Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pathways”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,189 records · Page 66Linked to original sources
PubMed2005

Use and development of clinical pathways by registered nurses in an acute paediatric setting.

Clinical pathways are widely regarded as providing valuable knowledge about specific types of patients and their care, as well as providing direct guidance in clinical practice. In Australia, the use of care pathways has occurred with seemingly minimal professional nursing debate as to their benefits in practice. Comments supporting the introduction of pathways into clinical practice have focused on assistance to decision making, facilitation of clinical judgements about care, assistance in improving practice and utility as educational tools, particularly for new staff, new graduates and casual employees. A survey of 259 nurses working in an acute paediatric setting sought to gain their views about pathways of care with regard to satisfaction with use, content of pathway, ability to use in practice, effect on practice and commitment to use. While the most positive findings to emerge from the research indicated that nurses liked clinical pathways because they saved time and reduced documentation requirements, issues were also raised about the need for a broader, more inclusive development process for pathways, and an improved education program for staff use. The implications to arise from these findings are important for senior staff and educators who are responsible for staff orientation programs and ongoing staff development as well as for those responsible for the development and implementation of clinical pathways into practice.

Attitude of Health Personnel↗
PubMed2004

Fast pathway-His bundle connections in the rabbit heart.

OBJECTIVES: The incidence and the physiologic roles for direct fast pathway-His bundle connections were examined in 102 rabbit hearts. METHODS: Extracellular bipolar and intracellular microelectrode recordings were made from the superfused rabbit AV junction. RESULTS: In 13 of 27 preparations demonstrating anterior extensions of the fast pathway, the retrograde HA ERP and 2:1 block cycle length were shortened (128 +/- 12 and 145 +/- 5 msec, respectively) versus the remaining 89 preparations (178 +/- 15 and 185 +/- 10 msec, respectively, p < 0.01). The former values were similar to the ERP and 2:1 block cycle length of fast pathway transitional cells (128 +/- 23 and 141 +/- 4 msec, respectively), suggestive of a direct fast pathway-His bundle connection. A deflection recorded between the A and H potentials of the His bundle electrogram could be dissociated from both atrial and His bundle activation. Intracellular microelectrode recordings and light microscopy confirmed the deflection to be an accessory pathway consisting of an anterior extension of fast pathway transitional cells connecting the atrium and His bundle. Transection along the AV groove anterior to the compact AV node ( N = 5) increased the retrograde ERP and Wenckebach block cycle length by severing the AH connection, or transection of the penetrating bundle ( N = 4) produced antegrade AH block without altering rapid retrograde conduction. CONCLUSIONS: Fast pathway-His bundle connections were present in 13 of 102 rabbit hearts, providing an anatomic and physiologic basis for rapid retrograde VA conduction and a possible retrograde pathway for sustained AV nodal reentrant tachycardia.

Afferent Pathways↗
PubMed2003

Perceptions on the development of a care pathway for people diagnosed with schizophrenia on acute psychiatric units.

Policy development and practice for hospital mental health care has shifted towards a user-focused and evidence-based direction. Important within this policy development has been a guideline for inpatient care, particularly the establishment of an inpatient Acute Care Forum. A vehicle to both commission and develop this agenda is the Implementation of a care pathway. A research study was designed to explore how a care pathway could be developed for inpatients diagnosed with schizophrenia. Interviews with a range of health care professionals and observation of the process of care pathway development were the data-collection tools. Analysis was driven by emergent themes across the data set. Themes were then presented as one possible interpretation of the factors to be considered for the development of a care pathway for people diagnosed with schizophrenia. Clinicians experienced many difficulties in finding and including evidence-based practice (EBP) within a care pathway. Professions on the whole felt that there was a certain futility to psychiatric care given the paucity of evidence to support practice. This may contribute towards the poor use of hospital care as a therapeutic intervention as part of the wider spectrum of care. Difficulties arise when trying to develop a care pathway with EBP, given the paucity of knowledge on why certain interventions are only partially effective. The development of a care pathway may inform the priorities of the inpatient Acute Care Forum for people diagnosed with schizophrenia. A care pathway should not be constrained, however, to EBP and should incorporate therapeutic activities to improve the overall experience of service users. Limitations on the study and the collection of evidence supporting these conclusions conclude the paper.

