bluuebunny/crossref_metadata_2025 huggingface dataset:
Leading the development of nursing within a Nursing Development Unit: The perspectives of leadership by the team leader and a professor of nursing
Authors: Graham Iain
Published: July 2003

Leadership within nursing is receiving unprecedented focus and development. This reflective narrative explores the nature of leadership, termed scholarly leadership, by an academic and a clinical leader of a Nursing Development Unit. The narrative explores the characteristics of such leadership and highlights how it empowered a nursing team to further reach its potential. Two areas, patient‐centered care and the characteristics of practice, are focused upon to highlight the leadership style that the clinical leader adopted. The paper concludes by suggesting what structural and systems changes need to be put in place in order to bring about change.
Evolution of surgery in the treatment of breast cancer
Authors: Cheung Polly Suk‐Yee
Published: July 2003

Surgery is the most important element in achieving cure for breast cancer. Its evolution in the last century was linked to a better understanding of the disease and the development of multimodality treatment. New techniques involved less mutilation, less morbidity and were more aesthetically acceptable, without jeopardizing the outcome. Modern breast cancer surgery requires operating using images and integrating plastic surgery techniques.
Factors associated with long hospital stay in geriatric wards in Japan
Authors: Umegaki Hiroyuki , Ando Fujiko , Shimokata Hiroshi , Yamamoto Sayaka , Nakamura Akira , Endo Hidetoshi , Kuzuya Masafumi , Iguchi Akihisa
Published: July 2003

Background:  To reduce the length of stay (LOS) in hospital, the factors associated with extended LOS have to be identified.

Methods:   A comprehensive geriatric assessment (CGA) of patients in a geriatric ward was carried out to identify the factors associated with LOS of more than 28 days.

Results:   Of 193 patients (> 65 years old) who had been admitted to the geriatric ward of Nagoya University Hospital from home, 118 patients had complete CGA data sets. The CGA items were studied within 1 week of admission and analysis was performed by Chi‐squared followed by multilogistic analysis. Chi‐squared analysis demonstrated that many of the basic activities of daily living (BADL) and instrumental ADL (IADL) had a significant association with longer LOS, but the contribution of psychological factors, assessed by mini‐mental state examination and Geriatric Depression Scale‐15, was relatively small. Multilogistic analysis showed that dependence on dressing assistance and medication assistance significantly increased the chance of having a LOS longer than 28 days.

Conclusion:   Intervention to improve the ability to dress and take medication independently may reduce LOS.
Successful use of minocycline hydrochloride sclerotherapy to treat a functioning parathyroid cyst in a 76‐year‐old woman
Authors: Higashimoto Yuji , Masahiro Ohata , Takuya Iwata , Tadashi Ishiguchi , Hiroya Nakata , Hiroaki Satou , Kouji Itoh , Hisashi Fujimoto , Hidekazu Itoh
Published: July 2003

Parathyroid cysts (PC) are uncommon: only 230 cases have been reported. They can be functional or non‐functional. The standard treatment consists of percutaneous aspiration of the cyst and surgical excision for recurrent lesions. An unusual case of a functioning PC was successfully treated with sclerotherapy using minocycline hydrochloride in a 76‐year‐old woman. Following this procedure, the patient has remained asymptomatic with no recurrence. This is the first report of the effective use of minocycline hydrochloride in sclerotherapy for a PC.
Aged onset of amyloidosis caused by transthyretin gene mutations
Authors: Nakazato Masamitsu , Matsukura Shigeru
Published: July 2003

Background:  The authors have established that missense mutations of the transthyretin gene cause middle age onset of familial systemic amyloidosis. The purpose of the present study was to investigate molecular abnormalities of the serum protein, transthyretin in patients with aged onset of cardiac amyloidosis or amyloidotic polyneuropathy in whom there was no positive family history of amyloidosis.

Methods:  DNA and isolated amyloid fibril proteins were extracted from biopsy or postmortem tissue samples taken from five patients with cardiac amyloidosis and 15 patients with amyloidotic polyneuropathy, in whom histological diagnosis of amyloidosis had been established by immunostaining for transthyretin.

Results:  DNA analysis of the transthyretin gene and protein sequencing of the amyloid fibrils revealed that three of the five patients with cardiac amyloidosis were associated with transthyretin Met 30, and the remaining two patients were associated with transthyretin Ile 50. Of the 15 patients with amyloidotic polyneuropathy, 12 were associated with transthyretin Met 30, two with transthyretin Ile 50, and one with transthyretin Ser 109.

Conclusion:  The clinical findings, results of DNA sequencing and structural analysis of amyloid protein are presented here for six representative subjects. Molecular abnormalities of transthyretin are the cause of some patients with aged onset of amyloidosis without a positive family history. Even when transthyretin‐type amyloid was first diagnosed at autopsy, it was possible to identify transthyretin gene mutations by the use of small pieces of tissue samples.
Functional characterization of a neuropeptide F‐like receptor from Drosophila melanogaster
Authors: Feng Guoping , Reale Vincenzina , Chatwin Heather , Kennedy Karen , Venard Renée , Ericsson Christer , Yu Kweon , Evans Peter D. , Hall Linda M.
Published: July 2003

