mycological examination. Data from the questionnaire and the results of mycological examination were used to calculate the odds ratio (OR) for several factors that might be associated with onychomycosis.

Results  Two thousand four hundred and eighty‐six subjects responded to the questionnaire. Prevalence for mycologically determined onychomycosis was 11.1% in the Icelandic population. A history of the following factors more than doubled the risk of onychomycosis: cancer (OR 3.44; 95% CI 1.15–10.35), psoriasis (OR 2.44; 95% CI 1.61–3.72), tinea pedis interdigitalis (OR 3.93; 95% CI 3.11–4.95), the moccasin form of tinea pedis (OR 4.26; 94% CI 3.34–5.45), parents with onychomycosis (OR 2.59; 95% CI 1.89–3.53), children with onychomycosis (OR 3.48; 95% CI 2.05–5.88), spouse with onychomycosis (OR 2.53; 95% CI 1.72–3.72), regular swimming activity (OR 2.57; 95% CI 2.00–3.30) and age 50 years or older (OR 2.74; 95% CI 2.19–3.42).

Conclusions  Several risk factors are associated with onychomycosis. Knowledge of these risk factors is important when treating and educating patients with onychomycosis.
Two cases of squamous cell carcinoma treated with topical imiquimod 5%
Authors: Oster‐Schmidt C
Published: December 2003

We report the first two cases of squamous cell carcinoma successfully treated with imiquimod 5% cream as a monotherapy. Imiquimod is a new immunomodulating drug that is registered for genital HPV infection but has also shown good efficacy in several cutaneous malignancies.
Nailfold digital capillaroscopy in 447 patients with connective tissue disease and Raynaud's disease
Authors: Nagy Z , Czirják L
Published: December 2003

The presence of megacapillaries and a decreased capillary density are the hallmarks of the scleroderma capillary pattern, which can be detected by nailfold capillarmicroscopy. One hundred and eighty‐six patients with Raynaud's phenomenon, 65 cases with undifferentiated connective tissue disease (UCTD), 47 patients with systemic lupus erythematosus (SLE), 26 patients with dermato/polymyositis, 14 with rheumatoid arthritis, seven cases with primary Sjögren's syndrome and 102 patients with systemic sclerosis (SSc) were investigated. Of the 16 patients with diffuse cutaneous SSc and the 86 limited cutaneous SSc cases, 14 (87.5%) and 53 (61.6%) showed the scleroderma capillary pattern, respectively. Nine of the 65 (13.8%) cases with UCTD and 24 of the 186 (12.9%) cases with Raynaud's phenomenon also exhibited the same pattern. Four of the 47 (8.5%) with SLE and seven of the 26 (26.9%) with dermato/polymyositis, and no patients with rheumatoid arthritis or Sjögren's syndrome, exhibited the scleroderma capillary pattern. The conclusion is that the scleroderma capillary pattern is often present in SSc and dermato/polymyositis. Furthermore, patients with Raynaud's phenomenon and UCTD may also occasionally exhibit this pattern. Therefore, capillarmicroscopy seems to be a useful tool for the early selection of those patients who are potential candidates for developing scleroderma spectrum disorders.
Antifungal activity of Thymus oils and their major compounds
Authors: Pina‐Vaz C , Gonçalves Rodrigues A , Pinto E , Costa‐de‐Oliveira S , Tavares C , Salgueiro L , Cavaleiro C , Gonçalves MJ , Martinez‐de‐Oliveira J
Published: December 2003

The increasing recognition and importance of fungal infections, the difficulties encountered in their treatment and the increase in resistance to antifungals have stimulated the search for therapeutic alternatives. Essential oils have been used empirically. The essential oils of Thymus (Thymus vulgaris, T. zygis subspecies zygis and T. mastichina subspecies mastichina) have often been used in folk medicine. The aim of the present study was to evaluate objectively the antifungal activity of Thymus oils according to classical bacteriological methodologies − determination of the minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) − as well as flow cytometric evaluation. The effect of essential oils upon germ tube formation, an important virulence factor, was also studied. The mechanism of action was studied by flow cytometry, after staining with propidium iodide. The chemical composition of the essential oils was investigated by gas chromatography (GC) and gas chromatography/mass spectroscopy (GC/MS). The antifungal activity of the major components (carvacrol, thymol, p‐cymene and 1,8‐cineole) and also possible interactions between them were also investigated. The essential oils of T. vulgaris and T. zygis showed similar antifungal activity, which was greater than T. mastichina. MIC and MLC values were similar for all the compounds tested. At MIC values of the essential oils, propidium iodide rapidly penetrated the majority of the yeast cells, indicating that the fungicidal effect resulted primarily from an extensive lesion of the cell membrane. Concentrations below the MIC values significantly inhibited germ tube formation. This study describes the potent antifungal activity of the essential oils of Thymus on Candida spp., warranting future therapeutical trials on mucocutaneous candidosis.
Mycoplasma genitalium: the aetiological agent of urethritis and other sexually transmitted diseases
Authors: Jensen Jørgen Skov
Published: December 2003

