bluuebunny/crossref_metadata_2025 huggingface dataset:
Is pre‐eclampsia more than one disease?
Authors: Vatten Lars J. , Skjærven Rolv
Published: March 2004

Objectives The clinical characteristics of pre‐eclampsia (gestational hypertension and proteinuria) may represent separate pathogenetic conditions. Pre‐eclampsia accompanied by restricted fetal growth may originate from abnormal implantation, and appropriate or high birthweights may indicate a mixture of conditions, ranging from mild pre‐eclampsia with modest placental involvement to hypertensive conditions without placental disease.

Design Prospective, observational study.

Setting General population.

Population We used data from the Medical Birth Registry of Norway, a population‐based registry that has recorded births since 1967. For this study, we used information on length of gestation and presence of pre‐eclampsia among 1,679,205 singletons born between 1967 and 1998. Pre‐eclampsia was diagnosed in 44,220 (2.6%) pregnancies.

Methods We studied the risk of pre‐eclampsia in relation to standardised measures (zscores) of birthweight, adjusted for length of gestation, and stratified by term and preterm delivery. We also explored whether gestational diabetes was more prevalent in conjunction with preterm than term pre‐eclampsia.

Main outcome measures Pre‐eclampsia diagnosed at term or preterm.

Results For pre‐eclampsia diagnosed around term, there was a U‐shaped association with birthweight. Compared with appropriate birthweights for gestation, the risk of term pre‐eclampsia was more than fourfold higher (relative risk [RR] 4.5, 95% confidence interval [CI], 4.3 to 4.7) if the baby's birthweight was lower than two standard deviations under the mean. For birthweights three standard deviations or higher than the mean, pre‐eclampsia was more than twice as likely (RR 2.6, 95% CI 2.2–2.9). In contrast, the risk of preterm pre‐eclampsia displayed an L‐shaped association with birthweight. Low birthweight (less than −2 standard deviations) was associated with greatly increased risk (RR 9.9, 95% CI 9.1–10.9), but for high birthweights (≥3 standard deviations), there was no association with the risk of preterm pre‐eclampsia (RR 1.2, 95% CI 0.7–2.1). The prevalence of gestational diabetes was three times (prevalence ratio 3.3, 95% CI 2.6–3.6) higher in preterm than term pre‐eclampsia.

Conclusion Whereas pre‐eclampsia with preterm delivery associated with low birthweight may be caused by underlying placental abnormality, pre‐eclampsia delivered at term may represent a mixture of conditions, ranging from mild pre‐eclampsia with moderate placental affection to hypertensive conditions in pregnancy without placental dysfunction.
Non‐protein‐bound iron and free radical damage in fetuses with rhesus haemolytic disease: influence of intrauterine transfusions
Authors: Luykx L.M. , Berger H.M. , Geerdink J. , Kanhai H.H.H. , Egberts J.
Published: March 2004

Objective  To determine iron‐induced free radical damage in fetal rhesus haemolytic disease (RHD) before and after repeated intrauterine red blood cell transfusions and its relation to hydrops fetalis.

Design  Prospective, observational study.

Setting  Department of Obstetrics, Leiden University Medical Centre, the Netherlands.

Population  Fifty anaemic fetuses, including 13 hydropic ones, 9 preterm and 12 term neonates and 8 female non‐pregnant adults.

Methods  Venous blood plasma samples were collected from 50 fetuses suffering from RHD preliminary to the first, and if appropriate, subsequent intrauterine red blood cell transfusions for determination of iron status including non‐protein‐bound iron (NPBI) and iron‐binding primary antioxidant proteins, total plasma anti‐oxidant capacity and its contributing secondary antioxidants (e.g. vitamin C, uric acid, sulphydryl groups and peroxidation products). Results were compared with values of healthy preterm and term neonates directly at birth and adult controls. Within the fetal haemolytic group, 13 hydropic fetuses were analysed as a separate group.

Main outcome measures  Non‐protein‐bound iron, antioxidants, total antioxidant capacity and peroxidation products. Sub analysis of the outcome measures of the hydropic fetuses.

Results  RHD fetuses had at initial cordocentesis a significantly higher NPBI level and a significantly lower total plasma antioxidant capacity than control babies and adults. Their vitamin C tended to be more oxidised but lipid peroxidation had not increased, when compared with preterm babies. The repeated intrauterine red blood cell transfusions had a positive effect on the total antioxidant capacity of plasma and did not increase the concentration of NPBI. The hydropic fetuses, who had higher NPBI concentrations and lower plasma protein concentrations and total antioxidant capacity, did not show more peroxidation products in plasma than the non‐hydropic fetuses. Fetuses without reversal of hydrops despite intrauterine transfusions showed decreasing levels of proteins with subsequent transfusions but peroxidation products remained constant.

Conclusion  Repeated intrauterine red blood cell transfusions do not lead to free radical damage in the fetus in utero. Iron‐induced free radical activity does not appear to play a causative role in the proceeding of hydrops fetalis in RHD.
Prevention of residual urinary incontinence following successful repair of obstetric vesico‐vaginal fistula using a fibro‐muscular sling
Authors: Browning Andrew
Published: March 2004

Obstetric vesico‐vaginal fistula remains a significant cause of female urinary incontinence worldwide. Approximately 2 million women suffer from this condition, perhaps many more, most of whom are in Africa. Very few centres are treating these patients, and although success rate in the closure of the fistula is high, up to 92%, this does not necessarily equate to a cure. A significant proportion of women remains with urinary incontinence. Little is known about the nature of this incontinence, and even less is known about how to manage it. This article describes a new and simple surgical procedure, which, when employed at the time of fistula closure, seems to reduce the incidence of residual incontinence in those women at a higher risk of developing it.
Utilisation of hormone replacement therapy in the United Kingdom
Authors: Bromley S.E. , de Vries C.S. , Farmer R.D.T.
Published: March 2004

Objective  To determine prevalence and patterns of hormone replacement therapy (HRT) utilisation in women in the UK.

