Activity Controlled Cardiac Pacemakers During Stairwalking: A Comparison of Accelerometer with Vibration Guided Devices and with Sinus Rate

Activity controlled pacemakers are the most widely used rate adaptive systems. We studied second-generation activity controlled systems (accelerometer) in 21 patients with such an accelerometer controlled system implanted during walking level and stairs. We compared them to the rate of vibration controlled, first-generation activity pacemakers and to the sinus rate of a healthy control group. A metronome directed the speed during walking and climbing stairs at 92, 108, and 120 steps/min. At 92 steps/min, the new accelerometer controlled systems showed a significant (P ≤ 0.001) pacing rate increase from 107 ± 8 beats/mm during walking level to 124 ± 8 beats/min during climbing stairs, and a significant decrease to 105 ± 12 beats/mm during walking downstairs. In contrast, first-generation activity controlled pacemakers showed a less physiological rate behavior with higher pacing rate (113 ± 7 beats/min) walking downstairs than walking upstairs (97 ± 9), For everyday activities at normal walking speed, accelerometer controlled pacemakers show a more physiological rate behavior than first-generation pacemakers, hut they lose this physiological response with faster walking.     

A Comparative Study of Activity and Dual Sensor: Activity and Minute Ventilation Pacing Responses to Ascending and Descending Stairs

Previous studies with activity-based rate; adaptive pacemakers have shown a somewhat paradoxical response when comparing ascending stairs to descending stairs. The objective of this investigation was to measure dual-sensor rate response provided by activity and minute ventilation (MV) compared with activity alone, and with a control group, during ascending and descending stairs. For dual sensor mode, measured mean peak pacing rate with 72 (92) steps per minute was 111 ± 13 beats/min (124 ± 14 beats/min) ascending stairs and 81 ± 7 beats/mm (97 ± 13 beats/min) for descending. For activity mode alone, mean peak pacing rate was 90 ± 12 beats/min (108 ± 19 beats/min) ascending stairs and 97 ± 12 beats/min (123 ±17 beats/min) descending. The mean peak control group heart rate ascending stairs for a step rate of 72 (92J steps/min were 116 ± 11 beats/min (127 ±14 beats/min) ascending stairs and for descending 89 ± 12 beats/min (95 ± 11 beats/min). While for dual sensor controlled pacing there was a significant difference for ascending and descending stairs at both step rates, there was no difference between going upstairs and downstairs for activity mode alone. Rates with dual sensor did not significantly differ from respective rates of the control group. The mean correlation coefficient between MV and paced rate was 0.85. Pacing heart rates delivered by the dual sensor mode were appropriate for ascending and descending stairs. In contrast to activity mode alone, the peak heart rates for dual sensor mode are higher during ascending than during descending stairs.     

Strong CD4 Th1 responses to HIV and hepatitis C virus in HIV-infected long-term non-progressors co-infected with hepatitis C virus

OBJECTIVES: To compare the T-cell responses to hepatitis C virus (HCV) and HIV in HIV-infected long-term non-progressors (LT-NP) and HIV-positive progressors co-infected with HCV and in HIV-negative HCV-infected patients. METHODS: Three groups were studied: 10 HCV/HIV-infected LT-NP, 26 HCV/HIV-infected progressors and 13 HCV-infected/HIV-negative patients. Virus-specific CD4 and CD8 T-cell responses in peripheral blood were assessed by interferon (IFN)-gamma Elispot assays using recombinant proteins (HIV-p24 and three HCV antigens) and 16 HIV or HCV HLA A3- and/or HLA A2-restricted cytotoxic T lymphocytes peptides. Statistical analysis was performed with non-parametric tests. RESULTS: In addition to high T helper 1 (Th1) cell frequencies directed against HIV-p24, LT-NP had significantly (P < 0.05) higher frequencies of Th1 cells against HCV than the two other groups. No difference was observed between HIV-infected progressors and HIV-negative controls. Furthermore, HCV-specific CD4 and CD8 T cells were correlated in LT-NP (P = 0.006). CONCLUSION: Thus, independently of the HIV-related immune alterations, LT-NP of the HIV-infection might have an intrinsic capacity to develop strong Th1 cell responses to viruses, particularly HIV and HCV.     

Regulation of Pacing Rate by Variations of Mixed Venous Oxygen Saturation

La saturation d'oxygene du sang du ventricule droit (So₂) serait un capteur idéal pour asservir la fréquence d'un stimulateur implanté. Afin de prouver cette hypothèse, des inesures de So₂ au repos et à l'éxercice ont été réalisées chez des sujets normaux et chez des patients porteurs de stimulateurs; ensuite un algorithme a été développé pour faire varier la fréquence de stimulation en fonction de la So₂ mesurée. Les résultats suggèrent que cette méthode pourrait être utile aux implants à long terme.     

An Active Optical Sensor for Monitoring Mixed Venous Oxygen-Saturation for an Implantable Rate-Regulating Pacing System

Les stimuJateurs dits "physiologiques" qui sont actuellement disponibles ne restaurent pos la fréquence optimale dans les cos de défaillance auriculaire. Ďautres paramètres biologiques doivent servir de stimulus physiologique pour determiner ľouto-reglage de la fréquence. La saturation veineuse mesurée par capteur optique serait probablement le paramètre idéal pour ce système de sfimulation. Des recherches supplémentaires sont nécessaires pour bien déterminer les modalités des reponse du système.
Presently available physiologic pacing systems do not fully restore rate regulation, especially in respect to little or no atrial response to activity. Other biologic parameters, detected by sensors, may provide the physiologic responsiveness necessary to rate-regulating pacemakers. An optical sensor using mixed venous oxygen saturation may be the ideal parameter for such a pacing system. At present, further research is necessary to elaborate a suitable algorithm for optimal rate control.     

