Familial amyloidosis with polyneuropathy (FAP) is a neuropathic form of heredofamilial systemic amyloidosis. Clusters of patients have been reported predominantly from Portugal, Japan and Sweden. The present study examines the involvement of the heart in individuals with the Swedish variety of FAP. During long-term ECG recording in 16 patients, a high frequency of disturbances of sinus node function and atrioventricular conduction were observed. Long-term ECG may help considerably in the evaluation of symptoms attributable to disturbances of heart rhythm in FAP. A retrospective survey of 20 patients with FAP treated with a pacemaker showed that the indication for pacing was advanced atrioventricular block (12 cases), dysfunction of the sinus node (5 cases), and atrial fibrillation with a slow ventricular response (3 cases). All patients experienced the effective relief of symptoms attributable to a slow ventricular rate. The long-term prognosis, however, seemed unaffected by this treatment. Histopathological examination of the sinoatrial (9 cases) and atrioventricular (6 cases) parts of the conduction system showed marked amyloid infiltration in all cases, which may explain the high occurrence of disturbances of cardiac rhythm and conduction. Twelve patients were examined by two-dimensional echocardiography and changes of varying degrees, such as highly refractile myocardial echoes (12 cases) and thickened ventricular walls (8 cases) and valves (7 cases), could be observed. Technetium-99m-pyrophosphate scintigraphy of the same patients revealed abnormal myocardial uptake of the isotope only in four. Echocardiography thus seems to be superior to scintigraphy for non-invasive detection of cardiac involvement in FAP. Myocardial samples from regions producing highly refractile myocardial echoes were obtained at in vitro échocardiographie examination of hearts from FAP autopsy cases. Histological examination showed that the highly refractile echoes corresponded to more or less sharply delineated nodules, containing amyloid and collagen in various amounts. / digitalisering@umu

BACKGROUND: His bundle pacing (HBP) is a relatively new treatment modality for patients experiencing issues with the cardiac conduction system. The treatment is thought to be an advantageous therapy compared with the standard treatment because it uses the native conduction pathway instead of introducing a non-physiological correction pathway which has been documented to increase the risk of heart failure. First carried out in humans in 2000 (Deshmukh, Casavant, Romanyshyn, & Anderson, 2000), HBP has been shown to be superior to right ventricular pacing and equivalent to cardiac resynchronization therapy. Because of the relative recency of the application of this technique in humans, there is a need for more studies to understand the long-term effectiveness and to guide training for new clinicians. 
OBJECTIVES: The objectives of this study were to (1) define the utility of three-dimensional mapping as a guiding tool for lead placement in HBP, (2) investigate the electroanatomical imaging of the atrioventricular (AV) septum, bundle of His, and other areas of the conduction system, (3) apply these observations to guide optimal pacing lead placement in the clinical setting, and (4) describe the correction of right and left bundle branch blocks by HBP. METHODS: Patients with pacemaker indication due to diseased conduction system were identified and recommended to undergo His bundle lead implantation. The lead was navigated into the heart by fluoroscopy and progressing the catheter through the axillary, subclavian, and cephalic veins. During the procedure, electroanatomical mapping was conducted by a quadripolar catheter to guide lead placement. His cloud, non-selective capture, and selective capture areas were marked and used to generate a 3D model layering the patient conduction system onto the physical anatomy. Pacemapping was then utilized to identify the most suitable area for disease correction.
Results: HBP mapping data were available in 24 patients. Several different responses to pacemapping were observed in the area of the AV septum including selective HBP (S-HBP), non-selective HBP (NS-HBP) (with upper, lower, and common variants), and right bundle branch (RBB) capture. Capture areas were superimposed onto the 3D model in real time and used to guide lead implantation for purposes of correcting various forms of conduction disease. The use of electroanatomical mapping (EAM) reduced the need for fluoroscopic guidance compared with the non-EAM-assisted procedure. Four common patterns were observed while mapping: (1) pattern 1, selective capture surrounded by upper and lower non-selective regions of capture; (2) pattern 2, selective capture surrounded by a common non-selective region of capture; (3) pattern 3, two separate non-selective capture areas with no selective capture; (4) pattern 4, common non-selective capture area with no selective capture. There was no correlation between capture threshold voltage and location of non-selective capture. Also, no correlation was found between capture threshold voltage and presence of common non-selective versus upper and lower non-selective capture areas. Patients with left bundle branch block (LBBB) and RBBB had similar His capture anatomy and were correctable by NS-HBP. CONCLUSIONS: HBP guided by electroanatomical mapping should be considered as a standard approach during pacemaker implantation. Because the underlying conduction anatomy is variable among patients, the use of EAM can direct lead positioning at a more physiologic location. In addition, EAM-guided implantation can reduce the need for fluoroscopy.