Design  Prospective observational study.

Setting  UK general practice.

Population  Women from general practices throughout the UK.

Methods  The study period was 1 January 1992 to 31 December 1998. Age‐specific prevalence was calculated for each year. Trends in prescribing patterns were described over time. A sub‐cohort of ‘new starters’ on HRT was identified to establish patterns of use, including duration of use and switching of preparations. Characteristics of the sub‐cohort were compared with a reference group of non‐HRT users.

Main outcome measures  Prevalence, prescribing patterns and differences in characteristics between HRT users and non‐HRT users.

Results  Among women aged 45–64, prevalence of HRT use increased from 18.6% in 1992 to 27.7% in 1998. Secular trends were observed away from prescribing combined‐sequential preparations and towards use of combined‐continuous preparations. Among the prescriptions for combined HRT products, only 4.3% contained medroxyprogesterone acetate (MPA). A total of 45.7% of women without a record of a hysterectomy and 53.8% of women with a record of a hysterectomy used HRT for at least three years. When women were partitioned by year of starting HRT, there was a trend of increasing duration of use across the seven years. Some women without a record of a hysterectomy were receiving unopposed oestrogen without progestogen supplementation.

Conclusions  Within the past decade, use of HRT has increased among women in the UK with large numbers of women using HRT for long periods and treatment often tailored to the individual.
Efficacy of preemptive analgesia for wound pain after laparoscopic operations in infertile women: a randomised, double‐blind and placebo control study
Authors: Lam K.W. , Pun T.C. , Ng E.H.Y. , Wong K.S.
Published: March 2004

Objective  To compare preemptive analgesia and preclosure analgesia in reducing wound pain after laparoscopic operation.

Design  Randomised, double‐blind and placebo control.

Setting  University referral centre.

Population  Infertile women undergoing diagnostic laparoscopy with or without additional procedures.

Methods  One hundred and forty‐four women were randomised to receive 10 mL of 1% lignocaine at the surgical sites before incision and 10 mL of normal saline before closure of incision (the preemptive group), saline before incision and lignocaine before closure of incision (the preclosure group) and saline at the surgical sites both before incision and closure of incision (the placebo group).

Main outcome measures  Post‐operative wound pain measured by linear visual analogue scale and amount of analgesic use.

Results  The women in the preclosure group had significantly lower pain scores at 2, 4 and 24 hours than those in the placebo group, whereas the women in the preemptive group only showed significantly lower pain scores at 2 hours than the placebo group. The pain score at 24 hours in the preclosure group was significantly lower than that in the preemptive group. There was no significant difference in the post‐operative analgesic requirement among the three groups.

Conclusion  The preclosure analgesia is better than preemptive analgesia and no analgesia in reducing post‐operative wound pain.
Cervical screening in women over the age of 50: results of a population‐based multicentre study
Authors: Flannelly Grainne , Monaghan John , Cruickshank Maggie , Duncan Ian , Johnson Jane , Jordan Joe , Campbell Marion , Patnick Julietta
Published: March 2004

Objective  It has been suggested that women over 50 with a satisfactory negative smear history are at low risk for dyskaryosis and might be suitable for withdrawal from the cervical screening programme. The objectives of this study are to document the pattern of dyskaryosis in the cervical smears of women over 50 and to relate the risk of dyskaryosis in these women to the prior smear history.

Design  Available computerised smear data were analysed.

Setting  Five regions in England and Scotland; Aberdeen, Dundee, Birmingham, Gateshead and Nottingham.

Population All women aged 50 or over who had a satisfactory smear between 1988 and 1996.

Methods  Smear results were sorted into individual smear records. The first smear after the age of 50 was identified as well as all smears before and after the age of 50.

Main outcome measurements  The smear history before and after the age of 50 was determined for all women. The relative risk of dyskaryosis as well as the time to dyskaryosis was calculated for women whose raw data were available.

Results  The study included 170,436 women with at least one satisfactory smear after 50. No results of previous smears were available in 90,546 (54%) of women but 36,512 (21%) of women had a satisfactory negative smear history. Women with prior dyskaryosis or borderline nuclear abnormalities (BNA) had an increased risk of dyskaryosis after the age of 50 compared with women with a negative history (RR 4.39 and 3.08 respectively). It was notable that 1.8% of women with a negative history still demonstrated subsequent dyskaryosis.

Conclusions  Women with either dyskaryosis or BNA before 50 are not suitable for withdrawal from cervical screening. Well‐screened women with a negative smear history at the age 50 still have a residual risk of subsequently developing a new abnormality.
An intergenerational study of birthweight: investigating the birth order effect
Authors: Hyppönen Elina , Power Chris
Published: March 2004

In a two‐generation study of the nationwide 1958 British cohort and their offspring, we investigated the intergenerational influence of birth order on birthweight. Despite increases in own birthweight by birth order and a positive parent–offspring correlation in birthweights, there was a suggestion that parental birth order was inversely associated with offspring birthweight. This paradoxical finding was due to differential intergenerational birthweight associations, with a weaker association in later‐born compared with first‐born parents. Our findings suggest that underlying causes of a given birthweight should be taken into account in studies that investigate long term health outcomes.
The natural history of primary dysmenorrhoea: a longitudinal study
Authors: Weissman Alicia M. , Hartz Arthur J. , Hansen Michael D. , Johnson Susan R.
Published: March 2004

Objective  To describe the prevalence, severity, course and predictive factors of primary dysmenorrhoea in women of all reproductive ages.