Mycoplasma genitalium was first isolated in 1980 from two of 13 men with non‐gonococcal urethritis (NGU). It shares several features with M. pneumoniae, a recognized respiratory tract pathogen. It is extremely difficult to isolate by culture. The development of sensitive and specific polymerase chain reaction (PCR) assays in the early 1990s made clinical studies possible and a significant number of publications have shown a strong association between M. genitalium and NGU, independent of Chlamydia trachomatis. The purpose of this review is to evaluate the currently available information on the associations between M. genitalium and urogenital tract infections in men and women and assess their fulfilment of the Henle–Koch postulates. It is concluded that there is very strong evidence that M. genitalium is a cause of NGU in men and cervicitis in women. Evidence for upper genital tract infections in women has begun to accrue, but further studies are needed. The optimal treatment of M. genitalium infections remains to be determined, but antibiotics of the macrolide group appear to be more active than tetracyclines.
Alcohol abuse among adolescents: regional evidence from Spain
Authors: Duarte Rosa , Alberto Molina José
Published: December 2003

The aim of this paper is to offer regional evidence from Spain on alcohol abuse among adolescents. Specifically, we identify the determinants of the decision to abuse alcohol with respect to the five most important regions of Spain, as well as for the country as a whole. To this end, we estimate Probit specifications using data drawn from the Spanish Surveys on Drug Use in the School Population corresponding to 1994, 1996 and 1998. The results first reveal patterns that are qualitatively similar, but quantitatively different. Similarly, it would appear that economic policies aimed at reducing the access of adolescents to alcohol may have a positive effect on reducing abuse. Finally, the results suggest that encouragement be given to healthy habits among young people, as well as to the fight against education failure and the launching of information campaigns that accurately portray the current lifestyle of adolescents.
UK food shopping in the 1950s: the social context of customer loyalty
Authors: Lyon Phil , Colquhoun Anne , Kinney Dave
Published: December 2003

Food shopping – although often dismissed as dreary necessity – has always served a range of latent functions. In the 1950s, food storage limitations and tight budgets gave rise to weekly – often daily – shopping patterns that also allowed shoppers to meet certain social needs. Going to food shops, and the way that customer service was organized, produced significant interactional opportunities which were valued by participants. Exchanging news with other customers may have reinforced shopping patterns but shopkeepers, and knowledgeable assistants, were also useful intermediaries for product and usage information. Functional specialization in food commodities bestowed the aura of expertise, and direct accountability for the quality of what was sold provided a more personal style of retailing than is currently typical. Much depended on the perception of relationships. The 1950s were an important transitional period in the UK. Rationing gave way to wider choice and availability, while the market position of corner shops was increasingly eclipsed by town centre supermarkets. This article explores the social context of food shopping, and its relationship to the specific issue of customer loyalty.
Fathoming tropical biodiversity: the continuing discovery of Neotropical mammals
Authors: Patterson Bruce D.
Published: December 2003

We are still far from knowing, even approximately, the number of extant mammal species. Successive attempts over the last half‐century to tally mammals of the world have produced a steadily (or perhaps exponentially) climbing total. By analysing nomenclature for Neotropical mammals, two well‐defined biases are documented that are associated with species accumulation. First, definite trends in body size are evident, so that larger organisms were more quickly apparent to systematists. Most species being described today are small‐bodied forms. Secondly, the locus of descriptive taxonomic work on this fauna has clearly shiftedseriatimfrom continental European scientists and institutions, through British and American counterparts, to Latin American institutions. Although specifying these and other biases might focus models of species accumulation, there are no real short cuts in the global effort to inventory and document biological diversity.
Control of the Whitefly Trialeurodes vaporariorum Westw.  (Homoptera, Aleyrodidae) on tomato by the new insecticide Acetamiprid
Authors: Zabel Anton , Manojlovic Bozidar , Stankovic Sladjan , Rajkovic Snezana , Kostic Miroslav
Published: December 2003

The efficacy of a new class of insecticide (chloronicotinyl) Mospilan 20 SP (a. i. acetamiprid), compared with Lannate 90 SL (a. i. methomyl) and Applaud WP 25 (a. i. buprofezin), in glasshouse control of whitefly (Trialeurodes vaporariorum) on tomatoes, was investigated.  All investigated insecticides significantly decreased the number of whitefly larvae, compared with untreated plots where population density grew during the trial. Based on statistical analysis, efficacy of all insecticides on whitefly larvae were in the same category. Some differences occurred 7 days after the third treatment. Deposited egg number was significantly different between checks and each insecticide plot. Efficacy of investigated insecticides, evaluated according to deposited egg number, was also good and in the same category.
First report on the distribution of microsporidian infections of browntail moth (Euproctis chrysorrhoea L.) populations in Bulgaria*
Authors: Pilarska D. , Linde A. , Goertz D. , McManus M. , Solter L. , Bochev N. , Rajkova M.
Published: December 2003

The distribution of microsporidian infections of browntail moth (Euproctis chrysorrhoea L.) populations in Bulgaria was studied. Of the 72 browntail moth populations in the regions of Balkan, Sredna Gora, Sakar Mountains, and Rodope Mountains, 21 were infected by Microsporidia. The Microsporidia belong to two genera –Nosema (Dihaplophasea, Nosematidae) and Endoreticulatus (Haplophasea, Encephalitozoonidae). Microsporidial infections caused by a Nosema were found in 14 populations, by an Endoreticulatus in 8 populations, and mixed infections of Nosema and Endoreticulatus were recorded from 3 populations. Endoreticulatus was present in Balkan, Sredna Gora, and the Sakar Mountains. Nosema infections were found in Sakar Mountains and Rodope, and mixed infections were recorded only from the Sakar Mountain populations.
Bark beetle (Coleoptera, Scolytidae) outbreak and system of IPM measures in an area affected by intensive forest decline connected with honey fungus (Armillaria sp.)
Authors: Jakuš R.
Published: December 2003

