bluuebunny/crossref_metadata_2025 huggingface dataset:
Brain temperature in newborn piglets under selective head cooling with minimal systemic hypothermia
Authors: Iwata Osuke , Iwata Sachiko , Tamura Masanori , Nakamura Tomohiko , Sugiura Masatoshi , Ogiso Yoshifumi
Published: May 2003

Abstract
Background:
Although selective brain hypothermia is expected to be a promising neuroprotective treatment, the thermal distribution under hypothermia is not fully investigated. We applied selective head cooling to seven newborn piglets under general anesthesia in order to investigate the mechanism of cooling.

Methods:
Seven healthy, large white piglets aged within 5 days after birth were studied. Temperatures were monitored at the superficial brain (0.5 cm), deep brain (2.0 cm), scalp skin, nasopharynx, tympanum, esophagus, and rectum. A radiant heater and a warmer blanket were used to maintain the normal rectal temperature (38.5−39°C). For the first piglet, the coolant temperature was widely changed from 15C to − 20C in order to define the practical range. Subsequently, the coolant temperature was set at 10C, 0C, and − 10C for the remaining six piglets. The target deep brain temperature was set at 35C, as the same reduction of brain temperature might provide moderate brain hypothermia in the human neonate.

Results:
With 0C coolant temperature, the deep brain temperature was cooled to 35C; however, the scalp skin attached to the cooling cap became broadly blotchy and injured in all animals. When we induced minimal systemic hypothermia by 1C for a cohort of three piglets, the deep brain temperature decreased in parallel with the rectal temperature, which enabled us to achieve the target temperature with 10°C coolant without injuring the scalp skin. The scalp skin and nasopharyngeal temperatures were good predictors of both superficial and deep‐brain temperatures throughout the experiment.

Conclusions:
Our results suggest that moderate brain hypothermia may be applied to newborn infants without inducing moderate systemic hypothermia.
Factor VIII levels in children with thrombosis
Authors: Kurekci A Emin , Gokce Hafize , Akar Nejat
Published: May 2003

Abstract
Background
: A number of coagulation defects have been implicated as risk factors in thrombo‐embolic disease. Of these, high levels of clotting factor VIII have been shown to be associated with a five‐ to six‐fold increased risk of thrombosis, compared to levels < 100 IU/dL in adults. The objective of this study was to investigate the prevalence of elevated plasma levels of factor VIII in a pediatric population with thrombo‐embolism (TE).

Methods:
 Forty‐two children (17 female, 25 male) with TE and 165 healthy controls without familial history of thrombosis or stroke were included in the present study. Doppler ultrasonography with or without angiography, computed tomography, magnetic resonance imaging or echocardiography was utilized to establish the diagnosis. One‐stage clotting assay with factor VIII‐deficient plasma for measurement of factor VIII and immunoturbidometric assay for von Willebrand factor (vWF) levels were utilized. All measurements were performed in duplicate. Plasma levels of factor VIII were assessed in parents of nine patients to establish whether high levels of factor VIII were genetically determined.

Results
: The median age at onset of TE was 7 years (range 0−17 years). Among patients with TE compared to controls, the prevalence of high factor VIII levels was 59.5% versus 12.1% (odds ratio 10.6, 95% CI: 4.9−23.1). The prevalence of high factor VIII levels was detected in at least one of nine families.

Conclusion:
 The data in the present study provide evidence that elevated plasma factor VIII levels are associated with increased risk of thrombosis in children: thus, plasma concentration of factor VIII should be measured in all children with TE.
Inducible and endothelial constitutive nitric oxide synthase gene polymorphisms in Kawasaki disease
Authors: Khajoee Vahid , Kariyazono Hidehiko , Ohno Takuro , Ihara Kenji , Mizuno Yumi , Kusuhara Koichi , Hara Toshiro
Published: May 2003

Abstract
Background
: Nitric oxide (NO) is secreted by immune and vascular endothelial cells, and appears to play important roles in the pathophysiology of Kawasaki disease (KD). Thus, genetic variations in NO synthase (NOS) genes may be involved in the development of coronary artery lesions (CAL) in KD.

Methods
: The present study investigated the association of endothelial constitutive NOS (ecNOS) and inducible NOS (iNOS) gene polymorphisms with the development of CAL in KD in a Japanese population.

Results
: The genotype distributions of 27‐bp tandem repeat polymorphism within intron 4 of ecNOS gene did not show any significant difference between controls and KD patients with or without CAL. In addition, there was no significant association between whole‐allele distribution of iNOS gene promoter (penta‐repeat CCTTT) polymorphism and KD with or without CAL.

Conclusion
: These results did not support any association of ecNOS and iNOS gene polymorphisms to the development of CAL in KD patients in a Japanese population.
Effect of Trp64Arg mutation of the β3‐adrenergic receptor gene and C161T substitution of the peroxisome proliferator activated receptor γ gene on obesity in Japanese children
Authors: Arashiro Rina , Katsuren Keisuke , Fukuyama Shigeru , Ohta Takao
Published: May 2003

Abstract
Objective:
Obesity is a multifactorial syndrome influenced by both genetic and behavioral factors. Trp64Arg mutation of the β3‐adrenergic receptor (AR) gene and C161T substitution of the peroxisome proliferator‐activated receptor (PPAR) γ gene have been reported to be associated with obesity or lipid metabolism in adults. However, the effects of these mutations on children have not yet been clarified. For this reason, we studied the effects of Trp64Arg mutation of the β3‐AR gene and C161T substitution of the PPARγ gene on obesity in Japanese children.

Subjects and Methods:
In order to determine the effects of Trp64Arg mutation of the β3‐AR gene and C161T substitution of the PPARγ gene on obesity in children, 105 obese Japanese children were screened by the polymerase chain reaction and restriction fragment‐length polymorphism analysis. Plasma lipid, apolipo­protein (apo), glucose, insulin and leptin levels were also determined.

