It is a known problem that a Spinal Cord Stimulator (SCS) can interact with an Implantable Cardioverter Defibrillator (ICD) when both devices are implanted in the same patient. Interactions between the SCS and ICD can cause inappropriate therapy which can be harmful to the patient. While ICD devices have a distinct narrowband sensing bandwidth, the pulse configurations that current SCS devices deliver were not designed with this frequency region in mind. In this thesis, I recommend a new pulse configuration for SCS devices that will minimize the interaction between the two devices. I produce a theoretical equation for each pulse configuration in the frequency domain using the Laplace transform and present the results in Matlab. I also design my own SCS device to deliver multiple pulse configurations and use it to gather empirical data. The theoretical and empirical results are used to show the extent of the improvement between the new pulse and existing pulse configurations. The results prove that the new pulse configuration will significantly reduce crosstalk within the desired ICD bandwidth. A reduction in crosstalk will decrease the probability that an SCS will interact with a ICD device.

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<p><strong>Background:</strong> Heart failure (HF) constitutes an important growing medical and economic problem with high prevalence and mortality. Prognosis assessment remains a challenge because of the dynamic nature of HF and the existence of some unexplained variation in outcomes. Our objective was to refine the process of prognostic assessment in current HF patients.</p> <p><strong>Methods:</strong> We conducted a systematic review to identify existing risk prediction models in ambulatory HF patients, a meta-analysis to identify mortality predictors in HF patients treated with an implantable cardioverter defibrillator (ICD), a retrospective cohort study to validate a new model, the HF Meta-Score, derived from the results of the meta-analysis and a cross-sectional and prospective cohort study to evaluate whether circulating progenitor cells (CPCs) are associated with functional capacity and mortality in ambulatory HF patients.</p> <p><strong>Results:</strong> We identified 20 risk prediction models in ambulatory HF patients; only five were externally validated showing limited discrimination and calibration. The two most validated models were derived from HF cohorts from the 1990s and reported limited performance in ICD patients. In a meta-analysis, we identified that age, baseline renal function, history of heart failure, chronic obstructive pulmonary disease, diabetes, peripheral vascular disease, left ventricular ejection fraction, NYHA class, atrial fibrillation, wide QRS and the occurrence of appropriate or inappropriate ICD shocks were independent mortality predictors. Some of these predictors were omitted in previously identified models. From the results of the meta-analysis, we developed the HF Meta-Score that showed better performance that an existing model. We observed that CPCs were independently associated with functional capacity and outcomes in ambulatory HF patients.</p> <p><strong>Conclusions:</strong> These results open many pathways to further refine the prognostic assessment in ambulatory HF patients. The HF Meta-Score is a promising score. The clinical utility of the HF Meta-Score and of the incorporation of new predictive factors, such as CPCs, needs to be tested.</p> / Doctor of Philosophy (PhD)