The character of a bark beetle outbreak, planning system, and implementation of IPM measures in a forest affected by intensive decline connected with honey fungus (Armillaria sp.) is described.  It is possible to distinguish two levels of outbreak in the study area. The first level is characterized by spruce mortality connected with yellowing of spruce and presence of plant pathogens, mostly Armillaria sp. Forest stands have disperse infestations of bark beetles. Identification of infested trees and salvage cutting in time are problematic. In case of late processing of infested trees, the second level of outbreak could become manifest. The populations of bark beetle increase. Beetles could attack relatively healthy trees. The classical outbreak with forest edges and spot infestations starts. The identification of infested trees is easier. The application of pheromone trap barriers is effective. Thus, the second level of outbreak could be easily managed. The planning of IPM measures is concerned with localization of various pheromone trap systems in particular forest stands. It is based on field survey, data acquisition, estimation of swarming bark beetle population, and information of pheromone system effectiveness.
Isolation of heterorhabditid nematodes from palm tree planted areas and their implications in the Red Palm Weevil control1
Authors: Salama H. S. , Abd‐elgawad Mahfouz M.
Published: December 2003

Soil samples from 102 sites planted with intercropped palm trees in 8 Egyptian governorates were baited with greater wax moth larvae for the recovery of entomopathogenic nematodes. Only heterorhabditied nematodes were extracted from 5 sites in Alexandria, Behaira, Ismaelia, and Giza governorates. Evaluation of the novel isolates in the laboratory to identify the most efficient ones for biological control of the red palm weevil Rhynchophorus ferrugineus (Oliv.) showed that they are generally more virulent than other entomopathogenic nematode species. However, only two of the 5 strains, isolated from Behaira and Giza, survived a 24 h exposure period in palm weevil‐infested tree tissue with a low viability of 19 and 14 %, respectively.
Studies on insects causing galls on the leaves of pedunculate oak Quercus robur in southern Poland1,2
Authors: Skrzypczyńska Małgorzata
Published: December 2003

Analytical studies concerning the species composition of galls occurring on the leaves of Quercus robur L. were conducted in 2000 in three localities: near an urban agglomeration of Kraków – the Wolski Forest, in a protected area – the Ojców National Park and in a managed forest – the Andrychów Forest District. In each of the selected localities 2000 leaves (a total of 6000 leaves) were randomly collected. A total of 2246 galls, including 1028 in the Andrychhów FD, were found. The galls represented 12 insect species. The species composition of galls in the Ojców NP (11 species) distinctly differed from those of the remaining two areas (7 species each). Neuroterus quercusbaccarum (L.) ♀♀ was the most abundant species in the managed forest. The index of occurrence frequency and the Agrell’s index of species co‐existence have been calculated. The frequency of gall occurrence varied considerably in the investigated localities. On the basis of the Agrell’s index of species co‐existence it was shown that the strongest bond existed between Neuroterus laeviusculus Schenck ♀♀ and Andricus ostrea (Hartig) ♀♀ in the managed forest.
Efficiency of the mixed biocide GCSC‐BtA against vegetable pests  of different arthropod orders in the south‐eastern China1
Authors: Sengonca C. , Liu B. , Zhu Y. J.
Published: December 2003

The present paper deals with the efficiency of the mixed biocide GCSC‐BtA against vegetable pests of five orders of arthropod insects in the south‐eastern China, i. e., diamondback moth, Plutella xylostella (L.); green peach aphid, Myzus persicae (Sulzer); yellow‐fanded flea beetle, Phyllotreta vittata Fabricius; vegetable leaf miner, Phytomyza nigricornis Macquart; and vegetable spider mite, Tetranychus neocaledonicus Andre. The results show that the mixed biocide GCSC‐BtA has a higher efficacy of control against all of the five pests than the commercial biocide B.t. and insecticide Diazinon. GCSC‐BtA gave a higher mortality value of 92.18 % against P. xylostella as compared to the biocide B.t. with a value of 64.70 % and Diazinon with a value of 50.00 %. Similar mortalities were obtained with the other four pests regarding the efficacy of the three products tested against them.

The concentration‐mortality regression equations were calculated by the probit analysis, from which the average mortalities were calculated. The values calculated for GCSC‐BtA were 81.13 % for P. xylostella, 75 % for M. persicae and T. neocaledonicus, 69.23 % for P. vittata, and 61.03 % for P. nigricornis as compared to those caused by Diazinon: 33.33 %, 27.42 %, 66.31 %, 44.54 %, 19.65 % for P. xylostella, M. persicae, P. vittata, P. nigricornis, and T. neocaledonicus, respectively. Based on LC50, P. xylostella was most susceptible to GCSC‐BtA with a LC50 value of 0.3445, followed by B.t. with a value of 0.8404 and Diazinon with a value of 1.3160. The LC50 value of GCSC‐BtA for M. persicae was 0.4660 which was about three times less than that of Diazinon. LC50 value of GCSC‐BtA for P. vittata was 0.3954 which was about the same as that of Diazinon. P. nigricornis and T. neocaledonicus were also much more susceptible to GCSC‐BtA than to B.t. and Diazinon. It is concluded that GCSC‐BtA kills more target pests than B.t. and is more effective than Diazinon in controlling the vegetable pests.
The Effects of Interruptions, Task Complexity, and Information Presentation on Computer‐Supported Decision‐Making Performance
Authors: Speier Cheri , Vessey Iris , Valacich Joseph S.
Published: December 2003