Design  Prospective mailed surveys in 1985 and 1991.

Setting  University of Iowa, College of Nursing.

Population  We began with a stratified sample of 996 nurses who graduated between 1963 and 1984. We analysed data from 404 women who responded to both surveys, but denied endometriosis, pelvic inflammatory disease or uterine fibroids.

Methods  Participants were surveyed twice at an interval of six years (response rates 73% and 78%) regarding menstrual cycle characteristics. For analysis, dysmenorrhoea was dichotomised as none/mild or moderate/severe. We analysed predictive factors using χ2 tests and stepwise logistic regression.

Main outcome measure  Severity of dysmenorrhoea. Menstrual cramps as experienced when not taking medication to prevent discomfort were rated on a four‐point scale: 0 = no dysmenorrhoea, 1 = minimal (can work, somewhat uncomfortable), 2 = moderate (can work, but quite uncomfortable) or 3 = severe dysmenorrhoea (miss work, have to be in bed).

Results  In 1985, 80% of respondents were >25 years old and 60% were parous. There were few changes over six years in the prevalence of mild (51% to 53%), moderate (22% to 20%) or severe dysmenorrhoea (4% to 2%). After adjusting for dysmenorrhoea in 1985, each live birth during follow up (OR = 0.20, 95% CI = 0.08 to 0.53) and older age (OR = 0.92, 95% CI = 0.86 to 0.98) were associated with less dysmenorrhoea in 1991.

Conclusions  Primary dysmenorrhoea affects most women throughout the menstrual years. Dysmenorrhoea severe enough to cause absence from work occurs in less than 5% of women. Although improvement and worsening are equally likely for all women, improvement is more likely in women who bear children.
A prospective randomised trial of atosiban versus hexoprenaline for acute tocolysis and intrauterine resuscitation
Authors: Afschar Pedram , Schöll Wolfgang , Bader Arnim , Bauer Margit , Winter Raimund
Published: March 2004

Objective  The aim of this study was to compare the efficacy and side effect profile of atosiban with hexoprenaline when used for intrauterine resuscitation of intrapartum fetal distress.

Study design  Women in labour with acute intrapartum fetal distress detected by cardiotocography were randomly assigned to receive intravenous atosiban or hexoprenaline.

Setting  Department of Obstetrics and Gynecology, Karl Franzens University of Graz and General Hospital Graz, Austria.

Population or sample  One thousand and four hundred and thirty‐one women with singleton pregnancy at term and cephalic presentation were enrolled in the study during October 2000 and May 2001.

Methods  A prospective, randomised, pilot study with no a priori sample size calculation.

Main outcome measure  Efficacy of treatment for stopping uterine contractions and the resumption of contractions determined by fetal heart rate monitoring.

Results  Tocolysis was achieved in 92% (12/13) of the women receiving atosiban and 100% (13/13) of those receiving hexoprenaline. Maternal tachycardia developed in 1/13 women, receiving atosiban and 10/13 women hexoprenaline. Hypertension occurred in 1/13 on atosiban and 3/13 women on hexoprenaline. Palpitations were only reported by 10/13 women receiving hexoprenaline. Uterine contractions resumed after 8 minutes (±3) in the atosiban group and 14 minutes (±4) in the hexoprenaline group (P < 0.001).

Conclusion  Atosiban and hexoprenaline were similarly effective for stopping uterine contractions. Women receiving atosiban had significantly fewer adverse events than those receiving hexoprenaline. Uterine contractions resumed more promptly in the atosiban group. Considering the low incidence of mild maternal adverse events, atosiban may be an option for acute intrapartum tocolysis for fetal distress.
For how long should oxytocin be continued during induction of labour?
Authors: Daniel‐Spiegel Etty , Weiner Zeev , Ben‐Shlomo Izhar , Shalev Eliezer
Published: March 2004

Objective  To answer the question of whether oxytocin induction of labour should be discontinued when active labour begins.

Design  We enrolled patients admitted for induction of labour with oxytocin. Exclusion criteria for induction of labour included non‐vertex presentation, past history of more than one caesarean delivery, multiple pregnancies, persistent non‐reassuring fetal heart rate before induction of labour and estimated fetal weight of more than 4250 g.

Setting  Department of Obstetrics and Gynecology, Ha'Emek Medical Center, Afula, Israel.

Population  Patients who were admitted for induction of labour in Ha'Emek Medical Center from 1st February 1998 to 29th February 2000.

Methods  Patients were randomly divided into two groups. In group A, infusion of oxytocin was incremental until 5 cm dilation and maintained at the same level from that point throughout the labour. In group B, infusion of oxytocin was incremental but was discontinued when cervical dilatation reached 5 cm. Comparison between the two groups was made using Wilcoxon rank‐sum test and Fisher's exact test.

Main outcome measure  Primary outcome variable was duration from induction to delivery. The secondary outcome variables included: duration of labour stages, maximal dosage and total amount of oxytocin used, the use of analgesia, abnormalities in fetal heart rate and episodes of uterine hyperstimulation. We also recorded mode of delivery, together with maternal and neonatal outcome.

Results  One hundred and four patients participated in this study. The active phase of labour was shorter in group B compared with group A, but this difference was not statistically significant (2.6 ± 2 vs 3.3 ± 2.9, P= 0.07). In group A there were six caesarean deliveries and in group B only three. No significant differences were found when the other outcome parameters were compared.