A cDNA clone encoding a seven‐transmembrane domain, G‐protein‐coupled receptor (NPFR76F, also called GPCR60), has been isolated from Drosophila melanogaster. Deletion mapping showed that the gene encoding this receptor is located on the left arm of the third chromosome at position 76F. Northern blotting and whole mount in situ hybridization have shown that this receptor is expressed in a limited number of neurons in the central and peripheral nervous systems of embryos and adults. Analysis of the deduced amino acid sequence suggests that this receptor is related to vertebrate neuropeptide Y receptors. This Drosophila receptor shows 62–66% similarity and 32–34% identity to type 2 neuropeptide Y receptors cloned from a variety of vertebrate sources. Coexpression in Xenopus oocytes of NPFR76F with the promiscuous G‐protein Gα16 showed that this receptor is activated by the vertebrate neuropeptide Y family to produce inward currents due to the activation of an endogenous oocyte calcium‐dependent chloride current. Maximum receptor activation was achieved with short, putative Drosophila neuropeptide F peptides (Drm‐sNPF‐1, 2 and 2s). Neuropeptide F‐like peptides in Drosophila have been implicated in a signalling system that modulates food response and social behaviour. The identification of this neuropeptide F‐like receptor and its endogenous ligand by reverse pharmacology will facilitate genetic and behavioural studies of neuropeptide functions in Drosophila.
Anatomical organization of the telencephalic connections of the parafascicular nucleus in adult and developing rats
Authors: Vercelli Alessandro , Marini Gabriella , Tredici Giovanni
Published: July 2003

The parafascicular nucleus (PFN) of the rat, homologous to the human centre médian, is an intralaminar nucleus of the thalamus, classically considered as part of the ascending activating system. We have previously demonstrated that it is also connected to several subcortical nuclei. To obtain a more detailed picture of the connectivity of the PFN, the organization and the topography of the reciprocal parafascicular–telencephalic relationships were studied in both adult and developing rats, using anterograde and retrograde neuronal tracers. In the adult rat, the ascending parafascicular projections were densest to the striatum, dense to the frontal and least dense to cingulate cortex, and were strictly ipsilateral. They displayed a loose topography, with the more medial parafascicular neurons projecting to the medial frontal and cingulate cortex and medial striatum, and the more lateral neurons projecting to the lateral frontal cortex and lateral striatum. All these connections were already present at embryonic day 19. Parafascicular neurons projecting to the telencephalon in adult rats were mostly of the multipolar type, with a few bipolar neurons. In neonatal rats they showed a bipolar morphology at birth; they became mostly multipolar later on, with an increasing complexity of the dendritic arbor up to postnatal day 10. Neurons in the frontal cortex retrogradely labelled from the PFN were more numerous perinatally, and decreased as early as postnatal day 5. The telencephalic connections of the PFN were found to be more discrete and restricted than previously thought, thus suggesting a more specific functional role for the nucleus than cortical recruitment.
Substrates and routes of migration of early generated neurons in the developing rat thalamus
Authors: Ortino Barbara , Inverardi Francesca , Morante‐Oria Javier , Fairén Alfonso , Frassoni Carolina
Published: July 2003

We investigated the substrates supporting neuronal migration, and its routes, during early thalamic development in the rat. Neurons and axonal and glial fibres were identified in embryos with single and double immunohistochemistry; dynamic data were obtained with cell tracers in short‐term organotypic cultured slices. The earliest thalamic neurons, originating from the ventricular neuroepithelium between embryonic days 13 and 15, include those of the reticular thalamic nucleus. At this developmental stage, calretinin, calbindin or γ‐aminobutyric acid immunostaining revealed both radially and nonradially orientated neurons in the region of reticular thalamic migration, between the dorsal and ventral thalamic primordia. In cultured slices, injections of fluorescent dyes in the neuroepithelium labelled neurons in a migratory stream along radial glia in the same zone. Some labelled fusiform cells departed from this radial trajectory along orthogonal routes within the dorsal thalamus. Confocal microscopy revealed nonradially orientated neurons in close apposition with a fibre system parallel to the lateral thalamic surface. These fibres expressed axonal markers, including the intermediate filament protein α‐internexin and a polysialylated form of neuronal cell adhesion molecule. Active migration of nonradially orientated neurons along neuronal substrates was confirmed in living cultured slices. In addition, in vitro and ex vivo experiments revealed neurons migrating tangentially in association with glial fibres. These results provide novel evidence that: (i) early generated thalamic neurons follow nonradial routes in addition to glia‐linked radial migration; and (ii), nonradially migrating thalamic neurons move along both glial and axonal substrates, which could represent a distinctive feature of thalamic development.
Viral vector‐mediated gene transfer of the vole V1a vasopressin receptor in the rat septum: improved social discrimination and active social behaviour
Authors: Landgraf Rainer , Frank Elisabeth , Aldag John M. , Neumann Inga D. , Sharer Catherine A. , Ren Xianghui , Terwilliger Ernest F. , Niwa Masanobu , Wigger Alexandra , Young Larry J.
Published: July 2003

This study explores the effects of enhancing vasopressin V1a receptor expression in the septum using viral vector‐mediated gene transfer on social discrimination and social interactions. Bilateral infusion of an adeno‐associated viral vector containing the prairie vole V1a receptor gene (V1aR‐AAV) regulated by a neuron‐specific enolase promoter resulted in a stable increase in V1a receptor binding density in the rat septum without affecting oxytocin receptor density. Control animals were infused with a vector expressing the lacZ gene. In a social discrimination paradigm, only V1aR‐AAV‐treated animals succeeded in discriminating a previously encountered from a novel juvenile after an interexposure interval (IEI) of more than 2 h, demonstrating the functional incorporation of the vole V1a receptor in the rat septal circuits underlying short‐term memory processes. Microdialysis administration of synthetic vasopressin during the first juvenile exposure, used to mimic intraseptal release patterns of the neuropeptide, produced similar prolongations in recognition (up to an IEI of 24 h) in both V1aR‐AAV and control animals. Septal microdialysis administration of a selective V1a, but not oxytocin, receptor antagonist in both groups prevented discrimination even after an IEI of as short as 0.5 h, confirming the specificity of the vole V1a receptor involvement in social discrimination abilities. In addition, active social interactions were found to be increased among V1aR‐AAV rats compared to controls. Viral vector‐mediated gene transfer provides a valuable tool for studies on the role of localized gene expression on behavioural parameters.
Xenopus embryonic spinal neurons recorded in situ with patch‐clamp electrodes – conditional oscillators after all?
Authors: Aiken Simon P. , Kuenzi Frederick M. , Dale Nicholas
Published: July 2003