Attitude of Health Personnel↗
PubMed2002

The sustained impact of an evidenced-based clinical pathway for acute appendicitis.

Appendicitis is a frequent pediatric surgical condition for which there is great variability among practitioners regarding diagnosis and postoperative management. With this in mind, the authors designed and implemented an evidence-based appendicitis clinical pathway at their institution. Establishment of the pathway resulted in decreased hospital cost, reduced hospital stay, and fewer unnecessary laboratory tests. The purpose of the current study was to determine the sustainability of the pathway beyond its initial implementation phase. The authors showed that several, but not all, favorable outcomes of the pathway were sustained. These data suggest that a clinical pathway for appendicitis at the authors' institution results in sustained beneficial effects in some but not all outcome parameters. Ongoing monitoring of pathway compliance, continued education of practitioners and nursing personnel, and identification of key pathway team member(s) responsible for the pathway system might result in a greater long-term impact of these guidelines.

Appendicitis↗
PubMed1993

Contribution of the pentose phosphate pathway to glucose utilization by preimplantation sheep embryos.

The activity of the pentose phosphate pathway of glucose metabolism in early sheep embryos and in the structures of the advanced conceptus from Day 13 to Day 19 of pregnancy was measured quantitatively during a 2.5-h incubation with glucose as sole energy source. For embryos during cleavage, activity of this pathway accounted for 6-9% of total glucose utilized. The proportion of glucose metabolized through the pentose pathway fell progressively with development and by Day 19 represented 1-2% of glucose turnover. However, total turnover of glucose increased eight fold between the 2-cell and blastocyst stage and the amount of glucose processed through the pentose pathway increased over this time despite the fall in the proportion utilized in this way. In contrast, glucose turnover by the advanced embryo and its extra embryonic membranes progressively decreased as the structures developed. As a result, estimates of the amount of glucose utilized through the pathway per microgram dried weight per hour declined to low values at Day 19 following the peak in activity at about the time of blastulation. Trophoblast and yolk sac processed less glucose through the pentose pathway per microgram dried weight than embryonic tissue but the allantois was similar to the embryo. Overall, the pentose pathway accounted for a relatively constant proportion of the CO2 produced from glucose under these experimental conditions with values generally between 15 and 20% of total CO2 produced. When activities in the components of the advanced conceptus were expressed as the total amount of glucose processed through the pathway per hour, turnover in the embryo, allantois and yolk sac increased progressively with time. By contrast, there was a substantial trough in the activity of the trophoblast on Day 17 of pregnancy.

Allantois↗
PubMed2004

Origin of the classical complement pathway: Lamprey orthologue of mammalian C1q acts as a lectin.

The lectin complement pathway in innate immunity is closely related to the classical complement pathway in adaptive immunity, with respect to the structures and functions of their components. Both pathways are initiated by complexes consisting of collagenous proteins and serine proteases of the mannose-binding lectin (MBL)-associated serine protease (MASP)/C1r/C1s family. It has been speculated that the classical pathway emerged after the lectin pathway, and that the activation mechanism of the latter was partially conserved. The classical and lectin pathways can be traced back to at least cartilaginous fish and ascidian (urochordata), respectively. To elucidate the evolution of the complement system, we isolated and characterized a GlcNAc-binding lectin from sera of lamprey (agnathans), the most primitive vertebrate that lacks the classical pathway. Lamprey GlcNAc-binding lectin was an oligomer consisting of 24-kDa subunits. cDNA and phylogenetic analyses revealed that the lamprey GlcNAc-binding lectin is an orthologue of mammalian C1q, a collagenous subcomponent of the first component involved in binding to immunoglobulins in the classical pathway. Lamprey C1q copurified with MASP-A, a serine protease of the MASP/C1r/C1s family, which exhibited proteolytic activity against lamprey C3. Surface plasmon resonance analysis showed that lamprey C1q specifically bound to GlcNAc, but not various other carbohydrates tested. These results suggest that C1q may have emerged as a lectin and may have functioned as an initial recognition molecule of the complement system in innate immunity before the establishment of adaptive immunity such as immunoglobulins in the cartilaginous fish.