Conclusions  There is no advantage in continuing oxytocin infusion after the onset of active labour.
Fetal activin A: associations with labour, umbilical artery pH and neonatal outcome
Authors: Tong Stephen , Egan Val , Wallace Euan M.
Published: March 2004

Objective  To define the ontogeny of umbilical artery activin A at term and to evaluate activin A as a potential marker of perinatal hypoxia.

Design  A cohort study.

Setting  A university teaching hospital delivery suite.

Population  A convenience sample of 141 term pregnancies.

Methods  At delivery, umbilical artery and vein bloods were collected for blood gas measurements and subsequent measurement of activin A. Activin A levels were correlated with blood gas measurements and with labour and neonatal outcomes.

Main outcome measures  Umbilical arterial activin A and pH.

Results  The median (95% CI) umbilical arterial activin A level at delivery was 1.38 (1.34–1.70) ng/mL. Levels varied significantly across gestation (P= 0.03), increasing from 36 to 38 weeks, thereafter decreasing to a nadir at 41 weeks. In 60 matched samples, the median (95% CI) venous and arterial activin A levels were 0.89 (0.81–1.06) ng/mL and 1.38 (1.21–1.61) ng/mL, respectively (P < 0.0001). Mean umbilical arterial pH was 7.20 (7.06–7.38; 5–95th centiles) and was not significantly correlated with log10 activin A (r=− 0.01; P= 0.68). Compared with healthy controls, there was no difference in arterial activin A in neonates identified as having suffered significant intrapartum asphyxia (P= 0.96). Fetal activin A levels were significantly lower in cases delivered by emergency caesarean section for complications during the first stage of labour compared with cases delivered vaginally (P= 0.003).

Conclusions  Umbilical artery activin A does not appear to be a sensitive marker of fetal oxygenation or of risk of hypoxic–ischaemic encephalopathy.
Biologically induced mineralization in the tree Milicia excelsa (Moraceae): its causes and consequences to the environment
Authors: Braissant Olivier , Cailleau Guillaume , Aragno Michel , Verrecchia Eric P.
Published: March 2004

Iroko trees (Milicia excelsa) in Ivory Coast and Cameroon are unusual because of their highly biomineralized tissues, which can virtually transform the trunk into stone. Oxalic acid (C2O4H2) and metal‐oxalate play important roles in their ecosystems. In this study, the various forms of oxalate and carbonate mineralization reactions are investigated by using scanning electron microscopy and X‐ray diffraction. Calcium oxalate monohydrate is associated with stem, bark and root tissues, whereas calcium oxalate dihydrate is found with wood rot fungi in soils, as well as in decaying wood. Laboratory cultures show that many soil bacteria are able to oxidize calcium oxalate rapidly, resulting in an increase in solution pH. In terms of M. excelsa, these transformations lead to the precipitation of calcium carbonate, not only within the wood tissue, but also within the litter and soil. We calculate that c. 500 kg of inorganic carbon is accumulated inside an 80‐year‐old tree, and c. 1000 kg is associated with its surrounding soil. Crucially, the fixation of atmospheric CO2 during tree photosynthesis, and its ultimate transformation into calcite, potentially represents a long‐term carbon sink, because inorganic carbon has a longer residence time than organic carbon. Considering that calcium oxalate biosynthesis is widespread in the plant and fungal kingdoms, the biomineralization displayed by M. excelsa may be an extremely common phenomena.
Evolutionary timing of the origins of mesophilic sulphate reduction and oxygenic photosynthesis: a phylogenomic dating approach
Authors: Blank Carrine E.
Published: March 2004

Until recently, the deep‐branching relationships in the bacterial domain have been unresolved. A new phylogenetic approach (termed compartmentalization) was able to resolve these deep‐branching relationships successfully by using a large number of genes from whole genome sequences and by reducing long branch attraction artefacts. This new, well‐resolved phylogenetic tree reveals the evolutionary relationships between diverse bacterial groups that leave important traces in the geological record. It shows that mesophilic sulphate reducers originated before the Cyanobacteria, followed by the origination of sulphur‐ and pyrite‐oxidizing bacteria after oxygen became available in the biosphere. This evolutionary pattern mirrors a similar pattern in the Palaeoproterozoic geological record. Sulphur isotopic fractionation records indicate that large‐scale bacterial sulphate reduction began in marine environments around 2.45 billion years ago (Ga), followed by rapid oxygenation of the atmosphere about 2.3 or 2.2 Ga. Oxygenation was then followed by increasing oceanic sulphate concentrations (probably owing to pyrite oxidation and continental weathering), which then resulted in the disappearance of banded iron formations by 1.8 Ga. The similarity between the phylogenetic and geological records suggests that the geochemical changes observed on the Palaeoproterozoic Earth were caused by major origination events in the mesophilic bacteria, and that these geochemical changes then caused additional origination events, such as aerobic respiration. If so, then constraints on divergence dates can be established for many microbial groups, including the Cyanobacteria, mesophilic bacteria, mesophilic sulphate reducers, methanotrophs, several anoxygenic phototrophs, as well as for mitochondrial endosymbiosis. These dates may also help to explain a large number of other changes in the geological record of the Neoarchean and Palaeoproterozoic Earth. This hypothesis, however, does not agree with the finding of cyanobacterial and eukaryote lipids at 2.7 Ga, and suggests that further work needs to be done to elucidate the discrepancies in both these areas.
Conceptual models for burrow‐related, selective dolomitization with textural and isotopic evidence from the Tyndall Stone, Canada
Authors: Gingras Murray K. , Pemberton S. George , Muelenbachs Karlis , Machel Hans
Published: March 2004