The central pattern generator for swimming Xenopus embryo is organized as two half‐centres linked by reciprocal inhibition. Microelectrode recordings suggest that Xenopus neurons are poorly excitable, necessitating a key role for postinhibitory rebound in the operation of the central pattern generator. However the Xenopus central pattern generator seems unusual in that the component neurons apparently have no intrinsic or conditional rhythmogenic properties. We have re‐examined the firing properties of Xenopus embryo spinal neurons by making patch‐clamp recordings in situ from intact spinal cord. Recordings made from 99 neurons were divided into three groups. Central pattern generator neurons overwhelmingly (44/51) fired trains of action potentials in response to current injection. Just over half of the sensory interneurons (13/22) also fired trains of action potentials. Neurons that received no synaptic inputs during swimming mostly fired just one or two action potentials (22/26). Thirty‐four neurons were identified morphologically. Commissural (8/12) and descending (6/6) interneurons, key components of the spinal central pattern generator, fired repetitive trains of action potentials during current injection. Neurons that were not part of the central pattern generator did not demonstrate this preponderance for repetitive firing. Analysis of the interspike intervals during current injection revealed that the majority of central pattern generators, descending and commissural interneurons, could readily fire at frequencies up to twice that of swimming. We suggest that Xenopus neurons can be considered as conditional oscillators: in the presence of unpatterned excitation they exhibit an ability to fire rhythmically. This property makes the Xenopus embryonic central pattern generator more similar to other model central pattern generators than has hitherto been appreciated.
Assessment of the Chronotropic Response at the Anaerobic Threshold: An Objective Measure of Chronotropic Function
Authors: MEINE MATHIAS , ACHTELIK MICHAEL , HEXAMER MARTIN , KLOPPE AXEL , WERNER JÜRGEN , TRAPPE HANS‐JOACHIM
Published: July 2003

MEINE, M., et al.: Assessment of the Chronotropic Response at the Anaerobic Threshold: An Objective Measure of Chronotropic Function. The evaluation of the heart rate response to exercise is important for the diagnosis of chronotropic incompetence and the assessment of a rate responsive algorithm of sensorcontrolled pacemakers. The aim of the present study was to examine a classification of the chronotropic response at an individually moderate exercise level. Sixteen pacemaker patients (patient group, age 62.9 ± 7.6 years) with sick sinus syndrome and 15 age‐matched healthy subjects (control group, age 57.6 ± 9.4 years) underwent a maximum cardiopulmonary exercise test on a treadmill after a protocol with individually selected incremental steps. To analyze the patients' intrinsic heart rate response, the rate responsive mode of the pacemaker was switched off. Chronotropic incompetence was diagnosed in eight patients whose maximal heart rate was < 80% of the age‐predicted heart rate. The heart rate at the anaerobic threshold was significantly lower in the chronotropically incompetent subgroup than in the chronotropically competent patients and the healthy subjects (85.9 ± 6.6 beats/min vs 100.3 ± 9.9 beats/min and 112.9 ± 11.7 beats/min, respectively). The chronotropic slope of the heart rate reserve as a function of the metabolic reserve was significantly higher in the control group than in the patient groups with either mild or severe chronotropic incompetence (0.94 ± 0.17 vs 0.64 ± 0.08 and 0.43 ± 0.14, respectively). Furthermore, the chronotropically incompetent response could be divided into a linear type with and without a threshold, an exponential, and a logarithmic type. The anaerobic threshold was an objectively detectable breakpoint at an individually moderate exercise level that could be used for characterization of chronotropic function. At the anaerobic threshold, a physiological heart rate response was about 220 ‐ age – 50 beats/min. A deviation of more than 10 beats/min below this physiological value characterized chronotropic incompetence.
Influence of Autothreshold Sensing and Sinus Rate on Mode Switching Algorithm Behavior
Authors: WOOD MARK A. , ELLENBOGEN KENNETH A. , DINSMOOR DAVID , HESS MIKE , MARKOWITZ TOBY
Published: July 2003