Interruptions are a frequent occurrence in the work life of most decision makers. This paper investigated the influence of interruptions on different types of decision‐making tasks and the ability of information presentation formats, an aspect of information systems design, to alleviate them. Results from the experimental study indicate that interruptions facilitate performance on simple tasks, while inhibiting performance on more complex tasks. Interruptions also influenced the relationship between information presentation format and the type of task performed: spatial presentation formats were able to mitigate the effects of interruptions while symbolic formats were not. The paper presents a broad conceptualization of interruptions and interprets the ramifications of the experimental findings within this conceptualization to develop a program for future research.
The Strength‐Duration Relationship of Monophasic Waveforms with Varying Capacitance Sizes in External Defibrillation
Authors: YAMANOUCHI YOSHIO , BREWER JAMES E. , MOWREY KENT , MAZGALEV TODOR N. , WILKOFF BRUCE L. , TCHOU PATRICK J.
Published: December 2003

The shape of the shock waveform influences defibrillation efficacy. However, the optimal combination between capacitance size and truncation/tilt which can determine monophasic waveform's shape, has not been determined for external defibrillation. The purpose of this study was to assess the effects of varying capacitance and tilt on external defibrillation using exponential monophasic waveforms. In a pig model of external defibrillation (n = 10, 30 ± 6 kg), nine exponential monophasic waveforms combining three capacitance values (30 μF, 60 μF, and 120 μF) and three tilt values (55%, 75%, and 95%) were tested randomly. The energy and leading edge voltage at 50% defibrillation success (E50 and V50) were used to evaluate defibrillation efficacy. E50 and V50 were determined by the Bayesian technique. The lowest stored E50 for the 30μF, 60 μF, and 120 μF waveforms were 90 ± 12 J (95% tilt), 106 ± 45 J (55% tilt), and 107 ± 52 J (75% tilt), respectively. The lowest V50 for the 30 μF, 60 μF, and 120 μF waveforms were 2,439 ± 166 V (95% tilt), 1,849 ± 375 V (55% tilt), and 1,301 ± 322 V (75% tilt), respectively. The average current at external defibrillation threshold demonstrated a strength versus pulse duration relationship similar to that seen with pacing. Reducing capacitance has the same effect as truncating the waveform. The E50 is more sensitive to tilt values changes in larger capacitance waveforms. This study suggests that the optimal combination between capacitance and tilt may be 120 μF and 55%–75% for external defibrillation. (PACE 2003; 26:2213–2218)
Clinical Experience with an Automatic Threshold Tracking Algorithm Study
Authors: KENNERGREN CHARLES , LARSSON BERIT , UHRENIUS ÅSA , GADLER FREDRIK ,   on Behalf of the Study Group
Published: December 2003

The automatic threshold tracking pacing system algorithm developed by St. Jude Medical, verifies ventricular capture beat by beat by recognizing the evoked response (ER) following each pacemaker stimulus. The present automatic threshold tracking function requires a bipolar ventricular lead with low polarization. The aim of this study was to evaluate a new algorithm developed to use with unipolar leads with different levels of polarization. An external pacemaker with the ability to sense intrinsic R waves and measure ER signals, as well as deliver stimulus, was used. An algorithm for detecting the true ER in a unipolar sensing configuration (tip‐case) was developed. Based on the assumption that the true evoked R wave amplitude is independent of the stimulation amplitude, the algorithm calculates and subtracts the polarization present at any pacing stimulus from the measured ER. The resulting signal is analyzed to verify capture. This study comprises 35 patients of which 26 were new implants and 9 had chronic leads. The automatic threshold‐tracking algorithm was calibrated for each patient and pacing was performed at different pulse amplitudes and pulse duration. Capture was verified for each paced beat. The recordings were stored for later comparison with the tape‐recorded intracardiac heart signals. The new algorithm correctly verified capture or loss of capture for every single analyzed beat at the different pacing outputs in every individual patient. The results from this initial study suggests that the new ER detection principle will allow automatic threshold tracking to be used not only with low polarization bipolar leads but with most leads. (PACE 2003; 26:2219–2224)
Durability of Repaired Sensing Leads Equivalent to that of New Leads in Implantable Cardioverter Defibrillator Patients with Sensing Abnormalities
Authors: MAHAPATRA SRIJOY , HOMOUD MUNTHUR K. , WANG PAUL J. , MARK ESTES N.A. , LINK MARK S.
Published: December 2003

Breaks in the insulation portions of implantable cardioverter defibrillator (ICD) leads may cause nonphysiological sensing and subsequent inappropriate ICD therapy, and may also interfere with the sensing and pacing functions of the ICD. Previously, leads with insulation breaks have been replaced with new sensing leads. However, repair of leads, utilizing a commercially available patch kit may reduce the morbidity, hospital stay, and cost of lead replacement. The long‐term durability of these repairs has not previously been reported and is the subject of this study. Patients undergoing ICD sensing lead repair or replacement constituted the study population. Patients were followed at 3 month intervals with an endpoint of new lead abnormalities necessitating repeat lead repair or replacement. Twenty‐five patients underwent lead repair and 27 individuals underwent lead replacement for either preoperative nonphysiological sensing (n = 25) or intraoperative evidence of insulation break (n = 27). There was no significant difference between the individuals undergoing lead repair or replacement in age (59 ± 9 vs 60 ± 12 years), mean left ventricular ejection fraction (40%± 18% vs 33%± 17%) or age of the lead being repaired or replaced (4.5 ± 2.0 years vs 5.0 ± 2.0 years). During follow‐up of 44 ± 23 months, 4 of the repaired leads and 4 of the replaced leads developed new insulation breaks requiring surgical intervention (P = 0.43). In conclusion, in nearly 4 years of follow‐up of patients with sensing lead insulation breaks, there was no difference is subsequent lead survival in those with lead repair compared to those with new sensing leads inserted. The strategy of lead repair, when technically feasible, should thus be considered in all patients with sensing abnormalities secondary to insulation breaks. (PACE 2003; 26:2225–2229)
Optimal Pacing for Symptomatic AV Block:
Authors: HUANG MAX , KRAHN ANDREW D. , YEE RAYMOND , KLEIN GEORGE J. , SKANES ALLAN C.
Published: December 2003