The formation of dolomite is generally explained using models that reflect larger‐scale processes that describe the relationship between the supply and transport of Mg, and geochemical conditions that are amenable to the formation of dolomite. However, heterogeneities in the substrate, such as those made by bioturbating infauna, may play a more important role in dolomitization than has been previously considered. Burrow‐facilitated dolomitization is evident in the Ordovician Tyndall Stone (Red River Group, Selkirk Formation) of central Canada. The diagenetic fabrics present are attributed to dolomitizing fluids that both flowed through and evolved within burrow networks. Petrographic analysis suggests that two phases of dolomite formation took place. The first formed a fine‐grained, fabric‐destructive type that probably accompanied early burial; the second is a fine‐ to medium‐grained, locally sucrosic dolomite that is interpreted to have precipitated during later burial. Isotopic analysis supports the proposed paragenetic history: (1) an apparent linking of the stable isotopes 13C and 18O strongly suggests that the micrite matrix formed during very early diagenesis and was derived from seawater; (2) the initial phase of dolomitization is potentially microbially mediated, as evidenced by the enrichment of 13C; and (3) isotopic values for the second generation of dolomite reflect the mixing of ground water and resorbed early dolomite. This paper conceptualizes the physical and chemical conditions required for the formation of dolomite in association with burrow fabrics. The proposed model reveals a composite of biological and inorganic reactions that demonstrates the interdependence of sediment fabric, organic content and microbial interactions in the development of burrow‐mottled dolomitic limestone. It is suggested that where burrow‐associated dolomite occurs, it is most likely to develop in two stages: first, the byproducts of the degradation of organic material in burrows locally increase the permeability and porosity around burrow fabrics in shallow diagenetic depositional environments; and, second, the passing of burrowed media into deeper dysaerobic sediment is accompanied by the establishment of fermenting micro‐organisms whose byproducts mediate dolomitization.
Influence of Age on Atrial Fibrillation Inducibility
Authors: BREMBILLA‐PERROT BÉATRICE , BURGER GUILLAUME , BEURRIER DANIEL , HOURIEZ PIERRE , NIPPERT MARC , MILJOEN HIELKHO , ANDRONACHE MARIUS , KHALDI EMAD , POPOVIC BATRIK , DE LA CHAISE ARNAUD TERRIER , LOUIS PIERRE
Published: March 2004

The prevalence of AF is known to increase in the elderly. Some electrophysiological changes were reported in these patients, but the effects of age on AF inducibility and other electrophysiological signs associated with atrial vulnerability are unknown. The purpose of the study was to evaluate the effects of age on atrial vulnerability and AF induction. The study consisted of 734 patients (age 16–85 years, mean 61 ± 15 years) without spontaneous AF who were admitted for electrophysiological study. Study was indicated for dizziness or ventricular tachyarrhythmia. Programmed atrial stimulation was systematically performed. One and two extrastimuli were delivered in sinus rhythm and atrial driven rhythms (600, 400 ms). Univariate and multivariate analysis of several clinical and electrophysiological data were performed. AF inducibility, defined as the induction of an AF lasting > 1 minute, was paradoxically and significantly decreased in elderly (> 70 years) patients compared to younger patients (< 70 years) (P < 0.01). AF inducibility was present in 40% of 62 patients < 40 years, 39% of 99 patients age 40–50 years, 37% of 130 patients age 50–60 years, 38% of 222 patients age 60–70 years, and only 28% of 221 patients > 70 years. There was no significant correlation with the sex, the presence of dizziness, the presence or not of an underlying heart disease, the left ventricular ejection fraction, and the presence of salvos of atrial premature beats on 24‐hour Holter monitoring. There was a significant correlation with a longer atrial effective refractory period in the elderly (226 ± 41 ms) than in younger patients (208 ± 31 ms) (P < 0.001). Other electrophysiological parameters of atrial vulnerability did not change significantly. Increased atrial refractory period and age >70 years were independent factors of decreased AF inducibility. Programmed atrial stimulation should be interpreted cautiously before the age of 70 years. AF induction is facilitated by the presence of a short atrial refractory period in these patients. Surprisingly, AF inducibility decreases in patients > 70 years because their atrial refractory period increases. Therefore, increased AF prevalence in these patients should be explained by nonelectrophysiological causes. (PACE 2004; 27:287–292)
Application of Radiofrequency Energy in Surgical and Interventional Procedures:
Authors: FIEK MICHAEL , DORWARTH UWE , DURCHLAUB ILKA , JANKO SABINE , BARY CHRISTIAN VON , STEINBECK GERHARD , HOFFMANN ELLEN
Published: March 2004

During surgical and interventional procedures, interference may occur between ICDs and electrical cautery or with the application of RF energy. This may lead to the false induction of ICD therapies or could even result in device malfunction, which represents a potential perioperative hazard for the patient. This study analyzed the intraoperative interactions in 45 consecutive ICD patients in reference to different surgical and interventional procedures. A total of 33 surgical operations (general surgery [n = 14], urologic [n = 5], abdominal [n = 10], gynecological [n = 2], thoracic [n = 1], neurosurgical [n = 1]) and 12 interventional therapies (RF catheter ablation [n = 10], endoscopic papillotomy [n = 2]) were performed. The ICD devices were all located in left pectoral position and consisted of 25 single and 20 dual chamber defibrillators. During the procedure, tachyarrhythmia detection (VF 296 ± 20 ms, VT 376 ± 49 ms) of the devices was maintained active (monitoring mode), only ICD therapies were inactivated. The indifferent electrode of the electrical cauter/RF generator was placed in standard positions (right/left mid‐femoral position [n = 27/8], thoracic spine area [n = 10]). After the procedure, the ICD memory was checked for detections and for changes in the programming. There was no oversensing, reprogramming, or damage of any defibrillator caused by RF energy. Despite the lack of undesired interactions, ICDs should be inactivated preoperatively to assure maximum patient safety. However, should inactivation not be possible, or the achievement uncertain, electromagnetic interference is highly unlikely. (PACE 2004; 27:293–298)
Heart Rate Variability and Diastolic Heart Failure
Authors: ARORA RISHI , KRUMMERMAN ANDREW , VIJAYARAMAN PUGAZHENDIHI , ROSENGARTEN MICHAEL , SURYADEVARA VANA , LEJEMTEL THIERRY , FERRICK KEVIN J.
Published: March 2004