No description available.

Spatio-temporal variation in action intervals during ventricular fibrillation (VF) suggestthat the excitable gap may also be distributed spatio-temporally. The observation leadus to hypothesize that distributed pacing can be used to modify and entrain electricalactivation during VF. We tested this hypothesis using simulated VF and animal studies. We simulated VF in a 400 by 400 cell matrix. Simulation results showed that activationpattern could be entrained using spatially distributed stimulation. Up to a certain limit,increasing stimulus strength and density led to improved entrainment. Best entrainmentwas obtained by pacing at a cycle length similar to the intrinsic cycle length. In order to verify whether activation could be entrained experimentally, eight opticallyisolated biphasic TTL addressable stimulators were fabricated. Distributed stimulationwas tested during electrically induced VF in two canines and two swine. Resultsshowed that electrical activation could be entrained in both species. Similar to that insimulation, better entrainment was obtained with denser pacing distribution and atpacing cycle length similar to the intrinsic cycle length. As expected, entrainment wasaffected by tissue thickness. Our results show that spatio-temporally distributed pacingstrength stimuli can be used to modify activation patterns during VF.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2006. / Description based on information viewed Oct. 3, 2006; title from title screen. Includes bibliographical references (p. 87-90).

Frågeställningen till den här studien undersöker hur spelare upplever agency i ett förgrenande dialogsystem med tidsbegränsade valtillfällen i jämförelse med dialogsystem utan tidsbegränsningar. I bakgrunden observeras vad agency betyder och hur begreppet används samt vad tidigare studier har lett till. Kapitlet fortsätter med att diskutera vad meningsfulla val är för något och hur en berättelse kan upplevas som trovärdig. För att kunna besvara studiens frågeställning skapades två olika textbaserade spel, en med tidsbegränsningar i dialogerna och en utan. För övrigt har de inga andra skillnader. Dessa användes sedan till att mäta skillnader i hur spelarna upplevde agency genom att jämföra resultatet från två olika undersökningsgrupper, en för varje version av spelet. Resultatet bestod av ett antal åsikter från deltagarna angående sin spelupplevelse. Skillnaderna mellan grupperna var små och mängden insamlad data var för liten för att ge något säkert resultat och frågan fick inte något pålitligt svar.