VDD pacing provides the physiological benefits of atrioventricular synchronous pacing with the convenience of a single lead system, but is hampered by uncertainty regarding long‐term atrial sensing and potential development of sinus node disease. To examine the long‐term reliability and complication rates of VDD pacing, we compared the outcome of 112 consecutive patients (age 70 ± 13 years, 59% male) with symptomatic AV block who received a single pass bipolar VDD system to 80 patients (age 63 ± 16 years, 70% male) who received DDD pacing for the same indication. All patients were judged to have intact sinus node function based on submitted ECGs and monitoring results at the time of implant. Implant time was reduced in VDD patients compared to DDD patients (63 ± 20 vs 97 ± 36 minutes, P < 0.0001). Implant complications occurred in 5 (6%) DDD patients compared to 3 (3%) VDD patients (P = 0.15). The implant P wave was lower with VDD pacing compared to DDD patients (2.91 ± 1.48 vs 4.0 ± 1.7 mV, P < 0.0001), but remained stable during long‐term follow‐up in both groups. During 17.7 ± 10.0 months of follow‐up in the VDD group, only 2 VDD patients were reprogrammed to VVIR mode, compared to 3 DDD patients. Physiological atrioventricular activation was maintained in 94%–99% of beats throughout the follow‐up period in the VDD group. VDD pacing is an excellent strategy for treatment of patients with symptomatic AV block. The lower cost, high reliability, and abbreviated implantation time suggest that VDD pacing is a viable alternative to DDD pacing in patients with high‐degree AV block and normal sinus node function. (PACE 2003; 26:2230–2234)
Factors Determining ICD Implantation in Drug Therapy Patients After Termination of Antiarrythmics Versus Implantable Defibrillators Trial
Authors: KLEIN RICHARD C. , SCHRON ELEANOR B. , GRAHAM RENFROE ELLEN , HALLSTROM AL , KRON JACK , OCAMPO CELESTE , LEONEN ANNA , TULLO NICHOLAS ,   THE AVID INVESTIGATORS
Published: December 2003

Because of a significant survival benefit in the defibrillator arm of the Antiarrhythmics versus Implantable Defibrillator (AVID) Trial, patients in the antiarrhythmic drug (AAD) arm were advised to undergo ICD implantation. Despite this recommendation, ICD implantation in AAD patients was variable, with a large number of patients not undergoing ICD implantation. Patients were grouped by those who had been on AAD < 1 year (n = 111) and those on AAD > 1 year (n = 223). Multiple clinical and socioeconomic factors were evaluated to identify those who might be associated with a decision to implant an ICD. The primary reason for patients not undergoing ICD implantation was collected, as well as reasons for a delayed implantation, occurring later than 3 months from study termination. Of 111 patients on AAD for less than 1 year, 53 received an ICD within 3 months compared to 40/223 patients on AAD for more than 1 year (P < 0.001). Patient refusal was the most common reason to not implant an ICD in patients on drug < 1 year; physician recommendation against implantation was the most common in patients on drug > 1 year. Multivariate analysis showed ICD recipients on AAD < 1 year were more likely to be working and have a history of myocardial infarction (MI), while those on AAD > 1 year were more likely to be working, have a history of MI and ventricular fibrillation, and less likely to have experienced syncope, as compared to those who did not get an ICD. Having private insurance may have played a role in younger patients receiving an ICD. (PACE 2003; 26:2235–2240)
Conduction Properties of the Crista Terminalis in Patients with Atrial Flutter Due to Amiodarone Therapy for Atrial Fibrillation
Authors: TAI CHING‐TAI , LIN YUNG‐KUO , LAN FEI‐CHIUN , CHEN HUNG‐YI , DING YU‐AN , CHANG MAU‐SONG , CHEN SHIH‐ANN
Published: December 2003

Some patients with atrial fibrillation (AF) treated by antiarrhythmic drugs (AAD) can develop typical atrial flutter, but the mechanism is not clear. This study included 21 patients with AF. Group I (n = 7) had typical atrial flutter due to amiodarone therapy. Group II (n = 7) did not develop atrial flutter after amiodarone treatment. Group III (n = 7) did not receive AAD treatment. A 7 Fr, 20‐pole electrode catheter was placed along the CT identified by fluoroscopy and intracardiac echocardiography. After restoration of the sinus rhythm, decremental pacing near the CT was performed until 2 to 1 atrial capture. Complete transverse conduction block was defined as the appearance of double potentials with opposite activation sequence along the CT. Focal transverse conduction delay was defined as the appearance of double potentials at ≥ 2 recording sites. Focal transverse conduction delay was observed during pacing at the cycle length of 693 ± 110 ms in group I, 360 ± 97 ms in group II and 343 ± 109 ms in group III (P = 0.001). Complete transverse conduction block was observed during pacing at the cycle length of 391 ± 118 ms in group I and 231 ± 23 ms in group II (P = 0.001), but not in group III. In conclusion, focal transverse conduction delay in the CT was common in patients with AF. A predisposition to the line of the conduction block in the CT might contribute to the conversion of AF to typical atrial flutter due to amiodarone therapy. (PACE 2003; 26:2241–2246)
Induction of Atrial Fibrillation and Nerve Sprouting by Prolonged Left Atrial Pacing in Dogs
Authors: AKIRA HAMABE , CHANG CHE‐MING , ZHOU SHENGMEI , CHOU CHUNG‐CHUAN , YI JOHNNY , MIYAUCHI YASUSHI , OKUYAMA YUJI , FISHBEIN MICHAEL C. , KARAGUEUZIAN HRAYR S. , CHEN PHD; LAN S. , CHEN PENG‐SHENG
Published: December 2003