Amino Acid Sequence↗
PubMed2006

Task-modulated "what" and "where" pathways in human auditory cortex.

Human neuroimaging studies suggest that localization and identification of relevant auditory objects are accomplished via parallel parietal-to-lateral-prefrontal "where" and anterior-temporal-to-inferior-frontal "what" pathways, respectively. Using combined hemodynamic (functional MRI) and electromagnetic (magnetoencephalography) measurements, we investigated whether such dual pathways exist already in the human nonprimary auditory cortex, as suggested by animal models, and whether selective attention facilitates sound localization and identification by modulating these pathways in a feature-specific fashion. We found a double dissociation in response adaptation to sound pairs with phonetic vs. spatial sound changes, demonstrating that the human nonprimary auditory cortex indeed processes speech-sound identity and location in parallel anterior "what" (in anterolateral Heschl's gyrus, anterior superior temporal gyrus, and posterior planum polare) and posterior "where" (in planum temporale and posterior superior temporal gyrus) pathways as early as approximately 70-150 ms from stimulus onset. Our data further show that the "where" pathway is activated approximately 30 ms earlier than the "what" pathway, possibly enabling the brain to use top-down spatial information in auditory object perception. Notably, selectively attending to phonetic content modulated response adaptation in the "what" pathway, whereas attending to sound location produced analogous effects in the "where" pathway. This finding suggests that selective-attention effects are feature-specific in the human nonprimary auditory cortex and that they arise from enhanced tuning of receptive fields of task-relevant neuronal populations.

Adaptation, Physiological↗
PubMed2002

Evaluation of a human immunodeficiency virus rule out tuberculosis critical pathway as an intervention to decrease nosocomial transmission of tuberculosis in the inpatient setting.

Nosocomial transmission of Mycobacterium tuberculosis (TB) is a recognized risk in health care settings, and is a particular concern in settings where human immunodeficiency virus (HIV)-infected persons receive care. TB control guidelines have been effective in prevention of nosocomial TB outbreaks and protection of patients and health care workers. In 1993 a South Florida academic medical center noted an increase in TB cases, particularly in HIV-infected persons who had been inpatients. A multidisciplinary team developed an HIV Rule Out TB Critical Pathway as an intervention to deter nosocomial transmission of TB. The pathway was implemented in 1995 on the Special Immunology/Infectious Disease (SI/ID) inpatient unit. This paper describes an evaluation study conducted to determine the effectiveness of the pathway as an intervention to deter nosocomial TB in relation to two areas: (1) early identification of HIV-infected patients with potential TB, followed by immediate placement in respiratory isolation and (2) protection of SI/ID unit personnel from occupational TB exposure. A retrospective review was conducted in June 1999 on the medical records of all patients who had been placed on the HIV Rule Out TB Critical Pathway from 1995-1998. A review was also done of the medical center's confirmed TB cases, and employee health records for tuberculin skin testing (TST) of employees during this time period. The review demonstrated that all HIV-infected patients with confirmed TB had been identified, placed on the pathway and admitted to respiratory isolation at the onset of hospital admission, deterring the potential for a nosocomial TB outbreak. However, in 1998 two SI/ID staff converted from a nonreactive to a reactive TST. Although the pathway was only partially successful in TB protection for staff members, other factors may have caused the TST conversions. A study recommendation is that institutions develop an HIV Rule Out TB Critical Pathway, along with a Rule Out TB Pathway for patients who are not HIV-infected but present with symptoms that may be indicative of TB infection.

AIDS-Related Opportunistic Infections↗
PubMed2004

Functional significance of the pentose phosphate pathway and glutathione reductase in the antioxidant defenses of human sperm.