Diastolic heart failure accounts for up to 40% of patients with congestive heart failure (CHF), and is associated with a better prognosis as compared to patients with systolic dysfunction. Nevertheless, patients with diastolic dysfunction have a significantly higher mortality as compared to the normal population. Reduced heart rate variability (HRV), a marker of autonomic dysfunction, is associated with increased mortality in patients with systolic heart failure. We therefore sought to determine to what extent HRV is altered in a population of patients with diastolic heart failure. Twenty‐four hour ambulatory (Holter) recordings were performed in 19 consecutive patients with diastolic heart failure, in 9 patients with systolic heart failure, as well as in 9 healthy volunteers (normal controls). Time and frequency domain HRV variables were obtained for all three groups of patients. Both Time and Frequency domain variables were found to be reduced in both heart failure groups compared to normal controls. When compared with each other, patients with diastolic function had relatively higher values of HRV variables, compared to those with systolic dysfunction (SDNN, Total power, ULF power, all P ≤ 0.05). Patients with diastolic dysfunction have reduced HRV, suggesting a disturbed sympathetic‐parasympathetic balance. Nevertheless, values for HRV are not as profoundly reduced as in patients with systolic dysfunction. The relative preservation of sympathetic‐parasympathetic balance may explain the better prognosis in this patient population. (PACE 2004; 27:299–303)
QRS Duration and Shortening to Predict Clinical Response to Cardiac Resynchronization Therapy in Patients with End‐Stage Heart Failure
Authors: MOLHOEK SANDER G. , BAX JEROEN J. , BOERSMA ERIC , ERVEN LIESELOT VAN , BOOTSMA MARIANNE , STEENDIJK PAUL , VAN DER WALL ERNST E. , SCHALIJ MARTIN J.
Published: March 2004

Despite current selection criteria (NYHA Class III–IV, LVEF < 35%, QRS > 120 ms with LBBB), 30% of patients do not benefit from cardiac resynchronization therapy (CRT). The use of QRS duration as selection criteria for CRT has not been evaluated systematically yet. Accordingly, the value of QRS duration at baseline (and reduction in QRS duration after CRT) to predict responders was studied. Patients were evaluated at baseline and after 6 months of CRT for NYHA Class, quality of life score, and 6‐minute walk test. QRS duration was evaluated before, directly after implantation, and after 6 months of CRT. Sixty‐one patients were included; 45 (74%) patients were classified as responders (improvement of NYHA Class, 6‐minute walking distance and quality of life score) and 16 (26%) as nonresponders. QRS duration at baseline was similar between the two groups: 179 ± 30 ms versus 171 ± 32 ms, NS. Directly after implantation, QRS duration was reduced from 179 ± 30 ms to 150 ± 26 ms (P < 0.01) in responders; nonresponders did not exhibit this reduction (171 ± 32 ms vs 160 ± 26 ms, NS). After 6 months of CRT, QRS shortening was only observed in responders (from 179 ± 30 ms to 159 ± 25 ms, P < 0.01). ROC curve analysis showed that a reduction in QRS duration > 10 ms had a high sensitivity (73%) with low specificity (44%); conversely, a > 50 ms reduction in QRS duration was highly specific (88%) but not sensitive (18%) to predict response to CRT. No optimal cutoff value could be defined. QRS duration at baseline is not predictive for response to CRT; responders exhibit a significant reduction in QRS duration after CRT, but individual response varies highly, not allowing adequate selection of responders. (PACE 2004; 27:308–313)
Permanent Left Atrial Pacing:
Authors: MIRZA INTISAR , JAMES SIMON , HOLT PHYLLIS
Published: March 2004

Left atrial pacing is feasible via the coronary sinus. However, long‐term characteristics of coronary sinus pacing parameters are largely undefined as yet. This study assessed the feasibility and long‐term pacing parameters of coronary sinus pacing. Twenty four patients (13 men, 11 women) with a history of paroxysmal AF refractory to drug therapy underwent biatrial pacemaker implantation. Leads were sited in the high right atrium or right atrial appendage and in either proximal (PCS) or distal coronary sinus (DCS). Pacemaker parameters were measured at implant, 24 hours postimplant, 1 month, 3 months, and at 3 monthly intervals over a period of 2 years. Threshold, impedance, and energy requirements (E = Threshold2/impedance x pulse width) were measured. There was one lead displacement from the PCS within 24 hours postimplant. There were no other acute or chronic complications. The energy values at implant and at 2 years were 0.49 ± 0.47 and 2.18 ± 1.69 mJ for the PCS leads and 0.94 ± 1.47 and 1.27 ± 0.75 mJ for the DCS leads. P values were >0.05 at all points and suggested no significant difference between the two sites over the long‐term. Chronic coronary sinus pacing is a safe and feasible technique. There was no significant difference in energy parameters for leads positioned in the proximal or distal coronary sites. The trends seen at both sites for chronic changes in pacing characteristics are analogous to those described for endocardial leads at other sites. (PACE 2004; 27:314–317)
Dofetilide Effects on the Inhibition by Trains of Subthreshold Conditioning Stimuli
Authors: CHORRO FRANCISCO J. , FERRERO ANGEL , SAIZ JAVIER , SANCHIS JUAN , PORRES JUAN C. , MAINAR LUIS , CÁNOVES JOAQUIN , BLASCO ESTRELLA , LÓPEZ‐MERINO VICENTE , SUCH LUIS
Published: March 2004