Results:
Obese boys with Trp64Arg showed a higher obesity index and lower plasma levels of high‐density lipoprotein cholesterol (HDL‐C), apoA‐I and apoA‐II than those of them without the mutation. Obese boys with both mutations showed a higher plasma leptin level than those with only the β3‐AR gene mutation or PPARγ gene mutation. No significant effect of these mutations was found in obese girls.

Conclusion:
All of these data suggest that Trp64Arg mutation of the β3‐AR gene might affect obesity and HDL metabolism in obese boys. In contrast, C161T mutation of the PPARγ gene, by itself, is unlikely to influence obesity, lipid metabolism or plasma leptin levels.
Body fat ratios in urban Chinese children
Authors: Iwata Fujihiko , Hara Mitsuhiko , Okada Tomoo , Harada Kensuke , Li Shilian
Published: May 2003

Abstract
Objective
: As obesity has been increasing in China, the present study examined the body composition of children to assess their fatness.

Study design
: A total of 532 healthy schoolchildren who lived in central Beijing were examined. Skinfold thicknesses, hip and waist circumferences, and body fat percentage were measured, as well as height and weight.

Results
: The prevalence of overweight (Body Mass Index (BMI) ≥ 95% for age and sex of Chinese children) was 27.7% in boys and 14.2% in girls (chi‐squared; P = 0.0001). The percentages of body fat (BF%), waist/hip ratios and skinfold thicknesses ratios (subscapular/triceps) in overweight children were significantly higher than those in non‐overweight children (Mann−Whitney U‐test). The BF% of non‐overweight boys was significantly higher than that of non‐overweight girls.

Conclusion
: Urban Chinese overweight children have high BF% with adverse fat distribution. They may have high risk of atherogeniety. Boys in the non‐overweight category may have higher fat accumulation than predicted by BMI. The establishment of an intervention program for childhood obesity is strongly recommended.
Effects of childhood bronchiectasis on cardiac functions
Authors: Akalin Figen , Koroglu Tolga F , Bakac Serap , Dagli Elif
Published: May 2003

Abstract 
Background
: Bronchiectasis is still a widespread disease in developing countries. It is an important cause of mortality and morbidity. The information on cardiac involvement in bronchiectasis is limited. However, cor pulmonale is common in patients with chronic lung disease, such as cystic fibrosis.

Methods: 
We utilized echocardiography and exercise tests, along with clinical scoring, chest radiograph scoring, and pulmonary function tests in 21 patients to determine whether detectable changes in cardiac functions were present, and the nature of their relationship to the underlying disease severity.

Results: 
The ventricular systolic functions were preserved in all patients. Some of the patients had changes in left ventricular diastolic function indices, characterized by abnormal Ewave/Awave (E/A) ratios or isovolumetric relaxation time values. Isovolumetric relaxation time but not E/A ratios was found to have a significant negative correlation with the clinical score. In addition, exercise capacity was decreased in bronchiectatic children. Most of the patients stopped the exercise test due to exhaustion before reaching maximum heart rate.

Conclusion
: Left ventricular diastolic functions are affected in bronchiectasis, and the performance of patients is dependent on their pulmonary status. This is the first study demonstrating the cardiac effects of bronchiectasis according to our survey of the published literature.
Associated features of conversion disorder in Turkish adolescents
Authors: Ercan Eyüp S , Varan Azmi , Veznedaroğlu Baybars
Published: May 2003

Abstract
Background
: Conversion disorder in adolescents has not been studied extensively. A limited number of studies have focused on the features related to conversion disorder in adolescents. However, most of these studies used either retrospective data or did not have a control group that would allow comparison with the index cases.

Methods
: Fifty‐two Turkish adolescent patients diagnosed with conversion disorder were compared with a control group of 52 adolescents diagnosed with psychiatric disorders other than conversion disorder. The data were collected from the adolescent subjects and their mothers by various questionnaires, inventories, and psychiatric interviews.

Results
: In the present study, pseudoseizures were the most common subtype of conversion disorder, followed by motor symptoms or deficits. Coming from a rural area, having a broken family, long‐term separation from parents, problems related to communication and expression of emotions in the family, higher anxiety scores, conversion disorder in the proximal environment, and conversion disorder or other psychiatric disorders in the mother were significantly associated with conversion disorder in adolescents.

Conclusions
: The findings of the present study are in accordance with existing findings, and amplify the importance of problems in family functioning in the etiology of conversion disorder.
Microbiology and management of intra‐abdominal infections in children
Authors: Brook Itzhak
Published: May 2003

Abstract The present review describes the microbiology, diagnosis, and management of intra‐abdominal infections in children. Infection generally occurs due to the entry of enteric micro‐organisms into the peritoneal cavity through a defect in the wall of the intestine or other viscus as a result of obstruction, infarction, or direct trauma. Mixed aerobic and anaerobic flora can be recovered from the peritoneal cavity of these patients. The predominant aerobic isolates are Escherichia coli, and enterococci; the main anaerobic bacteria are Bacteroides fragilis group, Peptostreptococcus spp. and Clostridium spp. The treatment of abdominal infection includes surgical correction and drainage, and administration of antimicrobials that are effective against both aerobic and anaerobic micro‐organisms.
Neonatal toxic shock syndrome‐like exanthematous disease (NTED)
Authors: Takahashi Naoto
Published: May 2003