Glutathione peroxidase is one of the principal antioxidant defense enzymes in human spermatozoa, but it requires oxidized glutathione to be reduced by glutathione reductase using NADPH generated in the pentose phosphate pathway. We investigated whether flux through the pentose phosphate pathway would increase in response to oxidative stress and whether glutathione reductase was required to protect sperm from oxidative damage. Isotopic measurements of the pentose phosphate pathway and glycolytic flux, thiobarbituric acid assay of malondialdehyde for lipid peroxidation, and computer-assisted sperm analysis for sperm motility were assessed in a group of normal, healthy semen donors. Applying moderate oxidative stress to human spermatozoa by adding cumene hydroperoxide, H(2)O(2), or xanthine plus xanthine oxidase or by promoting lipid peroxidation with ascorbate increased flux through the pentose phosphate pathway without changing the glycolytic rate. However, adding higher concentrations of oxidants inhibited both the pentose phosphate pathway and glycolytic flux. At concentrations of 50 microg/ml or greater, the glutathione reductase-inhibitor 1,3-bis-(2-chloroethyl) 1-nitrosourea decreased flux through the pentose phosphate pathway and blocked the response to cumene hydroperoxide. It also increased lipid peroxidation and impaired the survival of motility in sperm incubated under 95% O(2). These data show that the pentose phosphate pathway in human spermatozoa can respond dynamically to oxidative stress and that inhibiting glutathione reductase impairs the ability of sperm to resist lipid peroxidation. We conclude that the glutathione peroxidase-glutathione reductase-pentose phosphate pathway system is functional and provides an effective antioxidant defense in normal human spermatozoa.

Antioxidants↗
PubMed1999

Sevoflurane has no effect on sinoatrial node function or on normal atrioventricular and accessory pathway conduction in Wolff-Parkinson-White syndrome during alfentanil/midazolam anesthesia.

BACKGROUND: The effects of sevoflurane on the electrophysiologic properties of the human heart are unknown. This study evaluated the effects of sevoflurane on the electrophysiologic properties of the normal atrioventricular conduction system, and on the accessory pathways in patients with Wolff-Parkinson-White syndrome, to determine its suitability as an anesthetic agent for patients undergoing ablative procedures. METHODS: Fifteen patients with Wolff-Parkinson-White syndrome undergoing elective radiofrequency catheter ablation were studied. Anesthesia was induced with alfentanil (20-50 microg/kg) and midazolam (0.15 mg/kg), and vecuronium (20 mg) and maintained with alfentanil (0.5 to 2 microg x kg(-1) x min(-1)) and midazolam (1 or 2 mg every 10-15 min, as required). An electrophysiologic study measured the effective refractory period of the right atrium, atrioventricular node, and accessory pathway; the shortest conducted cycle length of the atrioventricular node and accessory pathway during atrial pacing; the effective refractory period of the right ventricle and accessory pathway; and the shortest retrograde conducted cycle length of the accessory pathway during ventricular pacing. Parameters of sinoatrial node function included sinus node recovery time, corrected sinus node recovery time, and sinoatrial conduction time. Intraatrial conduction time and the atrial-His interval were also measured. Characteristics of induced reciprocating tachycardia, including cycle length, atrial-His, His-ventricular, and ventriculoatrial intervals, also were measured. Sevoflurane was administered to achieve an end-tidal concentration of 2% (1 minimum alveolar concentration), and the study measurements were repeated. RESULTS: Sevoflurane had no effect on the electrophysiologic parameters of conduction in the normal atrioventricular conduction system or accessory pathway, or during reciprocating tachycardia. However, sevoflurane caused a statistically significant reduction in the sinoatrial conduction time and atrial-His interval but these changes were not clinically important. All accessory pathways were successfully identified and ablated. CONCLUSIONS: Sevoflurane had no effect on the electrophysiologic nature of the normal atrioventricular or accessory pathway and no clinically important effect on sinoatrial node activity. It is therefore a suitable anesthetic agent for patients undergoing ablative procedures.

Adult↗
PubMed1998

Impact of a clinical pathway for elective infrarenal aortic reconstructions.

