bluuebunny/crossref_metadata_2025_split huggingface dataset:
Risk Factors for HIV/AIDS and Hepatitis C Among the Chronic Mentally Ill
Authors: Davidson Sandra , Judd Fiona , Jolley Damien , Hocking Barbara , Thompson Sandra , Hyland Brendan 
Published: August 2003

Objective: The objective of this study was to document the prevalence of risk factors for HIV/AIDS and hepatitis C among people with chronic mental illness treated in a community setting. Method: 234 patients attending four community mental health clinics in the North-western Health Care Network in Melbourne, Australia, completed an interviewer-administered questionnaire which covered demographics, risk behaviour and psychiatric diagnosis. Results: The sample was 58% male, and 79% of the sample had a primary diagnosis of schizophrenia. Forty-three per cent of mentally ill men and 51% of mentally ill women in the survey had been sexually active in the 12 months preceding the survey. One-fifth of mentally ill men and 57% of mentally ill women who had sex with casual partners never used condoms. People with mental illness were eight times more likely than the general population to have ever injected illicit drugs and the mentally ill had a lifetime prevalence of sharing needles of 7.4%. Conclusions: The prevalence of risk behaviours among the study group indicate that people with chronic mental illness should be regarded as a high-risk group for HIV/AIDS and hepatitis C. It is essential that adequate resources and strategies are targeted to the mentally ill as they are for other high-risk groups.
Learned predator recognition and antipredator responses in fishes
Authors: Kelley Jennifer L , Magurran Anne E 
Published: August 2003

AbstractEarly research into the causes of geographical variation in antipredator behaviour in fishes revealed that population differences have an underlying genetic basis. However, evidence from a variety of fish species suggests that learning plays an important role in the development of antipredator responses. Here, we consider the opportunities for learning during the three main stages of a predator–prey interaction: detection, recognition and assessment, and attack avoidance. Much of the evidence for learning is based on the recognition and assessment stage of the predator–prey interaction, but this may reflect methodological biases. We also examine the relative roles of different sensory cues, in particular, vision and olfaction, and the importance of individual vs. social learning. We provide evidence that visual predator recognition skills are largely built on unlearned predispositions, whereas olfactory recognition typically involves experience with conspecific alarm cues. Populations display variation in their propensity to learn, and we predict that ecological factors are likely to mediate the balance between individual and social learning.
Spatial cognition and its neural basis in teleost fishes
Authors: Broglio Cristina , Rodríguez Fernando , Salas Cosme 
Published: August 2003

AbstractThe present review is focused on recent laboratory studies revealing that the spatial behaviour of fishes is as complex and elaborate as described in land vertebrates. In addition, the data presented here indicate that the remarkable richness and plasticity of spatial behaviour in fishes are based on learning and memory mechanisms and cognitive processes that depend on particular brain circuits, possibly homologous to those identified in mammals and birds. For example, there is evidence that the fish hippocampal pallium is essential for processing and encoding complex spatial information to form map‐like representations of the environment. In contrast, body‐centred orientation strategies or emotional learning are subserved by different cerebral structures, such as the optic tectum, the cerebellum or the amygdalar pallium. These results that suggest a striking similarity in some cognitive processes and their neural basis between fish and land vertebrates are consistent with the possibility that these vertebrate groups share a common basic pattern of brain and behaviour organisation inherited from a common ancestor and conserved through a long history of separate evolution.
Diagnostic Performance of a Dual‐Chamber Cardioverter Defibrillator Programmed with Nominal Settings: A European Prospective Study
Authors: SADOUL NICOLAS , JUNG WERNER , JORDAENS LUC , LEENHARDT ANTOINE , SANTINI MASSIMO , WOLPERT CHRISTIAN , ALIOT ETIENNE 
Published: August 2003