Abstract The author and colleagues recently discovered an emerging neonatal infectious disease: neonatal toxic shock syndrome‐like exanthematous disease (NTED), which is induced by the superantigen toxic shock syndrome toxin‐1 (TSST‐1), produced by methicillin‐resistant Staphylococcus aureus (MRSA). The massively expanded Vβ2+ T cells were rapidly deleted in the peripheral blood of patients with NTED. A marked depletion of Vβ2+ T cells was also observed in the peripheral blood before the expansion of these T cells. Anergy is specifically induced in the TSST‐1 reactive T cells of patients with NTED. Rapid recovery from NTED without complications is expected to be related to the induction of immunologic tolerance in neonatal patients. Anti‐TSST‐1 IgG antibody of maternal origin was found to play a protective role in preventing the development of NTED. The number of hospitals that have experience caring for patients with NTED has increased threefold in the past 5 years. Most MRSA isolates from neonatal intensive care units in Japan were found to be a single clone of coagulase type II and to possess TSST‐1 and staphylococcal enterotoxin C genes. The timing and increased incidence of NTED suggest the emergence of a new MRSA clone. By recognizing that TSST‐1 can induce NTED, healthcare providers may give increased attention to this disease in neonatal wards.
Prevention of methicillin‐resistant Staphylococcus aureus infections in neonates
Authors: Kitajima Hiroyuki
Published: May 2003

Abstract Reports of methicillin‐resistant Staphylococcus aureus (MRSA) infection in neonatal intensive care units (NICU) and normal newborn nurseries in Japan were investigated, and various methods of preventing transmission were evaluated.

In the late 1980s, MRSA which had spread in adult wards also invaded NICU. Very low birthweight or premature infants had become the targets of MRSA infection and this has now become a serious problem. Recent reports have revealed that 87% of major NICU in Japan have suffered from MRSA infections. However, we have found that preventive measures can greatly reduce the risk of a newborn being infected by a carrier, while also controlling the disease caused by MRSA infection. Recently, MRSA infections in normal newborn nurseries have also become a serious problem in pediatric departments. Methicillin‐resistant Staphylococcus aureus which can colonize in the newborn baby just after birth, is passed on to the newborn by carrier medical staff. It was found to be of great importance that infant's mothers hold and nurse their babies immediately after birth, and start breast‐feeding while still in the delivery room. Furthermore, the most appropriate and ideal newborn nursery is one where mother and child are roomed together and there is little intervention by the hospital. In neonatal care, it is of utmost importance to treat carriers of MRSA bacteria, and to inhibit the spread of the bacterium in babies by taking standard precautionary measures.
Genetic basis of neonatal methicillin‐resistant Staphylococcus aureus in Japan
Authors: Kikuchi Ken
Published: May 2003

Abstract Methicillin‐resistant Staphylococcus aureus (MRSA) is still one of major problems of drug‐resistant microorganisms and healthcare‐acquired infections. Methicillin‐resistant Staphylococcus aureus is highly prevalent in patients in neonatal intensive care units (NICU) in Japan. The most predominant MRSA in NICU is multidrug resistant and produces superantigenic exotoxin, toxic shock syndrome toxin−1 (TSST−1) and staphylococcal enterotoxin C (SEC). These predominant MRSA strains belong to coagulase type II, SCCmec type II, mecA‐Tn554 polymorph type I‐A and show closely related pulse field gel electrophoresis types. The dissemination of MRSA is wide, and there is a pandemic distribution of a single MRSA clone in the NICU of Japan. Since 1992, the nationwide spread of this clone has also led to the development of a new neonatal disease known as neonatal toxic shock‐like exanthematous disease (NTED), which is caused by overactivation of vβ2+ T cells induced by TSST−1.

The spread of MRSA in NICU in Japan has been attributed to overcrowding, high rates of extremely low birthweight babies, understaffing, low control measures of infection and overuse of antibiotics. The environment of NICU and infection control intervention should be improved and a new strategy for control like vaccination or probiotics is required.
Examination of severe, hospital acquired infections affecting extremely low birthweight (ELBW) infants
Authors: Usukura Yukihiro , Igarashi Takeyasu
Published: May 2003

Abstract
Purpose
: A nationwide questionnaire survey was carried out in 77 major neonatal intensive care unit (NICU) facilities in Japan. The survey investigated severe, hospital acquired infections occurring in extremely low birthweight (ELBW) infants at each institution.

Methods
: The nationwide questionnaire survey involved 77 major NICU facilities and ELBW infants born in 1996. The actual status of severe infection in these infants was investigated.

Results
: Replies were obtained from 57 of the 77 facilities that were sent a questionnaire (74% recovery). During the survey period, the total number of patients hospitalized in 57 facilities was 13 697, of which there were 836 ELBW infants. During this period, severe infection occurred in 126 of the ELBW infants. Of those, 98 who developed delayed infection (72 h or more after birth) on the basis of the date of onset were investigated. Methicillin‐resistant staphylococcus aureus (MRSA) was the most common organism found, (38 infants, 38.8%), followed by Pseudomonas (10 infants, 10.2%) and Candida (8 infants, 8.2%). Septicemia was present in 67 patients (68.4%), while pneumonia and gastrointestinal complications were found in 15 patients (15.3%). With respect to therapy, the selection of antibiotics varied between facilities. Vancomycin (VCM) was used in 31 cases (31.6%) because MRSA was the most common organism. VCM was used from the early stage of treatment in as many as 20 infants (20.4%). Fifty‐eight infants survived (59.2%), 28 infants died (28.6%), and 12 subsequentally had obvious complications (12.2%).