The authors hypothesized that rapid electrical stimulation can induce nerve sprouting in canine atria, and that LA pacing is more effective than RA pacing in inducing sustained AF. Chronic rapid (20 Hz) LA epicardial pacing was performed in six dogs. Sustained AF (>48 hours) was induced within 23 ± 8 days, which was much faster than that with RA endocardial pacing using the same protocol (139 ± 84 days, P < 0.05). Nerves were identified by immunocytochemical techniques. In all dogs, growth‐associated protein 43‐positive (sprouting) nerve density was highest near the pacing site, and the rapid LA pacing resulted in differential nerve sprouting among the LA, left superior pulmonary vein (LSPV), interatrial septum (IAS), and RA (5521 ± 1496, 3154 ± 2355, 3953 ± 1164, 1559 ± 1077 μm2/mm2, respectively, P = 0.0032). Tyrosine hydroxylase‐positive (sympathetic) nerve density were not significantly different among groups (2726 ± 1165, 1586 ± 558, 2156 ± 1741, 1509 ± 1242 μm2/mm2, respectively). The nerves were inhomogeneously distributed. LA epicardial pacing induced sustained AF much faster than RA endocardial pacing and rapid electrical stimulation can induce inhomogeneous nerve sprouting near the pacing site. (PACE 2003; 26:2247–2252)
Noncontact Mapping of Ventricular Tachycardia in a Closed‐Chest Animal Model of Chronic Myocardial Infarction
Authors: REEK SVEN , GELLER J. CHRISTOPH , MITTAG ANTJE , GROTHUES FRANK , HESS ANDREAS , KAULISCH THOMAS , KLEIN HELMUT U.
Published: December 2003

Treatment of ventricular tachyarrhythmias in the setting of chronic myocardial infarction requires accurate characterization of the arrhythmia substrate. New mapping technologies have been developed that facilitate identification and ablation of critical areas even in rapid, hemodynamically unstable ventricular tachycardia.

A noncontact mapping system was used to analyze induced ventricular tachycardia in a closed‐chest sheep model of chronic myocardial infarction. Twelve sheep were studied 96 ± 10 days after experimental myocardial infarction. During programmed stimulation, 15 different ventricular tachycardias were induced in nine animals. Induced ventricular tachycardia had a mean cycle length of 190 ± 30 ms. In 12 ventricular tachycardias, earliest endocardial activity was recorded from virtual electrodes, preceding the surface QRS onset by 30 ± 7 ms. Noncontact mapping identified diastolic activity in ten ventricular tachycardias. Diastolic potentials were recorded over a variable zone, spanning more than 30 mm. Timing of diastolic potentials varied from early to late diastole and could be traced back to the endocardial exit site. Entrainment with overdrive pacing was attempted in nine ventricular tachycardias, with concealed entrainment observed in seven. Abnormal endocardium in the area of chronic myocardial infarction identified by unipolar peak voltage mapping was confirmed by magnetic resonance imaging.

These data suggest that induced ventricular tachycardia in the late phase of myocardial infarction in the sheep model is due to macroreentry involving the infarct borderzone. The combination of this animal model with noncontact mapping technology will allow testing of new strategies to cure and prevent ventricular tachycardia in the setting of chronic myocardial infarction. (PACE 2003; 26:2253–2263)
Electrical Characteristics of a Split Cathodal Pacing Configuration
Authors: MAYHEW MARC W. , JOHNSON PHILIP L. , SLABAUGH JANE E. , BUBIEN ROSEMARY S. , KAY G. NEAL
Published: December 2003