Abstrakt Bakgrund: Användning av i implanterbar kardioverter-defibrillator (ICD) och pacemaker ökar i samhället då fler överlever hjärtkomplikationer. Många av dessa patienter överlever genom att patienten har fått en pacemaker eller ICD implanterad. Samtidigt som implanterbar kardioverter-defibrillator ökar så ökar även MR-undersökningarna i samhället. MR - modaliteten är en undersökning som inte ger patienter joniserande strålning samt ger denna modalitet bättre bildkvalité på människans mjukvävnader till jämförelse med en DTundersökning. MR - undersökningarna har blivit en populär metod att diagnostisera patienter och även patienter med pacemaker eller ICD. Trots detta har externa magnetfältet påverkat pacemakern och ICD till den grad att patienter har avlidit. Syftet: Syfte med studien är att belysa befintlig kunskap om säkerhetsrutiner och risker vid MR-undersökningar av patienter som har pacemaker eller implanterbar kardioverter-defibrillator. Metod: Studien genomfördes som en allmän litteraturöversikt. Artikelsökningar gjordes i databaserna Pubmed och Cinahl. Tolv kvantitativa artiklar valdes som sedan granskades och analyserades för att svara mot syftet. Resultat: Säkerhetsrutiner och risker kring pacemaker och ICD sammanställdes i två huvudkategorier vilka är säkerhetsrutiner och risker. Slutsats: I röntgensjuksköterskans yrkesroll är det viktigt att följa det lokala säkerhetsrutiner såsom att följa sjukhusets protokoll och att ha bra kommunikation med patienter med pacemaker eller ICD för att följa upp så patienten inte får några symtom under eller efter undersökningen. Genom att följa dessa säkerhetsrutiner förebygger vårdpersonalen symtom hos patienter och riskerna minimeras. / Abstract Introduction: The use of implanted cardiovascular devices such as pacemaker and ICD is increasing in society as more people survive cardiac complications. Many of these patients survive by having a pacemaker or ICD implant. While implanted cardiovascular devices are increasing, so are MRI scans in society. MRI is an examination that does not give patients ionizing radiation and provides better image quality of human soft tissues compared to CT scan. MRI scans have become a popular method of diagnosing patients and also patients with pacemaker or ICD. Despite this the external magnetic field affects the pacemaker and ICD to the point where patients have died. Aim:The purpose of the study is to shed light on existing knowledge about safety routines and risks in MRI examinations of patients who have a pacemaker or implantable cardioverter-defibrillator. Method: The study was conducted as a general literature overview. Article searches were made in the Pubmed and Cinahl databases. Twelve quantitative articles were selected which were then reviewed and analysed to meet the purpose. Results: Safety routines and risks around pacemaker and ICD were compiled into two main categories, which are safety routines and risks. Conclusion: In the professional role of the radiographer, it is important to follow local safety procedures such as following hospital protocols, monitoring and also having good communication with patients who have pacemaker or ICD during and after examinations so the patient does not experience any symptoms. By following these safety procedures the healthcare professionals will minimize the risks and symptoms in patients with cardiovascular implantable during and after MRI scan.

Varje år drabbas 10 000 människor av plötsligt hjärtstopp utanför sjukhus. De personer som överlever ett hjärtstopp kan bli aktuella för behandling med en Implanterbar Defibrillator (ICD).  Denna har funnits i bruk sedan 1980. Antalet implantationer ökar och utvecklingen går ständigt framåt. Sjukvården har en viktig roll i att stödja, utbilda och informera patienter och deras anhöriga så att de kan anpassa sig till det nya livet som ICD bärare. Syftet var att belysa ICD-bärares upplevelser av förändrad livssituation. Detta gjordes genom en litteraturstudie. Resultatet bygger på analys av åtta kvalitativa och tio kvantitativa vetenskapliga artiklar. Patienter med ICD upplever psykisk påfrestning, ett beroende av andra människor, att tvingas till levnadsförändringar samt acceptens till det nya livet som ICD-bärare. Implantation av en ICD innebär för många människor att få en ny chans till livet men det innebär också fysiska, psykiska och sociala omställningar i det vardagliga livet. Dessa omställningar påverkar också nära anhöriga. Eftersom antalet ICD implantationer ständigt ökar och det har visat sig att livssituationen på olika sätt förändras är det viktigt att omvårdnaden av denna patientgrupp präglas av individuellt stöd och utbildning i kombination av gott tekniskt kunnande för att underlätta anpassningen till livet som ICD-bärare. / Every year, there are 10 000 cases of sudden cardiac arrest outside of hospitals. Those who survive a cardiac arrest may be considered for treatment with an Implantable Cardioverter Defibrillator (ICD). The ICD has been in use since 1980 and the developments along with the number of implantations are continuously evolving. The health care system has an important role in supporting, educating and informing the patients and their families, to help them adapt to the new life as or with an ICD-bearer. The purpose of this study is to highlight the experiences and life alterations the ICD-bearer faces. The results are based on the analysis of eight qualitative and ten quantitative research articles. Patients with ICDs experience psychological distress; a dependence on other people; being forced to make life alterations and finding acceptance for the new life as an ICD-bearer. For many, an ICD is equivalent to a new chance at life, but it also represents every day physical, psychological and social changes. Changes that also affect close relatives. The care of these patients ought to be characterized by individual support and education, as the number of ICD implantations is constantly increasing and since it has been proven that life situations change. This in combination with good technical expertise facilitates the adaptation to life as an ICD-bearer.