OBJECTIVE: To determine the impact of a clinical pathway for elective infrarenal aortic reconstruction on outcome, resource utilization, and cost in a university medical center. SUMMARY BACKGROUND DATA: Clinical pathways have been reported to control costs, reduce resource utilization, and maintain or improve the quality of patient care, although their use during elective aortic reconstructions remains unresolved. METHODS: A clinical pathway was developed for elective infrarenal aortic reconstructions by a multidisciplinary group comprised of representatives from each involved service. The prepathway practice and costs were analyzed and an efficient, cost-effective practice with specific outcome measures was defined. The impact of the pathway was determined by retrospective comparison of outcome, resource utilization, and cost (total and direct variable) between the pathway patients (PATH, n = 45) and a prepathway control group (PRE, n = 20). RESULTS: There were no significant differences in the patient demographics, comorbid conditions, operative indications, or type of reconstruction between the groups. There were no operative deaths and the overall complication rate (PRE, 35% vs. PATH, 34%) was similar. The pathway resulted in significant decreases in the total length of stay and preoperative length of stay and a trend toward a significant decrease (p = 0.08) in the intensive care length of stay for the admission during which the operation was performed. The pathway also resulted in significant decreases in both direct variable and total hospital costs for this admission, as well as a significant decrease in the overall direct variable and total hospital costs for the operative admission and the preoperative evaluation (< or =30 days before operative admission). Despite these reductions, the discharge disposition, 30-day readmissions, and number of postoperative clinic visits within 90 days of discharge were not different. CONCLUSIONS: Implementation of a clinical pathway for elective infrarenal aortic reconstructions dramatically decreased resource utilization and hospital costs without affecting the quality of patient care and did not appear to shift the costs to another setting.

Aged↗
PubMed1998

The effects of clinical pathways for renal transplant on patient outcomes and length of stay.

OBJECTIVES: Clinical pathways have been implemented nationwide but little is understood about their effects on efficiency of care and patient outcomes. The present study examined the effects of both development and implementation of two renal transplant pathways. METHODS: Cohorts of patients at a university hospital were compared before, during, and after the development and implementation of two renal transplant clinical pathways: isolated renal transplant from cadaveric donors (n = 170) or from living donors (n = 178). Clinical pathways for cadaveric and living related donor renal transplants were developed and implemented. Hospital length of stay and complications and infections after renal transplant were determined. RESULTS: Mean length of hospital stay decreased after development and implementation of the cadaveric donor pathway (11.8 days after implementation versus 17.5 days before development). Cadaveric kidney recipients also had statistically fewer complications and infections after both guideline development and guideline implementation (57.1% before, 24.5% during, 18.5% after), but the greatest effect occurred during development. All of these findings persisted after control for demographic and comorbid factors. There were no changes in hospital stay, complications, or infections in the patients who received kidneys from living donors. CONCLUSIONS: The development and use of a clinical pathway for cadaveric donor renal transplant patients was associated with a significant decline in length of stay, complications, and infections, but much of the effect was seen during development rather than during implementation, and a closely related pathway for living related donor patients had no effect. Further understanding of what factors predict an effective pathway and what elements (ie, development or implementation) have an effect should be undertaken.

Adult↗
PubMedDate not supplied

Knowledge-based quality management and clinical pathways.

OBJECTIVES: Although 65% of the hospitals in Taiwan claim to be applying the clinical pathway concept, most hospitals do not implement this concept effectively. The purpose of this study was to determine the reasons for the improper or inappropriate application of the clinical pathway design in hospitals. METHODS: This study differs from other studies in clinical pathway design and application in that it seeks to resolve misunderstandings of the clinical pathway analysis that may have been generated by the responses to survey questionnaires. Therefore, in-depth interviews and Senge's system archetype have been used to ascertain the reasons why the use of a clinical pathway design has been ineffective. We also used the 4 dimensions of knowledge-based management proposed by Drucker to set up the knowledge-based clinical pathway. Thirteen experts used the Delphi method to construct 20 knowledge-based clinical pathway guidelines. CONCLUSIONS: The application of knowledge- and management-based clinical pathway designs is recommended.