Arrhythmia Discrimination by ICD.
Introduction: Despite technologic developments, accurate discrimination of ventricular tachyarrhythmia from rapid rhythms of nonventricular origin remains a challenge. We sought to examine the sensitivity and specificity of a dual‐chamber arrhythmia detection algorithm, the PARAD algorithm, incorporated in a dual‐chamber implantable cardioverter defibrillator, the Defender (ELA Medical). Methods and Results:All detailed tachycardia episodes (i.e., with stored atrial and ventricular channel markers and electrograms) retrieved from the Holter memory of the device were analyzed from 95 patients (86 men and 9 women; age 62 ± 12 years) implanted with the Defender with the algorithm programmed at nominal settings. Over a follow‐up of 15 ± 8 months, 559 detailed sustained tachycardia episodes detected in the tachycardia zone were gathered in 62 patients. Of the 300 ventricular tachycardia (VT) episodes, 298 were appropriately classified as VT by the algorithm. Of the 259 supraventricular tachycardia (SVT) episodes, 231 were appropriately classified as SVT. In 8 patients, 28 episodes of SVT were misclassified as VT: 25 atrial fibrillation episodes (6 patients), 2 sinus tachycardia (1 patient), and 1 atrial tachycardia. Calculated sensitivity and specificity were 99.3% and 89.2% on a per episode basis and 99.8% (95% confidence interval: 97.8 to 100) and 91.6% (95% confidence interval: 86.0 to 97.3) on a per patient basis, respectively. Conclusion: In this selected population of patients, the PARAD algorithm was safe and reliable for detection of a wide spectrum of tachyarrhythmias. Its specificity was high, particularly with respect to sinus tachycardia detection, but it must be improved with respect to detection of atrial fibrillation.
Implantable Cardioverter Defibrillator Utilization Based on Discharge Diagnoses from Medicare and Managed Care Patients
Authors: RUSKIN JEREMY N. , CAMM A. JOHN , ZIPES DOUGLAS P. , HALLSTROM ALFRED P. , MCGRORY‐USSET MARY E. 
Published: August 2003

ICD Utilization.
Introduction: Implantable cardioverter defibrillators (ICDs) have become an accepted therapy for patients at high risk of sudden cardiac death. To assess the current utilization of this therapy, we estimated the number of patients at risk of sudden death using an historical claims‐based study and compared these results to current ICD usage volumes. Methods and Results: Managed care and Medicare databases (claims related to 4.6 million covered U.S. lives during a 12‐month period) were analyzed to identify patients who had either a primary or secondary diagnosis of ventricular tachycardia, ventricular fibrillation, ventricular flutter, or cardiac arrest. These patients were further required to have a diagnosis code indicating a previous myocardial infarction or congestive heart failure. Patients who died during the study period or did not have medical insurance were excluded. In the base case scenario, 1,226 patients per million population were identified as potential ICD candidates. Sensitivity analyses reduced that value to a range from 736 to 1,140 ICD candidates per million population. Sensitivity factors considered included acute myocardial infarction, comorbidities, age, secondary ventricular tachycardia/ventricular fibrillation diagnosis, and varying degrees of left ventricular dysfunction. These results contrast with an ICD usage rate of 416 per million population in the United States and lower rates in other countries. Conclusion: This study suggests that, based on discharge diagnoses, many patients who could benefit from ICDs are not receiving this therapy. Diverse reasons for this underutilization should be addressed to improve access to, and appropriate use of, this therapy.
T Wave Alternans as a Predictor of Spontaneous Ventricular Tachycardia in a Canine Model of Sudden Cardiac Death
Authors: TSAI JEROME , CAO JI‐MIN , ZHOU SHENGMEI , SWISSA MOSHE , CATES ADAM W. , KENKNIGHT BRUCE H. , CHEN LAN S. , KARAGUEUZIAN HRAYR S. , CHEN PENG‐SHENG 
Published: August 2003