Conclusion
: It was confirmed that severe, hospital acquired infections caused by MRSA are still a significant problem in many institutions. Despite active prevention and treatment, the incidence of severe, hospital acquired infection has not decreased and the prognosis has not improved. Considering the inadequacy of the medical care environment in Japan, it seems impossible to solve these problems at present.
Atrial Activation Analysis by Surface P Wave and Multipolar Esophageal Recording After Cardioversion of Persistent Atrial Fibrillation
Authors: BAGLIANI GIUSEPPE , MICHELUCCI ANTONIO , ANGELI FABIO , MENICONI LUIGI
Published: May 2003

We studied atrial activation during sinus rhythm by combining 12‐lead ECG and multipolar esophageal recordings in 30 patients after electrical cardioversion of persistent atrial fibrillation. The primary endpoint was to establish a correlation between atrial activation evaluated by the two methods. Total P wave duration and morphology in inferior leads identified three patterns: normal P wave, late‐positive P wave, and late‐negative P wave. Proximal and distal esophageal recording characterized the longitudinal direction of activation of the posterior left atrium. We distinguished three activation patterns: normal activation when the interatrial conduction time is normal and depolarizes in craniocaudal direction, delayed activation when the interatrial conduction time is prolonged and the craniocaudal activation is maintained, and finally reversed activation when the posterior left atrium depolarizes in a reversed caudocranial direction. Four patients showed a normal P wave and also had a normal esophageal activation. Twelve patients showed a prolonged P wave (associated with delayed esophageal activation in 10 patients and reversed activation in 2 patients); 14 patients had a late‐negative P wave (all associated with a reversed esophageal activation). A high correlation existed between each pattern obtained by surface ECG and esophageal recording (P < 0.001) and between surface P wave duration and interatrial conduction time (R2= 0.64, P < 0.001). Much information concerning atrial activation can be obtained by meticulous analysis of the P wave, particularly its terminal part. Multipolar esophageal recording can be used when surface ECG appears unclear. (PACE 2003; 26:1178–1188)
An Adaptive Interval‐Based Algorithm for Withholding ICD Therapy During Sinus Tachycardia
Authors: STADLER ROBERT W. , GUNDERSON BRUCE D. , GILLBERG JEFFREY M.
Published: May 2003

Avoiding inappropriate ICD therapy during supraventricular tachycardia (SVT) while assuring 100% sensitivity for VT/VF remains a challenge. Inappropriate VT/VF therapy during sinus tachycardia (ST) is particularly distressing to the patient because the full sequence of ICD therapies is often delivered. ST or 1:1 atrial tachycardia (AT) with long PR intervals and ST or AT with atrial oversensing of far‐field R waves cause the majority of inappropriate therapy in the Medtronic GEM DR (Model 7271) ICD. The goals of the present effort were to define an adaptive interval‐based algorithm for withholding VT/VF therapy in dual chamber ICDs during ST and to compare performance of the adaptive algorithm with that of the original ST withholding algorithm in the GEM DR. The adaptive algorithm uses a combination of 1:1 atrial to ventricular conduction pattern, changes in RR intervals and changes in intrinsic PR intervals to establish evidence for or against the presence of ST. Performances of the adaptive and original ST withholding algorithms were compared on 3 databases collected by implanted GEM DR devices. The first database included 684 spontaneous VT/VF episodes. The second database included 216 spontaneous SVT episodes that received inappropriate VT/VF therapy. These databases included up to 2,000 atrial or ventricular sensed or paced events preceding the spontaneous tachycardias. The third database included 320 spontaneous ST/AT episodes for which therapy was appropriately withheld by the GEM DR. Performance of the adaptive algorithm on the third database was predicted rather than directly computed because of record length limitations. VT/VF therapy was classified as “withheld” if evidence of ST remained high for one algorithm (i.e., at least 7 more beats to VT/VF detection) at the point of VT/VF detection by the other algorithm. For the 684 true VT/VF episodes, the original algorithm withheld VT/VF therapy in 5 episodes and the adaptive algorithm withheld VT/VF therapy in 3 episodes. The 95% confidence interval for the difference in VT/VF sensitivity between the adaptive and original algorithms was [−0.5 to +1.1%]. Twelve of the 320 ST/AT episodes (3.8%) that were appropriately classified by the original algorithm were predicted to receive inappropriate therapy by the adaptive algorithm. However, relative to the original algorithm, the adaptive algorithm appropriately withheld VT/VF therapy for 76 of 216 true SVT episodes (i.e., incremental specificity of 35.2%). For the specific SVT episodes that were the targets for improvement by the adaptive ST algorithm (ST/AT with long PR intervals and ST/AT with intermittent atrial oversensing of far‐field R waves), the adaptive algorithm reduced inappropriate therapy by 63.2%. (PACE 2003; 26:1189–1201)
Myocardial Perfusion and Adrenergic Innervation in Patients with RBBB and LAFB:
Authors: SIMANTIRAKIS EMMANUEL N. , PRASSOPOULOS VASILIOS K. , MARKETOU MARIA E. , CHRYSOSTOMAKIS STAVROS I. , KOUKOURAKI SOPHIA I. , LEKAKIS JOHN P. , KARKAVITSAS NIKOLAOS S. , VARDAS PANOS E.
Published: May 2003

The aim of this study was to investigate myocardial perfusion and adrenergic innervation in patients with intraventricular conduction disturbances and to detect any changes caused by alteration of the ventricular activation sequence as a result of right ventricular apical pacing. We studied 15 patients with right bundle branch block (RBBB) and left anterior fascicular block (LAFB), while 15 healthy individuals served as controls. All patients underwent planar and single‐photon emission computed tomography (SPECT) myocardial imaging after intravenous infusion of 5mCi 123I‐metaiodobenzylguanidine (123I‐MIBG) and a SPECT thallium201 myocardial perfusion study before and 3 months after pacemaker implantation. The heart to mediastinum ratio was calculated during the 123I‐MIBG study in order to assess the global cardiac sympathetic activity and was significantly smaller in patients than in controls (P < 0.001). Patients with RBBB and LAFB revealed regional adrenergic innervation defects, mostly in the inferior and posterior walls. After a medium‐term pacing period, a redistribution of 123I‐MIBG uptake was detected, with aggravation of adrenergic innervation defects in the apical and posterior walls and amelioration in septal and anterior walls. Five patients showed perfusion defects that remained unchanged after pacing. Two others displayed mild myocardial perfusion defects that did not exist before pacing. In conclusion, patients with RBBB and LAFB reveal global and regional disturbances of myocardial adrenergic innervation, which shows redistribution as a result of the altered propagation of the ventricular electrical activation. To a smaller degree these patients reveal myocardial perfusion disturbances in which pacing has a limited medium‐term effect. (PACE 2003; 26:1202–1207)
Single Versus Dual Chamber Pacing in the Young:
Authors: HORENSTEIN M. SILVANA , KARPAWICH PETER P. , VICTORIA M. , TANTENGCO T.
Published: May 2003