Critical Pathways↗
PubMed2003

Effectiveness of the clinical pathway in the management of congestive heart failure.

BACKGROUND: The prevalence of congestive heart failure (CHF) in the United States is approximately 4 million, with associated annual health care expenditures exceeding dollar 8 billion. Clinical pathways for CHF have been developed, but they have not been rigorously evaluated regarding efficacy and improvement in the quality of care. We sought to evaluate the effect of a CHF clinical pathway on hospital charges, length of stay, and use of angiotensin-converting enzyme (ACE) inhibitors in patients with CHF in a retrospective cohort study. METHODS: We studied 371 patients (age range, 44-92 yr) with discharge diagnoses of CHF in a 376-bed community hospital between July 1996 and December 1997. We conducted chart reviews to determine length of stay, hospital charges, and use of ACE inhibitors. RESULTS: Of the 371 patients, 174 were assigned to the clinical pathway and 197 were not. Baseline characteristics of the two groups were similar. The benchmark of less than 4 days' in-hospital stay was achieved in 65% of patients on the pathway and 42% who were not on the pathway (odds ratio, 2.6; 95% confidence interval, 1.67-4.05; P < 0.001). The median hospital charges were lower in the group on the clinical pathway (dollar 3,000 versus dollar 5,500, P < 0.001). In addition, 81% of the patients on the clinical pathway were administered ACE inhibitors, compared with 48% of equally eligible patients from the nonpathway group (odds ratio, 4.68; 95% confidence interval, 2.85-7.72; P < 0.001). CONCLUSION: The clinical pathway for CHF was associated with increased use of ACE inhibitors as well as reduced length of stay and hospital charges.

Adult↗
PubMed2026

Metabolism pathway-based subtyping in pancreatic adenocarcinoma: an integrated study by bulk RNA-sequence and machine learning algorithms.

BACKGROUND: Pancreatic adenocarcinoma (PAAD) is highly aggressive, and its tumor microenvironment has significant metabolic and immune microenvironment complexity and genomic instability. In this study, by integrating the metabolic pathway activity score and clinical data, we constructed a novel risk assessment model to reveal the unique biological behavior and clinical significance behind different PAAD subtypes. METHODS: In this study, the transcriptome and clinical data of TCGA and GSE57495 databases were integrated to explore the interaction between metabolic pathways. Based on unsupervised clustering analysis of pathway activity and survival prognosis, patients with PAAD were classified into metabolic subtypes with significant prognostic differences. Subsequently, we assessed the heterogeneity of these subtypes in terms of clinical outcomes, genomic characteristics, and immune microenvironment composition. Based on the differentially expressed genes (DEGs) among metabolic subtypes, a clinical prognostic risk model and nomogram were constructed, which were double-validated by GSE57495-independent cohort and GSE57495&#xa0;+&#xa0;TCGA-PAAD combined cohort. Finally, the correlations between risk scores (RSs) and signaling pathway activity and tumor immune microenvironment characteristics were evaluated. RESULTS: Based on metabolic pathway correlation and prognostic information, 240 patients in the TCGA-PAAD and GSE57495 datasets were divided into three subgroups. There were significant differences between subgroups in gene expression, pathway activity, clinical prognosis, and immune infiltration characteristics among the subtypes. Using machine learning algorithms, an RS model was constructed from DEGs among the subgroups, with the random forest method showing the best performance. A nomogram integrating the RS and clinical indicators demonstrated excellent predictive accuracy for 1-, 3-, and 5-year survival rates, confirming the RS as an independent prognostic factor. High- and low-risk groups exhibited significant differences in immune infiltration, pathway activity, and gene mutations. Drug sensitivity analysis showed that the high-risk group was more sensitive to AZD6244, ABT737, and other drugs. CONCLUSION: This study stratified patients with PAAD into three subgroups based on metabolic pathways and prognostic information, revealing significant differences in clinical outcomes, immune characteristics, and genetic mutations. The robust RS model developed from these findings demonstrated strong predictive power for patient survival and identified promising therapeutic strategies, providing valuable insights for advancing precision medicine in PAAD.

immune microenvironment↗
PubMed2006

Care pathways in obstetrics: the effectiveness in reducing the incidence of episiotomy in childbirth.