We investigated the electrophysiological actions of dofetilide upon the ventricular myocardium to determine whether the drug modifies the inhibitory effects of subthreshold stimuli trains upon ventricular refractoriness. In nine Langendorff perfused rabbit hearts, ventricular epicardial electrodes were used to determine the following parameters at baseline and during dofetilide perfusion (0.5 micromolar): effective (ERP) and functional (FRP) refractory periods, conduction velocity (CV), wavelength (WL), and ERP prolongation (inhibitory effect) induced by subthreshold stimuli trains (STr) at pulse frequencies of 100, 300, and 600 Hz. Dofetilide significantly prolongs ventricular refractoriness and WL: ERP increment (Dofetilide‐baseline, 300 ms cycle length) = 33 ± 20 ms (24 ± 12%, P < 0.01); FRP increment = 37 ± 19 ms (23%± 10%, P < 0.01); WL increment = 4.1 ± 3.2 cm (27%± 20%, P < 0.01), without modifying CV. These effects are diminished upon increasing the stimulation frequency: ERP increment (Dofetilide‐baseline, 150 ms cycle length) = 18 ± 10 ms (18%± 12%, P < 0.05); FRP increment = 15 ± 4 ms (14%± 5%, P < 0.01); WL increment = 1.9 ± 1.7 cm (18%± 10%, P < 0.01). The STr significantly prolong ERP, and the increments obtained at baseline and during dofetilide perfusion are similar. In both cases the inhibitory effect is slight for STr of 100 Hz (baseline = 5 ± 3 ms, dofetilide = 6 ± 5 ms, with nonsignificant (ns) differences between them) and highly manifest for STr of 300 Hz (baseline = 76 ± 33 ms, dofetilide = 87 ± 32 ms, ns) and 600 Hz (baseline = 109 ± 39 ms, dofetilide = 89 ± 34 ms, ns). Dofetilide prolongs ventricular refractoriness and WL, exerting a reverse‐frequency dependent effect without modifying CV. The inhibitory effect of STr is greater when their pulse frequency is increased, and its magnitude is similar under the influence of dofetilide. During dofetilide perfusion the inhibitory effect of STr adds to the ERP prolongation induced by the drug. (PACE 2004; 27:327–332)
Sequential Biventricular Pacing:
Authors: MORTENSEN PETER T. , SOGAARD PETER , MANSOUR HASSAN , PONSONAILLE JEAN , GRAS DANIEL , LAZARUS ARNAUD , REISER WOLFGANG , ALONSO CHRISTINE , LINDE CECILIA M. , LUNATI MAURIZIO , KRAMM BERTHOLD , HARRISON E. MARK
Published: March 2004

The study evaluated the clinical safety, performance, and efficacy of sequential biventricular pacing in the InSync III (Model 8042) biventricular stimulator in a multicenter, prospective 3‐month study and assessed the proper functioning of features aiming at improving biventricular AV therapy delivery. The system was successfully implanted in 189 (95.9%) of 198 patients with symptomatic systolic heart failure and a prolonged QRS complex duration. Patients significantly improved their 6‐minute hall walk distance (baseline 339 ± 92 vs 3‐month 422 ± 127 meter, P < 0.001) and NYHA class (baseline 3.1 ± 0.5 vs 3‐month 1.9 ± 0.7, P < 0.001). Echocardiographic optimization of sequential biventricular pacing showed an improvement in stroke volume compared to simultaneous stimulation (sequential 68 ± 24 mL vs simultaneous 56 ± 23 mL, P < 0.001) at baseline and at 3 months. In 88% (30/34) of the patients these improvements were seen within a small range of V‐V delays of ±20 ms and in 94% (32/34) within V‐V delays of ±40 ms. In contrast, programming beyond this range reduced stroke volume below that during simultaneous biventricular pacing. The device functioned as expected. LV lead dislodgement was observed in 12 patients and phrenic nerve stimulation required lead repositioning in 2 patients. Eight patients died during the study. Patient survival at 3 and 6 months was 97 ± 2% and 94 ± 2%, respectively. Cause of death was cardiac (n = 7), heart failure related (n = 3), arrhythmia related (n = 2), and unknown (n = 2). In conclusion, this sequential biventricular pacemaker was safe and efficacious. (PACE 2004; 27:339–345)
Addition of a Defibrillation Electrode in the Low Right Atrium to a Right Ventricular Lead Does Not Reduce Ventricular Defibrillation Thresholds
Authors: RÜB NORMAN , DOERNBERGER VOLKER , SMITS KAREL , SCHWEITZER OLIVER , MEWIS CHRISTIAN , KETTERING KLAUS , KUEHLKAMP VOLKER
Published: March 2004