The advantages of atrial synchrony over asynchronous ventricular pacing remain unclear in the young, chronically right ventricular (RV) ‐ paced patient. This is in contrast to the older patient with inherent diastolic dysfunction who has been shown to benefit from atrial synchrony with dual chamber (DDD,R/VDD), over single chamber rate response (VVI,R) ventricular pacing. The goal of this study was to noninvasively assess cardiac function in a group of young, RV‐paced patients before and after establishment of atrial synchrony. Echocardiographic data were retrospectively analyzed from 10 patients with congenital or acquired complete AV block, who were VVI,R paced for 10.2 ± 2 years (mean age at study 19.2 ± 8.9 years), and were subsequently converted to DDD,R/VDD pacing (mean age at study 20.7 ± 9.5 years). Paired t‐test analysis of left ventricular (LV) systolic and diastolic function during VVI,R versus DDD,R/VDD pacing did not result in any short‐term difference in LV short axis fractional area of change or FAC (53%± 7.5% vs 56.8%± 8.7%) or mitral maximal velocity (E) normalized to mitral flow velocity time integral (VTI) (5.2/s ± 1.5 vs 4.4/s ± 1.5). A decrease in mitral flow E/A ratio was observed after short term DDD,R/VDD pacing (2.2 ± 0.5 vs 1.9 ± 0.3). Atrial synchronous dual chamber pacing in young patients with complete AV block does not lead to any appreciable early change in global LV function over single‐site RV pacing. Therefore, early establishment of atrial synchrony in the young asymptomatic VVI,R‐paced patient with normal intrinsic ventricular function may not be warranted. (PACE 2003; 26:1208–1211)
AV Nodal Ablation and Pacemaker Implantation Improves Hemodynamic Function in Atrial Fibrillation
Authors: TAKAHASHI YOSHIHIDE , YOSHITO IESAKA , TAKAHASHI ATSUSHI , HARADA TOMOO , MITSUHASHI TAKESHI , SHIROTA KINYA , KUMAGAI KOICHIRO , NURUKI NORIHITO , SHIRAISHI TAKAYOSHI , NITTA JUNICHI , ITO HIROSHI ,   The ablation and pacing therapy working group
Published: May 2003

In drug refractory and highly symptomatic atrial fibrillation (AF) patients, hemodynamic effects of AV node ablation and pacing therapy (APT) were evaluated. Thirty‐eight patients with drug refractory and symptomatic AF, underwent APT in eight centers in Japan. The outcome of this therapy was assessed in terms of quality‐of‐life, cardiac performance measured by echocardiogram, and plasma ANP and BNP levels before and after APT. Quality‐of‐life assessed by self‐administered semiquantitative questionnaires: WHO QOL 26 (

3.0 ± 0.5

vs

3.4 ± 0.6, P < 0.01

) and the Symptom Checklist: Frequency Scale (

1.6 ± 0.6

vs

0.7 ± 0.7, P < 0.01

) and Severity Scale (

1.3 ± 0.4

vs

0.6 ± 0.6, P < 0.01

), improved significantly 6 months after APT. Ejection fraction (EF) by echocardiogram improved 1 week after APT (

59.0%± 13.3%

vs

63.3%± 11.6%, P = 0.02

). Plasma ANP levels in the group of

ANP > 40 pg/mL

at enrollment significantly decreased 1 month later

(P = 0.03)

, and plasma BNP levels in the group of

BNP > 20 pg/mL

at enrollment significantly decreased 1 month later

(P < 0.01)

. In conclusion, APT has beneficial hemodynamic effects, and plasma BNP levels can predict the most optimal candidates for ablation and pacing therapy. (PACE 2003; 26:1212–1217)
Late Improvement in Ventricular Performance Following Internal Cardioversion for Persistent Atrial Fibrillation:
Authors: BORIANI GIUSEPPE , BIFFI MAURO , RAPEZZI CLAUDIO , FERLITO MARINELLA , BRONZETTI GABRIELE , BACCHI LETIZIA , ZANNOLI ROMANO , BRANZI ANGELO
Published: May 2003

The aim of the study was to evaluate the time course of atrial and ventricular function improvement following internal atrial cardioversion in patients with structural heart disease. Twenty‐nine patients with chronic persistent atrial fibrillation (AF) and underlying structural heart disease were followed by serial echocardiograms performed at 1 and 6 hours, 1 day, 1, 2, and 3 weeks, and 1, 2, 3, and 6 months after successful cardioversion. Sinus rhythm was maintained at 6 months in 24 patients. Following cardioversion the time course of left atrial mechanical function (peak A wave, percent A wave filling) differed from that of left ventricular ejection fraction: peak A wave values (cm/s) increased significantly at 1 week (