Introduction: Activity pacing is often advised as a coping strategy for managing chronic conditions (such as chronic low back pain, chronic widespread pain and chronic fatigue syndrome/myalgic encephalomyelitis). Despite anecdotal support for activity pacing, there is limited and conflicting research evidence regarding the efficacy of this strategy. Pacing has not been clearly operationalised, and existing descriptions are diverse and include strategies that encourage both increasing and decreasing activities. Moreover, there are few validated scales to measure activity pacing. Aim: To develop an activity pacing questionnaire (APQ) for adult patients with chronic pain and/or fatigue, and to determine its psychometric properties and acceptability. Methods: The study had a three stage mixed method design. Stage I, the Delphi technique involved a three-round consensus method to develop the initial items of the APQ using an expert panel of patients and clinicians. Stage II, the psychometric study, implemented a cross-sectional questionnaire design study, involving a large sample of patients with chronic conditions. This stage assessed the underlying pacing themes of the APQ using factor analysis, internal and test-retest reliability using Cronbach’s alpha and intraclass correlations (ICCs); and validity using correlations with validated measures of pain, fatigue, anxiety, depression, avoidance, and mental and physical function. Stage III, the acceptability study, explored patients’ opinions of the APQ, together with the concept of activity pacing via telephone interviews. The qualitative interview data were analysed using framework analysis. Results: Forty-two participants completed Stage I, the Delphi technique (4 patients, 3 nurses, 26 physiotherapists and 9 occupational therapists). The resulting APQ contained 38 questions involving a number of different facets, including breaking down tasks, gradually increasing activities and setting goals. Stage II, the psychometric study, was completed by 311 patients, of whom 69 were involved in a test-retest analysis. Following factor analysis, eight items were removed from the APQ. Five themes of pacing were identified in the 30-item APQ: Activity limitation, Activity planning, Activity progression, Activity consistency and Activity acceptance. These demonstrated satisfactory internal consistency, test-retest reliability, and construct validity against validated measures. Activity limitation, Activity planning, Activity progression and Activity acceptance correlated with worse symptoms, and Activity consistency correlated with improved symptoms. Sixteen patients participated in Stage III, the acceptability interviews. The APQ was found to be generally acceptable. Four activity behaviour typologies emerged through the interviews: Task avoidance, Task persistence, Task fluctuation (boom-bust) and Task modification (activity pacing).Conclusion: This is the first known study that has engaged both patients and clinicians in the development of an activity pacing questionnaire. Developed to be widely used across a heterogeneous group of patients with chronic pain and/or fatigue, the APQ is multifaceted, comprehensive and contains more themes of pacing than existing pacing subscales.

Micro-Images for Solo Flute, Genera for Flute/Alto Flute/Bass Flute and Clarinet/Bass Clarinet, and Poème exotique for Flute and Piano by American composer Daniel Kessner (b. 1946) utilize a hybrid compositional approach in which microtones are incorporated with more traditional chromatic writing. Through representative musical examples from each piece, this document highlights the timbral, dynamic and pacing complexities associated with the microtonal fingerings and prompts flutists to forgo idiosyncratic tendencies in favor of contextually based choices. In order to help guide musicians toward effective performances of these three pieces and similar works, a new tone color spectrum and description of relative dynamics are provided along with a discussion of the relationships between tone colors, relative dynamics and temporal pacing. Appendices include transcripts of email interviews with composer Daniel Kessner and Carla Rees, British contemporary flutist, as well as an updated list of Kessner’s flute works.

Heart disease is the leading cause of death in the world. Finding future therapeutics for heart disease requires the development of mature 3D engineered human cardiac tissues that can serve as reliable models for biological studies and drug development. The ability to measure and stimulate cardiac action potentials (APs) is key to the development of these 3D tissue models. Optical measurement and stimulation methods offer an enticing solution to longstanding tissue development testbed needs. However, existing optical measurement methods have relied on toxic voltage dyes and motion inhibiting drugs, and existing optical stimulation methods have mainly focused on optogenetic modification techniques. In this dissertation, I present two related optical systems built for 3D engineered human cardiac microtissues, organized into two chapters: 1) a dual-mode voltage and contraction imaging optical microscope for tracking action potential metrics with fluorescent genetically encoded voltage indicator Archon1, and 2) an all optical cardiac stimulation system for unmodified engineered human cardiac micro-tissues with red and blue laser pulse options. These systems offer cardiac researchers less invasive optical solutions for cardiac action potential visualization and pacing: the microscope system allows direct action potential measurements without the use of toxic dyes, and the stimulation system allows ex-vivo pacing without any modification to the sample, genetic or otherwise. I will discuss the system design motivations, challenges, results, and mechanisms of this work.

Optical packet switching networks are the foundation for next generation high speed Internet and are fast becoming the norm rather than an option. When such high speed optical networks are taken into account, one of the key considerations is packet buffering. The importance of packet buffering plays an even bigger role in optical networks because of the physical and technological constraints on the buffer sizes that can be implemented. Existing protocols, in many real world scenarios do not perform well in such networks. To eliminate such scenarios where there is a high possibility of packet loss, we use packet pacing. The proposed pacing scheme aims to reduce or eliminate packet losses arising from packet bursts in small-buffer networks. This thesis deals with a proposed hardware design and implementation of the packet pacing system on a NetFPGA. Our results show that the packet pacer can be implemented with a low overhead on hardware resources.