WOOD, M.A., et al. Influence of Autothreshold Sensing and Sinus Rate on Mode Switching Algorithm Behavior. Mode switching is beneficial to pacemaker patients with paroxysmal atrial tachyarrhythmias. However, the optimal mode switching algorithm is still in evolution. Mode switching algorithms and atrial sensing circuitry can influence mode switching behavior. This study compared the mode switching behavior of four Medtronic, Inc. implantable devices: Thera DR model 7960 pacemaker, Kappa 700 model KDR701 pacemaker, Gem DR model 7271 dual chamber pacing defibrillator, and Jewel AF model 7250 dual chamber pacemaker atrial and ventricular defibrillator. The Thera and Gem DR use the same mean atrial rate mode switch algorithm. The Kappa and Jewel AF use four of seven short atrial intervals and an atrial fibrillation evidence counter algorithm, respectively. The Thera and Kappa devices use fixed gain sensing and the Gem DR and Jewel AF use autothreshold atrial sensing. Digitally recorded atrial electrograms from 52 episodes of human atrial fibrillation were fed into each device with differing simulated sinus rates before and after the atrial fibrillation. The percent of appropriate mode switching was highest for the Kappa 700 (94%) and lowest for the Thera (85%) (P = 0.046). The time to mode switching was significantly longer for the Thera and Gem DR compared to the Kappa 700 or Jewel AF (all P < 0.05). The time to mode switching was shorter for the Gem DR (9.0 ± 1.6 s) using autothreshold atrial sensing than for the fixed gain Thera (11.1 ± 2.1 s, P < 0.05). The mean atrial electrogram amplitude and cycle length were not correlated with the time to mode switching for any device. Faster sinus rates shortened the time to mode switching and prolonged the time to resynchronization in the two devices using the mean atrial interval algorithm. In conclusion, (1) mode switching function among these devices is influenced by algorithms and sensing circuitry, (2) the time to mode switching among these devices is influenced by the algorithm and use of autothreshold atrial sensing, and (3) the sinus rate before and after episodes of atrial fibrillation greatly influences the times to mode switching and resynchronization in devices using the mean atrial interval algorithm.
Electroanatomic Mapping to Identify Breakthrough Sites in Recurrent Typical Human Flutter
Authors: SRA JASBIR , BHATIA ATUL , DHALA ANWER , BLANCK ZALMEN , RATHOD SHARAD , BOVEJA BIRENDER , DESHPANDE SANJAY , COOLEY RYAN , AKHTAR MASOOD
Published: July 2003

SRA, J., et al.: Electroanatomic Mapping to Identify Breakthrough Sites in Recurrent Typical Human Flutter. The accuracy of conventional techniques in localizing previous radiofrequency (RF) ablation sites and thus breakthrough sites of recurrent atrial flutter is somewhat limited. We investigated the role of electroanatomic mapping for identifying breakthrough sites or “gaps” at the tricuspid annulus and inferior vena cava (IVC)/eustachian ridge isthmus to help RF ablation in patients with recurrent typical flutter. Twelve patients (8 men, 4 women, age 63 ± 10 years) with recurrent typical atrial flutter were included in the study. An electroanatomic mapping system (CARTO) was used to create a voltage map and activation and propagation patterns in the right atrium. Detailed voltage, activation, and propagation mapping of the tricuspid annulus and IVC/eustachian ridge isthmus allowed precise identification of gaps in all 12 patients at the tricuspid annulus (eight sites), IVC ridges (two sites), mid‐isthmus region (one site), and tricuspid annulus and IVC ridges (one site). Radiofrequency energy directed at these sites eliminated atrial flutter in all 12 patients, confirmed by noninducibility of atrial flutter and demonstration of conduction block during atrial pacing on either side of the lesion lines. During a mean follow‐up of 14.8 ± 3.5 months (range 8–19 months), paroxysmal atrial flutter recurred in only one patient and was subsequently treated with amiodarone, although this had been ineffective prior to ablation. Electroanatomic mapping can precisely identify gaps in the lesion line responsible for breakthrough of recurrent typical atrial flutter at the tricuspid annulus and at the IVC/eustachian ridge isthmus. These sites can be targeted with RF ablation with a high degree of success.
Differentiating the Ligament of Marshall from the Pulmonary Vein Musculature Potentials in Patients with Paroxysmal Atrial Fibrillation: Electrophysiological Characteristics and Results of Radiofrequency Ablation
Authors: TAI CHING‐TAI , HSIEH MING‐HSIUNG , TSAI CHIN‐FENG , LIN YUNG‐KUO , YU WEN‐CHUNG , LEE SHIH‐HUANG , DING YU‐AN , CHANG MAU‐SONG , CHEN SHIN‐ANN
Published: July 2003

TAI, C.‐T., et al.: Differentiating the Ligament of Marshall from the Pulmonary Vein Musculature Potentials in Patients with Paroxysmal Atrial Fibrillation: Electrophysiological Characteristics and Results of Radiofrequency Ablation. It was reported that paroxysmal atrial fibrillation (PAF) can be initiated by ectopic atrial beats originating from the pulmonary vein (PV) or left atrial tract (LAT) within the ligament of Marshall (LOM). The aim of this study was to differentiate the LAT from the PV potentials, and to investigate the results of radiofrequency ablation guided by these potentials. Ten patients (age 60 ± 12 years) with PAF who had a recording of double potentials (DPs) in or around the left PV were included. Group I had five patients with the second deflection of DPs (D2) due to activation of the LAT, and Group II had five patients with D2 due to activation of the PV musculature. There were no significant difference in the isoelectric interval between DPs, the activation time, and amplitude of D2 between Groups I and II. During distal coronary sinus (CS) pacing, the CS ostium (CSO) to D2 interval was shorter compared with that during sinus rhythm in Group I (39 ± 19 vs 71 ± 25 ms, P = 0.04), but was longer in Group II (96 ± 16 vs 44 ± 19 ms, P = 0.04). During ectopic activation, three patients in Group I, but no Group II patients, had transformation of recorded DPs into triple potentials. Radiofrequency ablation guided by the earliest activation of the LAT potential was performed with transient suppression of PAF, but ablation guided by the earliest activation of the PV potentials had a high success rate in eliminating PAF. In conclusion, differentiating the LAT from the PV potentials for initiation of PAF is feasible by an electrophysiological approach, and may be important for radiofrequency ablation of PAF.
The Bayesian Approach Improves the Electrocardiographic Diagnosis of Broad Complex Tachycardia
Authors: LAU ERNEST W. , PATHAMANATHAN RAVI K. , NG G. ANDRÉ , COOPER JOANNE , SKEHAN J. DOUGLAS , GRIFFITH MICHAEL J.
Published: July 2003