Transvenous unipolar active can defibrillation systems have proven to be effective in treating ventricular tachyarrhythmias. However, a further reduction of ventricular defibrillation thresholds (V‐DFT) would increase the longevity, reduce the size of pulse generators, and help to avoid additional leads in patients with inacceptable high V‐DFTs. In a finite difference computer model, the extension of the right ventricular (RV) defibrillation coil into the low right atrium led to a 40% reduction of unipolar V‐DFT. To evaluate this finding, we conducted a prospective, randomized study in 11 patients receiving an ICD. Extension of the RV electrode was simulated by adding a second coil placed in the low right atrium with the same polarity. Using a binary search protocol, V‐DFT was determined with and without the additional electrode in each patient. Total shock impedance was significantly lower in the two coil (low RA) configuration, compared to the single coil (RV) configuration. Corresponding values were 49.9 ± 6.7 Ohm and 61.1 ± 9.3 Ohm, respectively (P < 0.01, paired t‐test). However, there was no reduction, but even a nonsignificant increase in V‐DFTs. Mean V‐DFT in the RV configuration was 12.0 ± 5.6 J and 16.3 ± 7.8 J in the low RA configuration (P = 0.09, paired t‐test). Despite a reduction in total impedance, the addition of a defibrillation coil in the low right atrium does not reduce ventricular defibrillation thresholds. (PACE 2004; 27:346–351)
Incidence of Postdischarge Symptomatic Paroxysmal Atrial Fibrillation in Patients Who Underwent Coronary Artery Bypass Graft:
Authors: ANTONELLI DANTE , PERES DIMITRI , FREEDBERG NAHUM ADAM , FELDMAN ALEXANDER , ROSENFELD TIBERIO
Published: March 2004

The aim of this retrospective study was to determine the incidence of symptomatic AF of patients who had undergone coronary artery bypass grafting (CABG) during long‐term follow‐up. The study population included 305 post‐CABG patients who were regularly followed in the outpatient clinic. Paroxysmal AF (PAF) was defined as an episode of symptomatic AF when symptoms were prolonged enough for the patient to request medical care. Perioperative AF occurred in 88 (28.9%) patients. Postdischarge symptomatic PAF occurred in 25 (8.2%) patients with an annual incidence of 2% during a mean follow‐up of 48 ± 30 months. Eighteen (20.4%) patients also experienced perioperative AF with an annual incidence of 5.1%, while only 7 (3.2%) of 217 patients, without perioperative AF, had postdischarge AF (P < 0.0003). During long‐term follow‐up, postdischarge AF has a low incidence and prophylactic antiarrhythmic therapy is not recommended. The method of follow‐up and retrospective analysis may understate PAF and even miss some symptomatic episodes. Perioperative AF is a predictor of symptomatic late PAF recurrences, particularly in patients with reduced left ventricular function. (PACE 2004; 27:365–367)
Effects of Pretreatment with Intravenous Flecainide on Efficacy of External Cardioversion of Persistent Atrial Fibrillation
Authors: CLIMENT VICENTE E. , MARÍN FRANCISCO , MAINAR LUIS , GÓMEZ‐ALDARAVÍ RICARDO , MARTÍNEZ JUAN GABRIEL , CHORRO FRANCISCO J. , ROMÁN PILAR , SOGORB FRANCISCO
Published: March 2004

Electrical cardioversion is the most effective and safe method to restore sinus rhythm in patients with persistent AF. However, at least 25% of electrical cardioversions are unsuccessful. The aim of the present study was to evaluate, in a prospective, randomized and double‐blind study, the efficacy of a pretreatment with intravenous flecainide in patients who underwent electrical cardioversion. Fifty‐four consecutive patients with persistent AF, mean arrhythmia duration 8 (mean 3–18) weeks, were randomized in two groups. In the first group (n = 26), patients received flecainide (2 mg/kg as a 30‐minute IV infusion) before electrical cardioversion. In the second group (n = 28), 100 mL IV infusion of 5% glucose was administered 30 minutes before electrical cardioversion. The study evaluated the (1) acute efficacy of electrical cardioversion, (2) mean and maximal energy required, (3) mean number of shocks needed, and (4) incidence of complications. The two groups were similar in terms of age, sex, mean AF duration, left ventricular systolic function, atrial dimension, and cardiovascular risk factors. Seventy‐seven percent of patients recovered sinus rhythm with electrical cardioversion. No statistical difference was noted between the two groups: flecainide 19/26 (73%) versus placebo 23/28 (82%). No significant differences were found concerning mean or maximal energy and number of shocks required. No major complications were observed. After a 30‐day follow‐up, 54% of patients maintained sinus rhythm with no difference between the two groups. Pretreatment with intravenous flecainide before electrical cardioversion is not useful in reducing technical failure of cardioversion, however, flecainide does not diminish the effectiveness of electrical cardioversion. (PACE 2004; 27:368–372)
Radiofrequency Catheter Ablation of an Accessory Pathway in a Patient with Wolff‐Parkinson‐White and Kartagener's Syndrome
Authors: STERNICK EDUARDO BACK , MÁRCIO GERKEN LUIZ , MAX ROBERTO , OSVALDO VRANDECIC MÁRIO
Published: March 2004

We report a case of a manifest left free wall accessory pathway in a patient with Kartagener's syndrome and recurrent episodes of orthodromic atrioventricular reentrant tachycardia. To the best of our knowledge, it is the first report of Wolff‐Parkinson‐White syndrome associated with Kartagener's syndrome. Situs inversus and mirror image dextrocardia occurred with no additional detectable cardiac structural abnormalities. Diagnostic and therapeutic electrophysiological study was carried out via transaortic approach and a left‐to‐right reversal of monoplane fluoroscopic image. (PACE 2004; 27:401–404)
Malfunction of the Automatic Slope Adjustment of the QT Sensor in Patients with Normal QT Intervals
Authors: RUITER JACOB H. , BARRETT MICHAEL J. , WETELING LOES , JANSEN RIK
Published: March 2004

DDDR pacemakers with QT driven sensor algorithms may be susceptible to inappropriate pacemaker tachycardia when implanted into patients who have a relatively extended cardiac repolarization. The inability to detect and measure the QT interval at near maximum sensor rate, results in an inappropriate adjustment of the automatic QT slope. Triggering pacemaker induced tachycardia. (PACE 2004; 27:405–407)