T Wave Alternans as Predictor of Spontaneous VT.
Introduction: We recently developed an ambulatory canine model of spontaneous ventricular tachycardia (VT) and sudden cardiac death by creating myocardial infarction, complete AV block, and infusion of nerve growth factor to the left stellate ganglion. Whether or not T wave alternans is associated with the spontaneously occurring episodes of VT in our model was unclear. Methods and Results: Through intracardiac electrograms obtained from an implantable cardioverter defibrillator, we manually measured T wave amplitudes prior to VT and while the dogs were at rest (baseline, no VT). Of the 79 VT episodes analyzed, 28 (35.4%) exhibited repolarization alternans. In contrast, only 3 (4.7%) of 64 baseline data cases displayed alternans (P < 0.0001). The magnitude of T wave alternans for dogs that died of sudden cardiac death, dogs that did not die suddenly, and for the total 28 episodes that exhibited repolarization alternans were 4.8 ± 2.8 mm, 4.9 ± 3.5 mm, and 4.9 ± 3.3 mm, respectively (P = NS). We also found the sensitivity, specificity, positive predictive value, negative predictive value, and relative risk of repolarization alternans in predicting VT to be 35.4%, 95.3%, 90.3%, 54.5%, and 1.98, respectively. The ventricular rate prior to VT (65 ± 11 beats/min) was significantly higher than that at rest (49 ± 12 beats/min; P < 0.0001). Conclusion: T wave alternans often occurred immediately before the onset of VT in dogs with myocardial infarction, complete AV block, and nerve growth factor infusion to the left stellate ganglion. Increased sympathetic activity might be responsible for the occurrence of the T wave alternans.
Pulmonary Vein Paced Activation Sequence Mapping: Comparison with Activation Sequences During Onset of Focal Atrial Fibrillation
Authors: DEEN VINCENT R. , MORTON JOSEPH B. , VOHRA JITENDRA K. , KALMAN JONATHAN M. 
Published: August 2003

Activation Sequence Mapping of Focal AF.
Introduction: Atrial fibrillation (AF) may originate from a single focus, with the vast majority observed within the pulmonary veins. To facilitate mapping, we hypothesized that there would be a characteristic right atrial endocardial activation sequence pattern associated with pacing and spontaneous focal activity from each of the four pulmonary veins. Methods and Results: In 10 patients with focal AF, a standardized set of catheters was positioned in the right atrium. These included a 20–pole catheter along the crista terminalis, a decapolar catheter in the coronary sinus (CS), and a His‐bundle electrode. Pacing (700 and 300 msec) was performed with a mapping catheter from each of the four pulmonary veins. Activation sequence maps were created by measurement of activation times to each of the recording bipoles with the proximal CS bipole as the arbitrary reference point. Similar maps were constructed for the activation sequence of the pulmonary vein ectopic that initiated AF. There was a characteristic right atrial activation map created by pacing each pulmonary vein that corresponded closely with the map from the same pulmonary vein during initiation of focal AF. The pulmonary vein of origin could be distinguished on the basis of this characteristic pattern and some stereotypic observations. CS activation occurred proximal to distal for right pulmonary veins and distal to proximal for left pulmonary veins. Significant differences in activation timing between the CS and crista terminalis differentiated upper from lower pulmonary veins. Conclusion: There is a characteristic right atrial activation map for activity arising from each of the four pulmonary veins that corresponded closely with the map from the same pulmonary vein during initiation of focal AF. These findings may facilitate mapping and ablation of focal AF.
Effects of Verapamil and Ibutilide on Atrial Fibrillation and Postfibrillation Atrial Refractoriness
Authors: STICHERLING CHRISTIAN , HSU WILLIAM , TADA HIROSHI , BARES ANTON C. , ORAL HAKAN , PELOSI FRANK , KNIGHT BRADLEY P. , STRICKBERGER S. ADAM , MORADY FRED 
Published: August 2003

Verapamil and Ibutilide.
Introduction: Early recurrence of atrial fibrillation (AF) after cardioversion may be related to shortening of the atrial effective refractory period (ERP). This study compared the effects of verapamil and ibutilide on AF cycle length (AFCL), atrial ERP, and susceptibility to recurrent AF. Methods and Results: In 33 adults, the atrial ERP was measured at basic drive CLs of 350 and 500 msec before and after a brief episode of pacing‐induced AF. During AF, verapamil, ibutilide, or saline was infused in 11 patients each. Shortening of the post‐AF atrial ERP was attenuated by verapamil and prevented by ibutilide. AFCL shortened by 32 ± 21 msec in the verapamil group (P < 0.01), prolonged by 44 ± 14 msec in the ibutilide group (P < 0.001), and did not change in the control group. AF converted to sinus rhythm within 10 minutes less often after verapamil (0%) than after ibutilide (82%) or than in the control group (73%). Post‐AF, AF lasting > 10 minutes was induced more often in the verapamil group than in the ibutilide group (26% vs 0%; P = 0.01). Another 10 patients received verapamil or ibutilide in the absence of AF. Atrial ERP was unchanged after verapamil and prolonged after ibutilide. Conclusion: Verapamil shortens AFCL and impedes the conversion of induced AF, whereas ibutilide prolongs AFCL and does not impede the early conversion of induced AF. Ibutilide is more effective than verapamil in preventing post‐AF shortening of the atrial ERP and reducing the susceptibility toward reinduction of AF.
Reexpression of the Nifedipine‐Resistant Calcium Channel During Dedifferentiation of Adult Rat Ventricular Cardiomyocytes
Authors: PIGNIER CHRISTOPHE , ANCEY CÉCILE , FARES NASSIM , BESCOND JOCELYN , POTREAU DANIEL 
Published: August 2003