LAU, E.W., et al.: The Bayesian Approach Improves the Electrocardiographic Diagnosis of Brand Complex Tachycardia. Despite numerous attempts at devising algorithms for diagnosing broad complex tachycardia (BCT) on the basis of the electrocardiogram (ECG), misdiagnosis is still common. The reason for this may lie with difficulty in implementing existent algorithms in practice, due to imperfect ascertainment of ECG features within them. An attempt was made to approach the problem afresh with the Bayesian inference by the construction of a diagnostic algorithm centered around the likelihood ratio (LR). Previously studied ECG features most effective in discriminating ventricular tachycardia (VT) from supraventricular tachycardia with aberrant conduction (SVTAC), according to their LR values, were selected for inclusion into a Bayesian diagnostic algorithm. A test set of 244 BCT ECGs was assembled and shown to three independent observers who were blinded to the diagnoses made at electrophysiological study. Their diagnostic accuracy by the Bayesian algorithm was compared against that by clinical judgement with the diagnoses from EPS as the criterial standard. Clinical judgement correctly diagnosed 35% of SVTAC, 85% of VT, and 47% of fascicular tachycardia. In comparison, by the Bayesian algorithm devised, 52% of SVTAC, 95% of VT, and 97% of fascicular tachycardia were correctly diagnosed. The Bayesian algorithm devised has proved to be superior to the clinical judgement of the observers who participated in this study, and theoretically will obviate the problem of imperfect ascertainment of ECG features. Hence, it holds the promise for being an effective tool for routine use in clinical practice.
Paradoxical AV Delay Shortening of a Pacemaker
Authors: BAROLD S. SERGE , ABE HARUHIKO , NAGATOMO TOSHIHISA
Published: July 2003

Barold, S.S., et al.: Paradoxical AV Delay Shortening of a Pacemaker. Paradoxical shortening of the paced AV delay (atrial paced‐ventricular paced or Ap‐Vp interval) was observed at rest in the DDD and DDDR modes in three patients with implanted CPI Vigor DR pacemakers programmed with a long AV delay and a relatively narrow difference between the lower and upper rates. This behavior is related to the VA extension algorithm designed to prevent the sensor‐driven atrial pacing rate from exceeding the programmed upper rate whenever a sensed conducted QRS complex continually follows an atrial stimulus. We found that this algorithm also becomes manifest at rest and may cause shortening of the Ap‐Vp intervals. The VA extension algorithm is best conceptualized in terms of a separate atrial upper rate that functions on exercise and at rest. The atrial and ventricular upper rates are equal but the atrial upper rate is initiated by an atrial‐paced or sensed event and the ventricular upper rate is initiated by a paced or sensed ventricular event. Under certain circumstances delay in the release of the atrial stimulus Ap to conform to the atrial upper rate interval produces variable abbreviation of the paced AV (Ap‐Vp) delays with resultant variation in the duration of the atrial escape intervals despite fundamental ventricular‐based lower rate timing.
Time Dependent Changes in Duration of Ventricular Repolarization After AV Node Ablation: Insights into the Possible Mechanism of Postprocedural Sudden Death
Authors: DIZON JOSE , BLITZER MARK , RUBIN DAVID , COROMILAS JAMES , COSTEAS CONSTANTINO , KASSOTIS JOHN , REIFFEL JAMES
Published: July 2003

DIZON, J., et al.: Time Dependent Changes in Duration of Ventricular Repolarization After AV Node Ablation: Insights into the Possible Mechanism of Postprocedural Sudden Death. Although effective, there is a disturbing incidence of sudden death after AV node ablation. The mechanism may be related to proarrhythmia associated with prolongation in ventricular repolarization from the sudden decrease in heart rate. To examine this issue, we studied 15 patients undergoing complete radiofrequency ablation of the AV node for rapid atrial arrhythmias. Twelve‐lead ECGs of paced rhythms at rates of 60, 80, 100, and 120 beats/min were recorded at time points of 30 minutes, 24 hours, 1 week, and 1 month after ablation. The QT interval was measured in the limb and precordial leads with the best T wave offset. The change in the QT interval (ΔQT) relative to the measurement at 30‐minute postablation was calculated. For comparison, a similar procedure was performed on patients receiving pacemakers for primary bradycardia (n = 5). The mean QT interval at 60 beats/min, 30‐minutes postablation was significantly longer than at time points thereafter (482 ± 39 vs 446 ± 28 ms at 1 month, limb leads, for example, P < 0.05). Analysis of ΔQT revealed a significant shortening of the QT interval at nearly every paced rate at every time point relative to the value at 30‐minute postablation. The QT intervals shortened and stabilized after 24 hours. Neither the QT interval nor ΔQT changed significantly in patients paced for primary bradycardia. We conclude that there is a relative increase in the duration of ventricular repolarization after AV node ablation, which then decreases and stabilizes after 24 hours. Such changes are not seen in patients being paced for primary bradycardia. This data is consistent with the hypothesis that sudden death after AV node ablation may be related to proarrhythmia from prolonged ventricular repolarization.
Paroxysmal Supraventricular Tachycardia in Identical Twins with the Same Left Lateral Accessory Pathways and Innocent Dual Atrioventricular Pathways
Authors: LU CHUN‐WEI , WU MEI‐HWAN , CHU SHU‐HSUN
Published: July 2003