AIM: To develop a care pathway for childbirth. BACKGROUND: Care pathways are emerging as an effective tool to improve clinical and organizational performance. METHODS: A pre- and postimplementation analysis model was used to evaluate the effect of introducing a care pathway for childbirth. Key outcome indicators and costs were reviewed to compare the traditional care processes with those of the care pathway. The study involved 380 women. RESULTS: There was a significant reduction in episiotomy rate (from 14.90% to 8.6%, P = 0.02) in patients being cared for using a care pathway approach; however, there were no differences in caesarean section and in perineal wound rates. The average costs per patient on the care pathway were euro 1278.42 ( pound 873.64) compared with euro 1,146.87 ( pound 783.74) preimplementation. The study also demon- strated an increase in patient satisfaction for women cared for using the care pathway approach. CONCLUSIONS: The care pathway proved to be a valid methodological approach to childbirth, allowing healthcare workers to efficiently share the care of the women, guaranteeing safe and effective care.

Adult↗
PubMed2006

Bandwidth determines modulatory effects of centrifugal pathways on cochlear hearing desensitization caused by loud sound.

Centrifugal olivocochlear (OC) pathways modulate cochlear hearing losses induced in cats by loud sounds varying in bandwidth from tones to clicks and noise bands, in a variety of conditions. The general effect, always to reduce hearing damage, can be a net effect resulting from complex interactions between OC subcomponents (crossed and uncrossed OC pathways). The interactions between these subcomponents vary with type of loud sound, suggesting that sound bandwidth may be important in determining how OC pathways modulate loud sound-induced hearing loss. This dependency was examined and here it is reported that OC pathways do not alter cochlear hearing losses caused by loud noise with a 2-kHz-wide bandwidth intermediate between the loud sounds of previous studies. Increasing stimulus bandwidth even slightly more, to use a loud 3.5-kHz-wide bandwidth noise as the damaging sound, once again revealed OC modulation of cochlear hearing loss. The fact that OC pathways do not modulate cochlear hearing losses induced by loud 2-kHz-wide noise was demonstrated in three very different test conditions in which OC pathways modulate hearing losses caused by narrower or broader bandwidth sounds. This confirmed that the absence of centrifugal modulation of hearing loss to this particular sound was a robust phenomenon not related to test condition. The absence of overall centrifugal effects was also true at the level of subcomponent pathways; neither crossed nor uncrossed OC pathways individually modulated cochlear hearing losses to the loud 2-kHz-wide noise. This surprising frequency dependency has general implications for centrifugal modulation of cochlear responses.

Acoustic Stimulation↗
PubMed1994

Radiofrequency catheter ablation of an atriofascicular pathway during atrial fibrillation: a case report.

INTRODUCTION: A male patient with an atriofascicular pathway underwent catheter ablation of the atriofascicular pathway during atrial fibrillation. METHODS AND RESULTS: The patient had preexcited atrial fibrillation both clinically and repeatedly during electrophysiologic study. A preexcited tachycardia with a 1:1 AV relationship and regular RR intervals was also induced. Catheter ablation of the atriofascicular pathway could only be performed during persistent atrial fibrillation, based on mapping of the pathway's insertion into the right bundle branch. Following successful ablation and cardioversion to sinus rhythm, a regular QRS tachycardia (atrioventricular [AV] nodal reentry) having the same rate, atrial activation sequence, and His-atrial time as the regular preexcited tachycardia noted preablation was initiated. An AV nodal slow pathway modification eliminated this tachycardia. Neither atrial fibrillation nor AV nodal reentry has recurred on follow-up. CONCLUSION: This is the first report of atriofascicular mapping and ablation performed exclusively during atrial fibrillation and illustrates the utility of mapping the pathway's ventricular insertion. Other unusual features ("bystander" pathway activation during AV nodal reentry, possible role of the pathway in genesis of atrial fibrillation) are discussed.

Adolescent↗