Nifedipine‐Resistant Calcium Current.
Introduction: Using an adult rat ventricular culture model and whole‐cell patch‐clamp technique, we investigated whether the nifedipine‐resistant calcium current observed at the neonatal stage but not at the adult stage could be reobserved under dedifferentiating conditions. Methods and Results: Application of 2 μM nifedipine totally inhibited the inward calcium current (carried by 5 mM Ba2+) in freshly isolated cells from adult rat heart, but it failed to block it completely when cells are cultured for 8 to 12 days. Dose‐response curves of nifedipine in the range from 2 to 50 μM showed a residual current that represented, in the presence of 2 μM nifedipine, 16.4% ± 1.8% (n = 10) and 20.4% ± 1.5% (n = 10) of the total current in 8‐ and 12‐day‐old cultured cells, respectively. In these conditions, its density at 0 mV increased slightly during culture (−2.1 ± 0.2 pA/pF, n = 7, and −3.2 ± 0.4 pA/pF, n = 8, after 8 and 12 days in culture, respectively), without modification in the current‐tovoltage curve, as well as in kinetics properties. Conclusion: These results show that nifedipine‐resistant calcium current, which has been shown to be developmentally regulated in rat ventricular cardiomyocytes, can be reexpressed in cultured‐dedifferentiated cells. Its possible expression and implication in physiopathologic function are suggested.
Atrioventricular Nodal Reentrant Tachycardia in Children: Effect of Slow Pathway Ablation on Fast Pathway Function
Authors: VAN HARE GEORGE F. , CHIESA NANCY A. , CAMPBELL ROBERT M. , KANTER RONALD J. , CECCHIN FRANK ,   FOR THE PEDIATRIC ELECTROPHYSIOLOGY SOCIETY
Published: August 2003

AV Nodal Reentry in Children.
Introduction: Prior studies in adults have shown significant shortening of the fast pathway effective refractory period after successful slow pathway ablation. As differences between adults and children exist in other characteristics of AV nodal reentrant tachycardia (AVNRT), we sought to characterize the effect of slow pathway ablation or modification in a multicenter study of pediatric patients. Methods and Results: Data from procedures in pediatric patients were gathered retrospectively from five institutions. Entry criteria were age < 21 years, typical AVNRT inducible with/without isoproterenol infusion, and attempted slow pathway ablation or modification. Dual AV nodal pathways were defined as those with > 50 msec jump in A2‐H2 with a 10‐msec decrease in A1‐A2. Successful ablation was defined as elimination of AVNRT inducibility. A total of 159 patients (age 4.4 to 21 years, mean 13.1) were studied and had attempted slow pathway ablation. AVNRT was inducible in the baseline state in 74 (47%) of 159 patients and with isoproterenol in the remainder. Dual AV nodal pathways were noted in 98 (62%) of 159 patients in the baseline state. Ablation was successful in 154 (97%) of 159 patients. In patients with dual AV nodal pathways and successful slow pathway ablation, the mean fast pathway effective refractory period was 343 ± 68 msec before ablation and 263 ± 64 msec after ablation. Mean decrease in the fast pathway effective refractory period was 81 ± 82 msec (P < 0.0001) and was not explained by changes in autonomic tone, as measured by changes in sinus cycle length during the ablation procedure. Electrophysiologic measurements were correlated with age. Fast pathway effective refractory period was related to age both before (P = 0.0044) and after ablation (P < 0.0001). AV block cycle length was related to age both before (P = 0.0005) and after ablation (P < 0.0001). However, in dual AV nodal pathway patients, the magnitude of change in the fast pathway effective refractory period after ablation was not related to age. Conclusion: Lack of clear dual AV node physiology is common in pediatric patients with inducible AVNRT (38%). Fast pathway effective refractory period shortens substantially in response to slow pathway ablation. The magnitude of change is large compared with adult reports and is not completely explained by changes in autonomic tone. Prospective studies in children using autonomic blockade are needed.
Prevalence of a Shared Isthmus in Postinfarction Patients with Pleiomorphic, Hemodynamically Tolerated Ventricular Tachycardias
Authors: BOGUN FRANK , LI YI‐GANG , GROENEFELD GERIAN , HOHNLOSER STEFAN H. , SCHUGER CLAUDIO , ORAL HAKAN , PELOSI FRANK , KNIGHT BRADLEY , STRICKBERGER S. ADAM , MORADY FRED 
Published: August 2003