Several electrical configurations can be used for biventricular pacing to achieve cardiac resynchronization. Commercially approved biventricular pacing systems stimulate the RV with an endocardial lead and the LV with a unipolar lead positioned in the cardiac venous circulation using the tip electrodes of both leads linked as a common cathode. The distribution of current with this parallel circuit, split cathodal configuration is dependent on the separate impedances of the two leads. A total of 19 patients with left bundle branch block and congestive heart failure underwent implantation of a cardiac venous lead and standard bipolar right atrial and RV pacing leads. Stimulation thresholds and impedances were measured for the RV and LV in five electrical configurations: (1) unipolar LV from the cardiac venous lead; (2) bipolar LV using the tip electrode in the cardiac vein as the cathode and the ring electrode of the RV lead as the anode; (3) bipolar RV from the RV lead; (4) unipolar split cathodal stimulation of the cardiac venous and RV leads; and (5) bipolar split cathodal stimulation of the cardiac venous and RV leads. Repeat measurements of RV and LV thresholds were made from the pulse generator at 1‐year follow‐up. The LV stimulation threshold increased from 0.7 ± 0.5 V in the unipolar configuration to 1.0 ± 0.8 V in the unipolar split cathodal configuration (P = 0.01) and from 1.0 ± 0.7 V in the bipolar configuration to 1.3 ± 0.9 V in the bipolar split cathodal configuration (P < 0.001). The RV stimulation threshold increased from 0.3 ± 0.2 V in the bipolar configuration to 0.5 ± 0.2 V in the bipolar split cathodal configuration (P = 0.005). The bipolar impedance measured 874 ± 299 Ω for the coronary venous lead, 705 ± 152 for the RV lead, 442 ± 87 in the split unipolar cathodal configuration, and 516 ± 64 in the bipolar split cathodal configuration. At 1‐year follow‐up, the LV stimulation threshold was 1.8 ± 1.6 in the unipolar split cathodal configuration and 2.4 ± 1.6 in the bipolar split cathodal configuration (P = 0.003). The RV stimulation threshold at 1 year was 0.7 ± 0.3 in the unipolar split cathodal configuration and 0.8 ± 0.3 in the bipolar split cathodal configuration (P = 0.02). The split cathodal configuration significantly increases the apparent stimulation threshold for both the LV and the RV as compared with individual stimulation of either chamber alone. Programming to the bipolar split cathodal configuration further increases the apparent stimulation threshold. These observations support the development of pacing systems with separate LV and RV output circuits for resynchronization therapy. (PACE 2003; 26:2264–2271)
An Approach to Measure Atrial and Ventricular Heart Rate Variability Using Pacemaker‐Mediated Intracardiac Electrograms
Authors: SCHUCHERT ANDREAS , WAGNER STEFAN M. , MEINERTZ THOMAS
Published: December 2003

Heart rate variability (HRV) measurements are usually performed from ventricular beat‐to‐beat intervals because of the difficulty to precisely locate the P wave fiducial point in surface ECG recordings. The aim of the study was to describe an approach to determine the atrial and ventricular HRV using pacemaker‐mediated intracardiac electrograms. Twelve patients with the dual chamber pacemaker Logos were included. The atrial and ventricular intracardiac electrograms were transmitted with the high resolution telemetry channel of the pacemaker to an external recorder for 20 minutes while the patients were supine. During the measurements the patients were in sinus rhythm with intrinsic AV conduction. After computer assisted triggering of the atrial and ventricular events, the resultant intervals were used to calculate the standard deviation of all NN intervals (SDNN), the square root of the mean squared differences of successive NN intervals (RMSSD), and the percentage of successive interval differences >50 ms (pNN50). The differences between atrial and ventricular HRV‐Indexes were assessed for each patient with a cut‐off point of 1%. Differences >1% were analyzed in detail. A total of 15,504 heart cycles were analyzed. A manual correction due to false or not triggered atrial or ventricular events was necessary in 0.9%. The overall difference between atrial and ventricular pNN50 was

−0.5%±2.1%

and differences >1% were observed in 4 patients. The NN50 events occurred in the atrial as well as in the related ventricular interval in 84%. NN50 events occurred only in the atrium in 6% and only in the ventricle in 10%. The mean differences between atrial and ventricular SDNN and RMSSD were

0.4±2.1

ms and

−0.1±3.5  ms

with intra‐individual differences <1%. The present study described a new method and demonstrated its feasibility to determine atrial as well as ventricular HRV from pacemakermediated intracardiac electrograms. The differences for pNN50 indicate that ventricular HRV did not reflect the changes of sinus node activity in all patients. (PACE 2003; 26:2272–2274)
Safety and Efficacy of a Dual Chamber Implantable Cardioverter Defibrillator Capable of Slow Ventricular Tachycardia Discrimination:
Authors: MLETZKO RALPH , ALIOT ETIENNE , SEIDL KARLHEINZ , LAVERGNE THOMAS , MABO PHILIPPE , HOHNLOSER STEFAN , BÖCKER DIRK , SCHOELS WOLFGANG , SADOUL NICOLAS
Published: December 2003

New developments in dual chamber implantable cardioverter defibrillators (ICD) have increased the specificity of therapy delivery. This study was performed to examine the performance of an algorithm, focusing on its ability to distinguish slow ventricular tachycardia (VT) from sinus rhythm or supraventricular tachyarrhythmias. The patient population included 77 men and 13 women, 63 ± 11 years old, treated with ICDs after episodes of spontaneous or inducible ventricular tachyarrhythmias. They were randomized to programming of the ICD to a lower limit of VT detection at 128 beats/min (group I, n = 44), versus 153 beats/min II (group II, n = 46). The primary endpoint of the study consisted of comparing the specificity and sensitivity of the algorithm between the two groups of patients. Over a 10.1 ± 3.5 months follow‐up, 325 episodes were detected in the Tachy zone in group I, versus 106 in group II. The sensitivity and specificity of the algorithm in group I were 98.8% and 94.4%, respectively, versus 100% and 89% in group II (NS). A single episode of VT at a rate of 132 beats/min was diagnosed as SVT in group I. The sensitivity and specificity of the algorithm for tachycardias <153 beats/min were 97.4% and 94.5%, respectively. Overall VT therapy efficacy was 100% in both groups. The performance of this algorithm in the slow VT zone supports the programming of a long Tachy detection interval to document slow events, and allows to treat slow VT, if necessary, without significant risk of inappropriate interventions for sinus tachycardia. (PACE 2003; 26:2275–2282)
Managing Pacemaker Safety Alerts:
Authors: GUREVITZ OSNAT , GRANIT CHAVA , BAR‐LEV DAVID , LURIA DAVID , LIPCHENCA IGOR , ROTSTEIN ZEEV , ELDAR MICHAEL , GLIKSON MICHAEL
Published: December 2003