LU, C.‐W., et al.: Paroxysmal Supraventricular Tachycardia in Identical Twins with the Same Left Lateral Accessory Pathways and Innocent Dual Atrioventricular Pathways. We report on 16‐year‐old, female identical twins who both have atrioventricular reentrant tachycardia caused by the same left lateral atrioventricular accessory pathway. The Kent pathway in twin A was a unidirectional retrograde accessory pathway. A manifest Kent pathway was demonstrated in twin B. Both pathways were successfully ablated by radiofrequency (RF) energy and without recurrence. In addition, innocent dual AV nodal pathways were shown in both patients. These findings suggest that genetic factors may play a role in the pathogenesis of the formation of accessory atrioventricular pathways and dual AV nodal pathways.
Demonstration of Myocardial Ischemia by an Internal Loop Recorder
Authors: VLAY STEPHEN C. , LAWSON WILLIAM E.
Published: July 2003

VLAY, S.C., et al.: Demonstration of Myocardial Ischemia by an Internal Loop Recorder. An internal loop recorder (ILR) implanted to evaluate syncope was activated during an episode of chest pain. Analysis of the recorded event revealed a marked increase in the amount of ST‐segment depression over baseline. In addition to rhythm analysis, the ILR may be able to assess myocardial ischemia. Further refinements of filtering may make analysis more accurate.
Opposite Effects of Myocardial Stretch and Verapamil on the Complexity of the Ventricular Fibrillatory Pattern: An Experimental Study
Authors: CHORRO FRANCISCO J. , CANOVES JOAQUÍN , GUERRERO JUAN , MAINAR LUIS , SANCHIS JUAN , SORIA EMILIO , SUCH LUIS M. , ROSADO ALFREDO , SUCH LUIS , LÓPEZ‐MERINO VICENTE
Published: July 2003

CHORRO, F.J., et al.: Opposite Effects of Myocardial Stretch And Verapamil on The Complexity of The Ventricular Fibrillatory Pattern: An Experimental Study. An experimental model is used to analyze the effects of ventricular stretching and verapamil on the activation patterns during VF. Ten Langendorff‐perfused rabbit hearts were used to record VF activity with an epicardial multiple electrode before, during, and after stretching with an intraventricular balloon, under both control conditions and during verapamil (Vp) infusion (0.4–0.8 μmol). The analyzed parameters were dominant frequency (FrD) spectral analysis, the median (MN) of the VF intervals, and the type of activation maps during VF (I = one wavelet without block lines, II = two simultaneous wavelets with block lines, III = three or more wavelets with block lines). Stretch accelerates VF (FrD: 22.8 ± 6.4 vs 15.2 ± 1.0 Hz, P < 0.01; MN: 48 ± 13 vs 68 ± 6 ms, P < 0.01). On fitting the FrD time changes to an exponential model after applying and suppressing stretch, the time constants (stretch: 101.2 ± 19.6 s; stretch suppression: 97.8 ± 33.2 s) do not differ significantly. Stretching induces a significant variation in the complexity of the VF activation maps with type III increments and type I and II decrements (control: I = 17.5%, II = 50.5%, III = 32%; stretch: I = 7%, II = 36.5%, III = 56.5%, P < 0.001). Vp accelerates VF (FrD: 20.9 ± 1.9 Hz, P < 0.001 vs control; MN: 50 ± 5 ms, P < 0.001 vs control) and diminishes activation maps complexity (I = 25.5%, II = 60.5%, III = 14%, P < 0.001 vs control). On applying stretch during Vp perfusion, the fibrillatory process is not accelerated to any greater degree. However, type I and II map decrements and type III increments are recorded, though reaching percentages similar to control (I = 16.5%, II = 53%, III = 30.5%, NS vs control). The following conclusions were found: (1) myocardial stretching accelerates VF and increases the complexity of the VF activation pattern; (2) time changes in the FrD of VF during and upon suppressing stretch fit an exponential model with similar time constants; and (3) although stretching and verapamil accelerate the VF process, they exert opposite effects upon the complexity of the fibrillatory pattern.
Atrioventricular Interval Optimization in the Right Atrial Appendage and Interatrial Septum Pacing: A Comparison Between Echo and Peak Endocardial Acceleration Measurements
Authors: PADELETTI LUIGI , PORCIANI MARIA CRISTINA , RITTER PHILIPPE , MICHELUCCI ANTONIO , COLELLA ANDREA , PIERAGNOLI PAOLO , COSTOLI ALESSANDRO , CIAPETTI CRISTINA , SABINI ALESSANDRA , DEMARCHI GABRIELE , GILLIO‐MEINA LAURA , GAGGINI GUIDO , GENSINI GIAN FRANCO
Published: July 2003

PADELETTI, et al.: Atrioventricular Interval Optimization in the Right Atrial Appendage and Interatrial Septum Pacing: A Comparison Between ECHC and Peak Endocardial Acceleration. Interatrial septum pacing (IASP) reduces interatrial conduction time and consequently may interfere with atrioventricular delay (AVD) optimization. We studied 14 patients with an implanted BEST Living system device able to measure peak endocardial acceleration (PEA) signal. The aims of our study were to compare the (1) optimal AVD (OAVD) in right atrial appendage pacing (RAAP) and IASP, and (2) OAVD derived by the PEA signal versus OAVD derived by Echo/Doppler evaluation of the left ventricular filling time (LVFT) and cardiac output (CO). Measurements were performed in DDD VDD modes Eight patients (group A) had RAAP and six patients (group B) had IASP. In group A, OAVD measured by LVFT, CO, and PEA was 185 ± 23 ms, 177 ± 19 ms, and 192 ± 23 ms in DDD and 147 ± 19 ms, 135 ± 27 ms, and 146 ± 20 ms in VDD, respectively. OAVD measured by LVFT, CO, and PEA was significantly longer in DDD mode than in VDD (P < 0.01, P < 0.01, P < 0.001). In group B, OAVD measured by LVFT, CO, and PEA was 116 ± 19 ms, 113 ± 10 ms, and 130 ± 30ms in DDD and 106 ± 16 ms, 96 ± 15 ms, and 108 ± 26 ms in VDD, respectively. No statistical differences were observed between DDD and VDD. Significant correlations between OAVDs PEA derived and OAVDs LVFT and CO derived were observed (r = 0.71, r = 0.69, respectively). When new techniques of atrial stimulation, as IASP, are used an OAVD shorter and similar in VDD and DDD has to be considered. The BEST Living system could provide a valid method to ensure, in every moment, the exact required OAVD to maximize atrial contribution to CO.
Studies on Hemodynamic Instability in Paroxysmal Supraventricular Tachycardia: Noninvasive Evaluations by Head‐Up Tilt Testing and Power Spectrum Analysis on Electrocardiographic RR Variation
Authors: DOI ATSUSHI , MIYAMOTO KENJIROH , UNO KIKUYA , NAKATA TOMOAKI , TSUCHIHASHI KAZUFUMI , SHIMAMOTO KAZUAKI
Published: July 2003