51 ± 23

vs

35 ± 15

at 1 hour,

P < 0.05

), percent A wave filling (%) increased significantly at 2 weeks (

34 ± 12

vs

22 ± 9

at 1 hour,

P < 0.05

), whereas left ventricular ejection fraction (%) increased later (at 1 month

60 ± 14

vs

55 ± 14

at baseline,

P < 0.05

and at 2 months

60 ± 14

vs

56 ± 14

at 1 hour,

P < 0.05

). In conclusion, restoration of sinus rhythm results in an improvement in left ventricular ejection fraction during follow‐up, even in patients with structural heart disease without fast ventricular rates at baseline. The dissociation between the time course of atrial and ventricular function improvement suggests that the latter was partly due to regression of a concealed form of cardiomyopathy and/or of a ventricular dysfunction due to chronic AF. (PACE 2003; 26:1218–1226)
High Incidence of Thrombus Formation Without Impedance Rise During Radiofrequency Ablation Using Electrode Temperature Control
Authors: MATSUDAIRA KAGARI , NAKAGAWA HIROSHI , WITTKAMPF FRED H.M. , YAMANASHI WILLIAM S. , IMAI SHINOBU , PITHA JAN V. , LAZZARA RALPH , JACKMAN WARREN M.
Published: May 2003

The authors hypothesized that during RF ablation, the electrode to tissue interface temperature may significantly exceed electrode temperature in the presence of cooling blood flow and produce thrombus. In 12 anesthetized dogs, the skin over the thigh muscle was incised and raised to form a cradle that was superfused with heparinized canine blood
(ACT > 350 s)
at 37°C. A 7 Fr, 4‐mm or 8‐mm ablation electrode containing a thermocouple was held perpendicular to the thigh muscle at 10‐g contact weight. Interface temperature was measured at opposite sides of the electrode using tiny optical probes. RF applications

(n = 157)

were delivered at an electrode temperature of 45°C, 55°C, 65°C, and 75°C for 60 seconds, with or without pulsatile blood flow (150 mL/min). Without blood flow, the interface temperature was similar to the electrode temperature. With blood flow, the interface temperature (side opposite blood flow) was up to 36°C and 57°C higher than the electrode temperature using the 4‐ and 8‐mm electrodes, respectively. After each RF, the cradle was emptied and the electrode and interface were examined. Thrombus developed without impedance rise at an interface temperature as low as 73°C without blood flow and 80°C with blood flow (11/16 RFs at 65°C electrode temperature using 4 mm and 13/13 RFs at an electrode temperature of 55°C using an 8‐mm electrode with blood flow). With blood flow, interface temperature markedly exceeded the electrode temperature and the difference was greater with an 8‐mm electrode (due to greater electrode cooling). In the presence of blood flow, thrombus occurred without an impedance rise at an electrode temperature as low as 65°C with a 4‐mm electrode and 55°C with an 8‐mm electrode. (PACE 2003; 26:1227–1237)
Relation of Age and Sex to Atrial Electrophysiological Properties in Patients with No History of Atrial Fibrillation
Authors: SAKABE KOICHI , FUKUDA NOBUO , SOEKI TAKESHI , SHINOHARA HISANORI , TAMURA YOSHIYUKI , WAKATSUKI TETSUZO , NISHIKADO AKIYOSHI , OKI TAKASHI
Published: May 2003

Although atrial fibrillation is a common arrhythmia, especially in elderly men, little is known about age related changes in atrial electrophysiological properties or gender differences. The aim of this study was to analyze the effects of aging on vulnerability to atrial fibrillation and assessed gender differences in those age related changes. An electrophysiological study was performed on 73 patients with no history of atrial fibrillation, structural heart disease, or conditions with potential effects on cardiac hemodynamic or electrophysiological function, including 25 women (mean age 49 ± 18 years; range 12–84 years). The following atrial excitability parameters were assessed: spontaneous or paced (A1) and extrastimulated (A2) atrial electrogram widths, percent maximum atrial fragmentation

(A2/A1 × 100)

, effective refractory period, wavelength index (effective refractory period/A2), and inducibility of atrial fibrillation. There were no significant differences in percent maximum atrial fragmentation (

143 ± 28

vs

142 ± 35%

), effective refractory period (

241 ± 39

vs

238 ± 50 ms

), wavelength index (

2.9 ± 0.8

vs

3.1 ± 0.9

), induction of atrial fibrillation (10 [21%] vs 7 [28%]), or age (

50 ± 17

vs 49 ± 20 years) between men and women. Age was not statistically different between those patients with and without induction of atrial fibrillation in men (

48 ± 14

vs

50 ± 18 years

) and women (

48 ± 18

vs

49 ± 21 years

). Percent maximum atrial fragmentation and effective refractory period were directly correlated with age in men (

r = 0.35, P = 0.01; r = 0.46, P < 0.001

, respectively) and women (

r = 0.42, P = 0.04; r = 0.45, P = 0.02

, respectively), though wavelength index did not correlate with age in men (r =−0.04) or women (r =−0.04) with no history of atrial fibrillation. Considering these findings, the authors conclude that the mechanism triggering atrial fibrillation may be different between older and younger patients with atrial fibrillation, because younger patients who have no marked substrate for atrial fibrillation may need many trigger beats to induce atrial fibrillation. (PACE 2003; 26:1238–1244)
Utility and Safety of Prolonged Temporary Transvenous Pacing Using an Active‐Fixation Lead:
Authors: DE COCK C.C. , VAN CAMPEN C.M.C. , IN'T VELD J.A. , VISSER C.A.
Published: May 2003

Transvenous temporary pacing is associated with a substantial dislocation rate reported to range from 10 to 37%. The aim of the study was to assess the safety and utility of a recently introduced 3.5 Fr temporary pacing lead using active fixation in a consecutive series of 36 patients with prolonged (≥48 hours) transvenous temporary pacing (validation group). A group of 36 patients with prolonged transvenous pacing managed with a passive‐fixation lead just prior to the introduction of the active‐fixation lead served as a control group (reference group). Pacing related adverse events included dislocation, inappropriate pacing (i.e., two‐fold or greater increase of initial pacing threshold), local infection, and thrombosis. There were no significant differences in patient characteristics or duration of pacing (

5.84 ± 2.4 days

in the reference group vs

5.94 ± 2.6 days

in the validation group). Acute pacing threshold was significantly higher in the validation group as compared to the reference group (

1.38 ± 0.67 V

vs.