This report describes the experience of a large pacemaker center during three successive replacement operations due to safety alerts involving three models from the same manufacturer. Between March 1993 and May 1999, 210 patients were implanted with three DDD pacemaker models (Sorin Biomedica, Saluggia, Italy) that were subsequently subject to safety alerts. Pacemaker records were reviewed for complications related to device malfunction, and those secondary to the replacement procedure. Pacemaker malfunction was observed in 16.4% of units despite much lower estimates from the company (range 1–4%). With the exception of one, all units were replaced. Malfunctions were discovered in 7 of 20 pacemakers following an urgent call for follow‐up issued as a result of the alert. Twenty units implanted as substitutes for those replaced following the first alert turned out to be subject to the third alert. Significant clinical consequences of malfunction occurred in 5.3% of patients including a near fatal event in one case, while complications related to the replacement procedure occurred in 8.3% of patients, including one fatality. On the issuance of a safety alert, failure rates in a particular center may be higher than published by the manufacturer, and should prompt action by the center to weigh local incidence of device failure against complications of replacement procedures. When device failure mechanism is not entirely clear, particularly in cases of successive model failures, replacement devices from a different manufacturer should be considered. (PACE 2003; 26:2283–2288)
Implantable Cardioverter Defibrillator Events in Patients with Asymptomatic Nonsustained Ventricular Tachycardia:
Authors: RUSSO ANDREA M. , NAYAK HEMAL , VERDINO RALPH , SPRINGMAN JAMIE , GERSTENFELD EDWARD , HSIA HENRY , MARCHLINSKI FRANCIS E.
Published: December 2003

Primary prevention trials have demonstrated that patients with coronary disease, reduced left ventricular function, and nonsustained ventricular tachycardia (NSVT) have improved survival with implantable cardioverter defibrillator (ICD) therapy, presumably secondary to effective termination of life‐threatening arrhythmias. However, stored intracardiac electrograms were not always available and specific arrhythmias leading to ICD therapy were not always known. We examined the occurrence of ICD events in 51 consecutive patients who match the described patient profile to determine the frequency of appropriate and inappropriate ICD therapy. ICD detections were noted in 18 (35%) patients during a median follow‐up period of 13.1 months. Appropriate therapy for sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) occurred in 11 (22%) patients, with appropriate shocks in 8 (16%) patients and appropriate antitachycardia pacing (ATP) in 4 (8%) patients. The time to first appropriate therapy occurred at a mean of 17 ± 12 months (median 18 months, range 3–36 months). Inappropriate therapy occurred in 5 (10%) patients with inappropriate shocks in 4 patients and inappropriate ATP in 2 patients. Inappropriate therapy was delivered for supraventricular arrhythmias (SVAs) in 4 patients and for T wave oversensing in 1 patient. The reason for shock therapy was unknown in 1 patient (2%) due to ICD malfunction. The mean arrhythmia rate leading to appropriate therapy for VT/VF was 232 ± 72 beats/min (range 181‐400 beats/min), and the mean rate leading to inappropriate therapy for SVT was 168 ± 10 beats/min (range 160‐180 beats/min).

Patients with coronary disease and asymptomatic NSVT commonly receive appropriate defibrillator therapy. These results support the need for ICD implantation for primary prevention, with attention to careful programming of the detection rate to prevent inappropriate therapy. (PACE 2003; 26:2289–2295)
Differential Diagnosis of Slow/Slow Atrioventricular Nodal Reentrant Tachycardia from Atrioventricular Reentrant Tachycardia Using Concealed Posteroseptal Accessory Pathway by 12‐Lead Electrocardiography
Authors: OH SEIL , CHOI YUN‐SHIK , SOHN DAE‐WON , OH BYUNG‐HEE , LEE MYOUNG‐MOOK , PARK YOUNG‐BAE
Published: December 2003

Slow pathways are used as both antegrade and retrograde conduction pathway in slow/slow atrioventricular nodal reentrant tachycardia (SS‐AVNRT), and patients with SS‐AVNRT have tachycardia ECGs mimicking atrioventricular reentrant tachycardia using concealed posteroseptal accessory pathway (PS‐AVRT). Therefore, SS‐AVNRT can be misdiagnosed as PS‐AVRT, and the differential diagnosis is clinically important. Standard 12‐lead ECGs during tachycardia were analyzed in patients with SS‐AVNRT (n = 10) and PS‐AVRT (n = 10). All these patients were diagnosed by electrophysiological study and underwent successful catheter ablation. Differences of the RP' intervals (dRP') between V1 and the inferior leads were evaluated. SS‐AVNRT had significantly longer RP' intervals measured in V1 (167 ± 25.2 vs 137 ± 26.8 ms, SS‐AVNRT vs PS‐AVRT, respectively, P = 0.02), longer dRP' between V1 and II (dRP'[V1‐II], 37 ± 14 vs 17 ± 6.7 ms, P = 0.0007), longer dRP'[V1‐III] (39 ± 14 vs 17 ± 9.9 ms, P = 0.0011), and longer dRP'[V1‐aVF] (39 ± 13 vs 20 ± 9.5 ms, P = 0.0008). The following criteria were suggested for differential diagnosis of SS‐AVNRT from PS‐AVRT: dRP'[V1‐II] >25 ms (sensitivity and specificity: 80% and 100%, respectively), dRP'[V1‐III] >23 ms (90% and 90%), dRP'[V1‐aVF] >30 ms (90% and 90%). Differences of the RP' intervals between V1 and the inferior leads in the tachycardia ECGs were useful for differential diagnosis of SS‐AVNRT from PS‐AVRT. (PACE 2003; 26:2296–2300)