DOI, A., et al.: Studies on Hemodynamic Instability in Paroxysmal Supraventricular Tachycardia: Noninvasive Evaluations by Head‐Up Tilt Testing and Power Spectrum Analysis on Electrocardiographic RR Variation. Hemodynamic instability is a crucial determinant of the best therapeutic option in paroxysmal supraventricular tachycardia (PSVT). However, it is still unclear if hemodynamic instability is tachycardia dependent or independent. We performed frequency‐domain analysis of electrocardiographic RR variations during induced PSVT and head‐up tilt tests after successful ablation to investigate the role of autonomic vasomotor function in hemodynamic instability during PSVT. Thirty‐six patients with (syncope group, n = 18) and without (nonsyncope group, n = 18) syncope and/or presyncope during PSVT were enrolled in this study. Serial blood pressure, heart rate, and variations in heart rate during induced PSVT and head‐up tilt tests were examined. Initial blood pressure fall and heart rate changes during induced PSVT were greater in the syncope group than in the nonsyncope group. A significant positive linear relationship was found between these two. Delayed blood pressure fall was observed in the syncope group, independent of heart rate changes. Syncope in PSVT could be predicted from the results of head‐up tilt tests with 82% accuracy. Heart rate responses after isoproterenol infusion were significantly greater in the syncope group than in the nonsyncope group. The changes in low frequency to high frequency (LF:HF) values during induced PSVT and head‐up tilt tests were significantly greater in the syncope group than in the nonsyncope group, and an exponential correlation was found between LF:HF changes in both tests. We conclude that PSVT rate and vasomotor reaction are related with hemodynamic instability during PSVT and head‐up tilt testing is a useful method for determining if patients will have syncope during PSVT.
Reduction of Radiation Exposure in the Cardiac Electrophysiology Laboratory
Authors: WITTKAMPF FRED H.M. , WEVER ERIC F.D. , VOS KEES , GELEIJNS JACOB , SCHALIJ MARTIN J. , VAN DER TOL JAN , ROBLES DE MEDINA ETIENNE O.
Published: July 2003

WITTKAMPF, F.H.M., et al. Reduction of Radiation Exposure in the Cardiac Electrophysiology Laboratory. The purpose of this study was to determine the effects of various protective measures on patient and operator radiation dose levels in catheter ablation procedures. Catheter ablation procedures are associated with significant radiation levels. The patient's skin and operator radiation levels were measured (1) at baseline, (2) after primary beam filtration by 0.3‐mm copper sheet and 2‐mm aluminium plate and implementation of the LocaLisa system, and (3) after reduction of the left anterior oblique fluoroscopic pulse rate and installation of a lead glass screen. Additionally, a comparative analysis of radiation exposure levels was performed in the seven Dutch catheter ablation centers. Filtration of both primary beams resulted in a more than two‐fold reduction in patient skin dose. Together with the LocaLisa system, this resulted in a six‐fold reduction in patient and operator dose. As expected, lowering of the left anterior oblique pulse rate from 25 to 12.5 Hz reduced the corresponding patient skin dose with a factor 2 while the leadglass protection caused an extra factor 2 reduction for the operator. Large differences were observed between fluoroscopy systems used for catheter ablation in the Netherlands. Depending on patient body mass and fluoroscopy system, patient skin dose varied between 0.2 and 8.4 Gy/hour. Proper measures may allow for a significant reduction of patient and operator radiation exposure in catheter ablation procedures. The large influence of body mass and equipment on patient's skin dose requires a more direct monitoring of skin dose than total fluoroscopy time.
Changes in AV Node Conduction Curves Following Slow Pathway Modification
Authors: GELLER J. CHRISTOPH , GOETTE ANDREAS , REEK SVEN , FUNKE CORINNA , HARTUNG WOLFGANG M. , KLEIN HELMUT U.
Published: July 2003