0.7 ± 0.21 V, P < 0.01

). The dislocation rate was significantly lower in the validation group as compared to the reference group (5.5 vs 33.3%,

P < 0.001

). There were 11 (31%) pacing related adverse events in the validation group versus 21 (58%) in the reference group

(P < 0.01)

. The vast majority of patients in the validation group (75%) had ambulatory temporary pacing. Thus, transvenous temporary pacing using active fixation is safe and is associated with a low dislocation rate and a reduction in pacing related adverse events. (PACE 2003; 26:1245–1248)
Dose‐Response Relationship for Successful Internal Atrial Defibrillation
Authors: TSE HUNG‐FAT , LAU CHU‐PAK , AYERS GREGORY M.
Published: May 2003

The dose‐response relationship for successful defibrillation has been determined in man for the ventricle but not for the atrium. The purpose of this study was to determine the dose‐response relationship for internal atrial defibrillation in humans. Seventy‐seven consecutive patients underwent internal atrial defibrillation for acute (n = 14) or chronic AF (n = 63). Shocks were delivered in 40‐V increments between electrodes positioned in the coronary sinus and the right atrium until successful conversion or a maximum of 400 V was reached. The shock strength versus success of shock data were subjected to a Kaplan‐Meier survival analysis combined with a nonparametric probability analysis to arrive at the dose‐response relationship. Using this relationship, comparisons were made between acute and chronic AF and clinical relevant conversion percentages (20, 50, 80 and 95%) were estimated and were compared with the conventional mean threshold. There were significant dose‐response relationships in both patients groups (P < 0.05). The Kaplan‐Meier analysis comparing patients with chronic and acute AF showed significant differences in their dose‐response relationships (P < 0.001). The estimated shock intensity for 95% conversion in patients with acute and chronic AF was 279 V (2.9 J) and 433 V (6.6 J), respectively (P < 0.001). The conventional mean defibrillation threshold in patients with acute (192 ± 15 V. 1.4 ± 0.2 J) and chronic AF (343 ± 8 V, 4.4 ± 0.2 J) predicted the 60% and 45% chance of successful conversion, respectively. In conclusion, this study demonstrates that single shock conversion data can be used to determine a dose‐response relationship, which can be used to estimate the shock intensity required for specific successful atrial defibrillation efficacy and to compare different clinical factors that affect defibrillation efficacy. (PACE 2003; 26:1249–1253)
Effects of Sulfonylurea Hypoglycemic Agents and Adenosine Triphosphate Dependent Potassium Channel Antagonists on Ventricular Arrhythmias in Patients with Decompensated Heart Failure
Authors: ARONSON DORON , MITTLEMAN MURRAY A. , BURGER ANDREW J.
Published: May 2003

Hypoglycemic sulfonylureas block cardiac ATP‐sensitive potassium channels (KATP). The opening of these channels in cardiomyocytes can induce arrhythmias. In animal studies, sulfonylureas exert an antiarrhythmic effect on the ischemic myocardium, but data on human arrhythmic events are lacking. The study population included 207 patients (age 61 ± 14 years) admitted for decompensated CHF. The severity of ventricular arrhythmias was assessed by 24‐hour Holter monitoring. None of the patients were on parenteral vasoactive therapy or antiarrhythmics during Holter recording. Diabetic patients comprised 48% of the study population, and 34% of diabetic patients were prescribed sulfonylureas. The mean hourly ventricular pairs (

3.6 ± 0.5

vs

1.8 ± 0.3, P = 0.03

), the mean hourly repetitive ventricular beats (

5.7 ± 1.0

vs

2.6 ± 0.1, P = 0.03

), and the frequency of ventricular tachycardia episodes per 24 hours (

4.7 ± 0.8

vs

2.2 ± 0.4, P = 0.03

) were significantly lower in patients with diabetes who were receiving sulfonylureas compared with nondiabetics. No significant difference occurred between patients with diabetes who were not receiving sulfonylureas and nondiabetic patients. Multivariate regression revealed a negative independent relationship between sulfonylurea therapy and hourly ventricular pairs

(P = 0.03),

the mean hourly repetitive ventricular beats

(P = 0.03),

and ventricular tachycardia episodes

(P = 0.04)
. In a multiple logistic regression, sulfonylurea therapy was a negative predictor of repetitive ventricular beats (P = 0.01,adjusted OR, 0.31; 95% CI, 0.12–0.78). Concomitant sulfonylurea therapy may reduce the occurrence of complex ventricular ectopy in the setting of severe CHF. These results suggest that cardiac KATP channel activation may be involved in the genesis of ventricular arrhythmias in CHF. (PACE 2003; 26:1254–1261)
Significance of the Morphological Patterns of Electrograms Recorded During Ventricular Fibrillation:
Authors: CHORRO FRANCISCO J. , FERRERO ANGEL , CANOVES JOAQUÍN , MAINAR LUIS , PORRES JUAN C. , NAVARRO ALEJANDRO , SANCHIS JUAN , MILLET JOSÉ , BODÍ VICENTE , LÓPEZ‐MERINO VICENTE , SUCH LUIS
Published: May 2003