Shared Isthmus.
Introduction: Multiple forms of ventricular tachycardia (VT) after myocardial infarction may result from multiple reentrant circuits that share an isthmus or from separate reentrant circuits. The prevalence of a shared isthmus in patients with multiple hemodynamically tolerated VTs has not been determined. Methods and Results: Criteria for a shared isthmus consisted of (1) concealed entrainment of > 1 VT at a single pacing site; (2) concealed entrainment during VT and a perfect pace map of another VT at the same pacing site; or (3) concealed entrainment of VT of a given morphology that had at least two cycle lengths that varied by at least 100 msec. In a series of 19 patients (16 men and 3 women; age 65 ± 14 years, ejection fraction 0.25 ± 0.09) with 54 VTs (mean cycle length 494 ± 98 msec), there was evidence of a shared isthmus in 23 VTs (43%) at 11 sites in 9 patients. Concealed entrainment of two different VTs was observed at 4 of 11 sites. At 5 of 11 sites there was concealed entrainment of one VT and a perfect pace map of another VT. At the remaining 2 of 11 sites, there was concealed entrainment of a VT that had two different cycle lengths. Nineteen of the 23 VTs were ablated successfully with radiofrequency energy applications at 11 sites. Conclusion: In postinfarction patients with pleiomorphic, hemodynamically stable VT, a shared isthmus may be present in approximately 40% of VTs.
Polymorphisms in Beta‐Adrenergic Receptor Genes in the Acquired Long QT Syndrome
Authors: KANKI HIDEAKI , YANG PING , XIE HONG‐GUANG , KIM RICHARD B. , GEORGE ALFRED L. , RODEN DAN M. 
Published: August 2003

Adrenergic Receptor Polymorphism and Arrhythmia.
Introduction: Sympathetic activation is a trigger for life‐threatening arrhythmias in many patients with the congenital long QT syndrome (LQTS), and an increase in heart rate has been reported just prior to torsades de pointes in patients with drug‐associated (acquired) LQTS (aLQTS). We compared the frequencies of five recognized nonsynonymous coding region polymorphisms in genes encoding the β1‐adrenergic and β2‐adrenergic receptors (AR) in 93 patients with aLQTS and 3 control groups: an ethically diverse set of individuals from middle Tennessee (n = 71), a subset of the Polymorphism Discovery Resource obtained from National Human Genome Research Institute (n = 89), and patients who tolerated QT‐prolonging drugs without aLQTS (non‐aLQTS group; n = 66). Methods and Results: Polymerase chain reaction‐restriction fragment length polymorphism was used to screen for Ser49Gly and Gly389Arg (β1‐AR) and Thr164Ile (β2‐AR). For Arg16Gly and Gln27Glu, polymorphic sites 33 nucleotides apart in the β2‐AR, single‐stranded conformational polymorphism was used to distinguish among the 4 possible haplotypes and 10 possible genotypes. Allele frequencies were similar among the 4 groups at the 2β1‐AR sites. The uncommon Ile164 variant in β2‐AR was slightly more frequent in patients (3.2%) than in any of the 3 control groups (0.6% to 2.3%). At the 16–27 neighboring sites in the β2‐AR, one haplotype (Arg16/Glu27) was not detected, as in previous studies; hence, only 6 genotypes were present. There were fewer Gly16/Gln27 homozygotes in the non‐aLQTS group (1.5%) than in two other control groups or the aLQTS group (8.5% to 10%). Conclusion: None of the five common nonsynonymous coding region polymorphisms in the β‐AR genes predict drug‐associated torsades de pointes, although the Gly16/Gln27 haplotype may be a risk factor.