GELLER, J.C., et al.: Changes in AV Node Conduction Curves Following Slow Pathway Modification. Dual AV node physiology often persists after successful slow pathway (SP) ablation, and the mechanism of tachycardia elimination is unresolved. Therefore, AV node conduction curves were analyzed following successful ablation (4 ± 1 energy applications) in 85 consecutive patients (58 women, age 50 ± 2 years) with typical AVNRT. Twenty‐seven patients (32%) had complete elimination (group 1) whereas 58 (68%) patients had persistence (group 2) of dual AV node physiology. A significant increase in the AV node Wenckebach cycle length (WB‐CL) was observed in both groups (310 ± 9 to 351 ± 15 ms in group 1, and 325 ± 8 to 369 ± 9 ms in group 2, P < 0.05). A decrease in the fast pathway (FP) ERP (339 ± 15 to 279 ± 12 ms) and an increase in the maximum FP AH interval (141 ± 5 to 171 ± 7) were observed only in group 1 (P < 0.05). In group 2, no change in the SP ERP (267 ± 7 to 280 ± 10 ms) was observed, and the change in the maximum SP‐AH following ablation showed a significant inverse relation to the maximum SP‐AH at baseline in group 2. In conclusion, (1) an increase in the WB‐CL is observed independent of the persistence or elimination of dual physiology after successful ablation; (2) when dual physiology is eliminated, significant changes in the FP ERP and the maximum FP‐AH occur; (3) when dual physiology persists, FP physiology and the SP ERP remain unchanged, and a significant inverse relation between the change in the maximum SP‐AH following ablation and the maximum baseline SP‐AH is observed.
Double Ventricular Response by a Single Ventricular Extrastimulus to the Inner Loop of Reentry in a Patient Without Apparent Heart Disease
Authors: SHIMIZU AKIHIKO , YAMAGATA TOSHIHIKO , YOSHIGA YASUHIKO , HAYANO TOMOKO , OHMURA MASATO , KIMURA MASAYASU , ITAGAKI KAZUO , MATSUZAKI MASUNORI
Published: July 2003

SHIMIZU, A., et al.: Double Ventricular Response by a Single Ventricular Extrastimulus to the Inner Loop of Reentry in a Patient Without Apparent Heart Disease. In a patient without apparent heart disease, a ventricular extrastimulus delivered from the left ventricular apex where the electrogram was recorded 30 ms after the onset of the QRS complex during VT advanced the second QRS complex, but not the first QRS complex. The morphology of the second QRS complex was the same as that of VT. The postpacing interval was the same as the cycle length of the VT. These findings indicated that the site of stimulation was at the inner loop of the reentry circuit of the VT. A ventricular extrastimulus with a shorter coupling interval advanced the first and second QRS complexes, indicating that the ventricle was activated by antidromic and orthodromic activation from the extrastimulus. Radiofrequency ablation at that site of stimulation terminated the VT and no further VT could be induced.
Modified Implantation of a Transvenous Defibrillator in a Patient After Tricuspid Valve Replacement
Authors: SCHREIBER CHRISTIAN , MEHMANESCH HORMOZ , KOLB CHRISTOF , SCHMITT CLAUS , LANGE RÜDIGER
Published: July 2003

SCHREIBER, C., et al.: Modified Implantation of a Transvenous Defibrillator in a Patient after Tricuspid Valve Replacement. A different approach to transvenous implantation in a patient after tricuspid valve replacement with a mechanical prosthesis is described. To our knowledge, this is the first report in this setting, using a CPI system with a single shock electrode only.
Treatment of Drug Refractory Ventricular Tachycardia by Biventricular Pacing
Authors: GARRIGUE STEPHANE , BAROLD S. SERGE , HOCINI MELEZE , JAÏS PIERRE , HAÏSSAGUERRE MICHEL , CLEMENTY JACQUES
Published: July 2003

GARRIGUE, S., et al.: Treatment of Drug Refractory Ventricular Tachycardia by Biventricular Pacing. In a patient with severe congestive heart failure and ischemic disease, frequent episodes of ventricular tachycardia were completely suppressed by an implantable cardioverter defibrillator with biventricular pacing
When Should Heparin Preferably Be Administered During Radiofrequency Catheter Ablation?
Authors: ANFINSEN OLE‐GUNNAR , GJESDAL KNUT , AASS HALFDAN , BROSSTAD FRANK , ORNING OTTO M. , AMLIE JAN P.
Published: July 2003

ANFINSEN, O.‐G., et al.: When Should Heparin Preferably be Administered During Radiofrequency Catheter Ablation? RF catheter ablation is complicated by thromboembolism in about 1% of patients. Limited knowledge exists concerning when and how to use anticoagulation or antithrombotic treatment. We studied the activation of coagulation (prothrombin fragment 1 + 2 [PF1 + 2] and D‐dimer), platelets (β‐thromboglobulin [β‐TG]) and fibrinolysis (plasmin‐antiplasmin complexes [PAP]) during RF ablation of accessory pathways in 30 patients. They were randomized to receive heparin (100 IU/kg, intravenously) (1) immediately after introduction of the femoral venous sheaths (group I) or (2) after the initial electrophysiological study, prior to the delivery of RF current (groups II and III). Group II additionally received saline irrigation of all femoral sheaths. After the initial bolus, 1,000 IU of heparin was supplied hourly in all groups. Within groups II and III, median plasma values of PF1 + 2 and β‐TG more than tripled (P ≤ 0.007) during the diagnostic study and gradually declined during heparin administration despite RF current delivery. Median D‐dimer tripled (P = 0.005) and PAP doubled (NS) before heparin administration; then both remained around the upper reference values. In the early heparin group, however, PF1 + 2, Ddimer, and PAP did not rise at all, and β‐TG showed only a slight increase towards the end of the procedure. The differences between group I versus groups II and III were statistically significant prior to the first RF current delivery (PF1 + 2, D‐dimer, and β‐TG) and by the end of the procedure (PF1 + 2, D‐dimer, and PAP). In conclusion, “late” heparin administration allows hemostatic activation during the initial catheterization and diagnostic study. By administering intravenous heparin immediately after introduction of the venous sheaths, hemostatic activation is significantly decreased. Saline irrigation of the venous sheaths added nothing to late heparin administration.