Mapping techniques are used to study the significance of the morphological patterns of the electrograms (EGMs) obtained during VF in an experimental model. In 24 isolated rabbit heart preparations recordings were made of activation during VF using a multiple electrode (121 unipolar electrodes) positioned on the lateral wall of the left ventricle. Three types of activation maps were selected: (A) with functional block of an activation front; (B) with epicardial breakthrough; and (C) with a single broad wavefront without block lines. The EGMs were classified as negative (Q), positive‐negative with a predominance of the negative (rS) or positive wave (Rs), and positive (R). In 60 type A maps the morphology in the zone limiting the block line corresponded to an R wave in 55 (92%) cases and to Rs in 5 (8%) cases. In 67 type B maps, the EGM in the earliest activation zone most often showed Q wave morphology (48 [72%] cases), followed by rS (18 [27%] cases), and Rs morphology (1 [1%] case); in no case was R wave morphology seen. Finally, in 78 type C maps the morphology corresponded to a Q wave in 15 (19%) cases, rS in 38 (49%), Rs in 24 (31%), and R in a 1 (1%) case. The differences between the three types of maps were significant (P < 0.0001). Q wave EGM sensitivity for indicating the existence of an epicardial breakthrough pattern was 72%, with a specificity of 89%, and positive and negative predictive values of 76% and 87%, respectively. R wave EGM sensitivity for indicating the existence of conduction block was 92%, with a specificity of 99%, and positive and negative predictive values of 98% and 97%, respectively. R wave morphology is highly sensitive and specific for indicating conduction block. EGM recordings with initial positivity predominance are infrequent in the earliest activation zones of epicardial breakthrough during VF. The recording of the EGM with Q wave morphology indicates centrifugal activation from the explored zone. (PACE 2003; 26:1262–1269)
Pacemaker Mode Selection:
Authors: MONTANEZ ALICIA , HENNEKENS CHARLES H. , ZEBEDE JOSEPH , LAMAS GERVASIO A.
Published: May 2003

The evidence base for pacing, specifically with regards to outcome‐based randomized trials, is only beginning to emerge. At present, the guidelines for pacing in sinus node dysfunction (SND), atrioventricular block (AVB), and vasovagal syncope are largely based on observational, not randomized studies. The findings from observational studies that physiological pacing was associated with reduced mortality, fewer strokes, less heart failure, and less AF when compared with ventricular pacing, were not uniformly supported by the early randomized trials of a relatively small sample size. Thus, it has become increasingly clear that large scale randomized trials are necessary to measure reliably the benefit, if any, of progressively more expensive and complex pacemakers. To provide reliable answers to these important questions, three large multicenter randomized trials in Canada, the United Kingdom, and the United States have been designed and conducted. The present review analyzed the results of completed randomized trials on pacemaker mode selection. To date, >6,000 patients requiring permanent pacing to prevent bradycardia have been randomized; among these, dual chamber pacing did not prevent stroke or improve survival when compared with ventricular pacing. However, dual chamber pacing led to a moderate reduction of incident and chronic AF, reduced symptoms of heart failure in patients with SND, prevented pacemaker syndrome, and modestly improved quality‐of‐life. Further, a 5–10% reduction in mortality by atrial‐based pacing cannot be excluded based on the results of the analyzed trials. The availability of data from ongoing randomized trials and their meta analysis should complete the totality of evidence during the next several years. (PACE 2003; 26:1270–1282)
Radiofrequency Catheter Ablation of Junctional Ectopic Tachycardia with Preservation of Atrioventricular Conduction
Authors: SIMMERS TIMOTHY A. , SREERAM NARAYANSWAMI , WITTKAMPF FRED H.M. , DERKSEN RICHARD
Published: May 2003

Junctional ectopic tachycardia is a relatively rare disorder, frequently refractory to drug therapy, and with a poor prognosis in childhood. This report describes a successful radiofrequency catheter ablation of the focus of this arrhythmia in a 9‐year‐old girl with preservation of normal atrioventricular conduction, using precise catheter navigation with the LocaLisa system and carefully titrated RF delivery. (PACE 2003; 26:1284–1288)
Electrocardiographic Changes Due to Pyridoxine Deficiency
Authors: MALMIERCA EDUARDO , POLO JORGE , CASTRO JORGE R.
Published: May 2003

A young woman presented with marked alterations in the ECG without cardiological symptoms or evidence of structural heart disease after further evaluation. There was evidence of vitamin deficiency and the ECG normalized after 10 days of treatment with vitamins. Similar alterations have been described in several experimental studies with rats, but this is the first case reported in humans. (PACE 2003; 26:1289–1291)
Electrical Interference from an Abdominal Muscle Stimulator Unit on an Implantable Cardioverter Defibrillator:
Authors: WAYAR LUIS , MONT LLUIS , SILVA ROSE M.F.L. , ALVARENGA NELSON , FOSCH XAVI , CASTRO JESÚS , BRUGADA JOSEP
Published: May 2003

Two consecutive cases are presented of patients with ICDs in whom the use of commercial units for muscle stimulation for abdominal training caused interference with the device, mimicked cardiac signals, and resulted in inappropriate treatment shock delivery. (PACE 2003; 26:1292–1293)
Implantation of a Biventricular Pacing System in a Patient with a Coronary Sinus Not Communicating with the Right Atrium
Authors: VAN GELDER BERRY M. , ELDERS JAN , BRACKE FRANK A. , MEIJER ALBERT
Published: May 2003

Intubation of the coronary sinus failed during implantation of a biventricular pacing system. An angiogram of the left coronary artery showed in the venous phase a coronary sinus not communicating with the right atrium. The coronary sinus was draining into a persistent left superior vena cava communicating with the left subclavian vein. The coronary sinus lead was successfully implanted through the persistent left superior vena cava, whereas the atrial and ventricular leads were implanted through the right superior vena cava in a conventional way. (PACE 2003; 26:1294–1296)