IMPLEMENTATION OF EVIDENCE-BASED ASSESSMENT OF UPPER EXTREMITY IN STROKE REHABILITATION: FROM EVIDENCE TO CLINICAL PRACTICE

ObjectiveThere is an evidence–practice gap in assessment of the upper extremities during acute and subacute stroke rehabilitation. The aim of this study was to target this gap by describing and evaluating the implementation of, and adherence to, an evidence-based clinical practice guideline for occupational therapists and physiotherapists.MethodsThe upper extremity assessment implementation process at Sahlgrenska University Hospital comprised 5 stages: mapping clinical practice, identifying evidence-based outcome measures, development of a guideline, implementation, and evaluation. A systematic theoretical framework was used to guide and facilitate the implementation process. A survey, answered by 44 clinicians (23 physiotherapists and 21 occupational therapists), was used for evaluation.ResultsThe guideline includes 6 primary standardized assessments (Shoulder Abduction, Finger Extension (SAFE), 2 items of the Actions Research Arm Test (ARAT-2), Fugl-Meyer Assessment of Upper Extremity (FMA-UE), Box and Block Test (BBT), 9-Hole Peg Test (9HPT), and grip strength (Jamar hand dynamometer)) performed at specified time-points post-stroke. More than 80% (35 to 42) clinicians reported reported being content with the guideline and the implementation process. Approximately 60–90% of the clinicians reported good adherence to specific assessments, and approximately 50% reported good adherence to the agreed time-points. Comprehensive scales were more difficult to implement compared with the shorter screening scales. High levels of work rotation among staff, and the need to prioritize other assessments during the first week after stroke, hindered to implementation.ConclusionThe robustness of evidence, adequate support and receptive context facilitated the implementation process. The guideline enables a more structured, knowledge-based and consistent assessment, and thereby supports clinical decision-making and patient involvement.LAY ABSTRACTCurrently available clinical practice guidelines do not specify which outcome measures should be used at which time-points for people after stroke. This study describes the implementation process and evaluation of a clinical practice guideline developed for the assessment of upper extremity function after stroke. The guideline is based on recent research evidence and defines the assessments, and the time-points at which the assessments should be performed. An evaluation survey showed that clinicians valued the clear structure of the guideline and found it useful for prognosis and treatment planning. Robust evidence, and active involvement of clinicians and leaders, were important elements of implementation. The guideline will potentially improve the quality of rehabilitation through increased knowledge of prognosis and treatment effects, based on the assessment of arm function in people with stroke, thereby enabling a more evidence-based, consistent, and individually tailored rehabilitation.Key words: clinical practice guideline, evidence-based practice, implementation science, stroke, rehabilitation, knowledge translation, upper extremity, assessment

Considerable efforts have been made recently in the field of stroke rehabilitation to develop evidence-based agreed guidelines for upper extremity assessment (1–4). Advances in predicting stroke outcomes, in terms of motor function and activity, have been the primary driver of this development (5–7). There is, however, a clear evidence–practice gap, since the use of recommended upper extremity outcome measures in day-to-day clinical practice is sparse. It is well recognized that valid, reliable and responsive outcome measures, performed at pre-defined time-points after stroke, are required for effective rehabilitation (2–4). Currently available clinical guidelines recommend the use of standardized outcome measures, but often do not specify what outcome measures should be used, at what frequency, or in what settings (2).The implementation of standardized recommended upper extremity outcome measures in clinical routine practice takes time and effort. Increased and consistent use of such measures is, however, required to enable person-centred informed clinical decision-making throughout the rehabilitation pathway, and thereby improve patient outcomes. Overall adherence to stroke guidelines varies, but, in general, it is greater when the implementation process includes systematic and well-defined activities (8–10). There are no recognized “gold standard” implementation activities, although multifaceted interventions involving educational outreach and a structured theoretical approach have been suggested to work best (8, 9). Organizational and multidisciplinary team factors, staff beliefs regarding the guidelines, integration of patient-centred recommendations into practice, awareness of guidelines, changing routines, and necessary time investment, are known factors affecting adherence (8, 10).The successful implementation of evidence into practice is dependent on the quality of evidence, the context, and how the evidence is introduced into practice (facilitators) (11). These 3 key elements, being part of the Promoting Action on Research Implementation in Health Services (PARIHS) theoretical framework, have been employed widely in different implementation activities (11, 12). This theoretical model prerequisites that the evidence is robust, practitioners agree with it, and the context is receptive, including the formal leaders, and that appropriate facilitation is ensured (11, 13). The Knowledge to Action (KTA) framework is another theoretical tool that has been widely used to make the process of knowledge translation into practice more systematic (14). The KTA emphasizes the importance of adapting knowledge to the local context, of involving stakeholders, and of being aware of barriers, facilitators and user needs (14).The literature is extensive regarding the implementation of stroke guidelines into clinical practice (8, 9), but only a few studies have specifically targeted assessment and use of standardized outcome measures (15, 16). More recent work on recommendations regarding upper extremity outcome measures (3) also imply a need to move this research evidence into stroke rehabilitation practice.The aim of this study was to describe and evaluate the implementation process and adherence to an evidence-based clinical practice guideline (CPG) for physical therapists (PT) and occupational therapists (OT) in the assessment of upper extremity function and activity during acute and subacute stroke rehabilitation.