Depuis le début des années 2000, le défibrillateur automatique implantable (DAI) est prescrit de manière prophylactique aux populations à risque de mort subite. Nombre de ces implantations semblent prématurées, ce qui pose problème en raison des complications post-opératoires encourues. Il apparaît donc important de mieux définir la population à risque de mort subite, afin d'optimiser la sélection des patients.Le pouvoir prédictif de mort subite des différents descripteurs du Holter a fait l'objet de nombreuses études univariées, sans permettre d'amélioration des critères de sélection. Dans ce mémoire, nous présentons l'analyse multivariée des descripteurs du Holter que nous avons menée. Nous avons extrait l'ensemble des descripteurs calculables sur la base étiquetée d'enregistrements de patients, victimes ou non d'arythmies traitées par le DAI, dont nous disposons. À l'aide de connaissances physiologiques sur l'arythmogenèse, nous avons réalisé une sélection des descripteurs les plus pertinents. Puis, par une méthode originale de conception et d'évaluation de classifieur, nous avons construit un classifieur ad hoc, basé, sur les connaissances physiologiques de l'arythmogenèse ; ce classifieur discrimine les patients à risque, des patients pour lesquels l'implantation ne paraît pas opportune.Au vu des performances atteintes, il semble possible d'améliorer la fiabilité des indications d'implantation prophylactique, à l'aide de méthodes d'apprentissage statistique. Pour valider cette conclusion, il paraît néanmoins nécessaire d'appliquer la méthode exposée dans la présente étude à une base de données de plus grande dimension, et de contenu mieux adapté à nos objectifs. / Implantable cardioverter defibrillators (ICD) have been prescribed for prophylaxis since the early 2000?s, for patients at high risk of SCD. Unfortunately, most implantations to date appear unnecessary. This result raises an important issue because of the perioperative and postoperative risks. Thus, it is important to improve the selection of the candidates to ICD implantation in primary prevention. Risk stratification for SCD based on Holter recordings has been extensively performed in the past, without resulting in a significant improvement of the selection of candidates to ICD implantation. The present report describes a nonlinear multivariate analysis of Holter recording indices. We computed all the descriptors available in the Holter recordings present in our database. The latter consisted of labelled Holter recordings of patients equipped with an ICD in primary prevention, a fraction of these patients received at least one appropriate therapy from their ICD during a 6-month follow-up. Based on physiological knowledge on arrhythmogenesis, feature selection was performed, and an innovative procedure of classifier design and evaluation was proposed. The classifier is intended to discriminate patients who are really at risk of sudden death from patients for whom ICD implantation does not seem necessary. In addition, we designed an ad hoc classifier that capitalizes on prior knowledge on arrhythmogenesis. We conclude that improving prophylactic ICD-implantation candidate selection by automatic classification from Holter recording features may be possible. Nevertheless, that statement should be supported by the study of a more extensive and appropriate database.

Bakgrund: Tekniken utvecklas kontinuerligt och är idag ett vanligt inslag i sjuksköterskans dagliga omvårdnadsarbete. Patienter som vårdas av sjuksköterskan kommer också att komma i kontakt med tekniken och förståelse för patienters upplevelser är centralt för att sjuksköterskan ska kunna arbeta personcentrerat. Det är därmed väsentligt att belysa vad forskningen säger om hur patienter upplever att leva nära teknisk utrustning med anledning av att dessa patienter finns överallt i hälso- och sjukvården, och allmänsjuksköterskan kommer att komma i kontakt med dessa patienter.  Syfte: Syftet var att beskriva patienters upplevelser av att leva med en implanterbar kardiell defibrillator (ICD).  Metod: Litteraturöversikt med kvalitativ ansats baserad på 13 vetenskapliga artiklar från databaserna PubMed och Cinahl Complete. Artiklarna analyserades enligt Fribergs femstegsmodell för analys av kvalitativa studier.  Resultat: I litteraturöversiktens resultat presenterades tre teman och fem subteman. Patienter med ICD-behandling upplevde att kroppen med en ICD-dosa var förändrad. Relationen till livet förändrades och upplevelsen av chocken påverkade patienters mående. Patienter upplevde en brist på kunskap om hur ICD-behandlingen påverkade livet.  Slutsats: Patienter med ICD-behandling behövde anpassa sig till de förändringar och begränsningar som behandlingen medför. Hälso- och sjukvården behöver vara medvetna, ha förståelse och kunskap om förändringarna för att stödja och bevara hälsa och integritet, samt att begränsningar medför att relationen till samhället kan förändras. / Background: Technology is constantly developing and is now a common occurrencein the day-to-day work of a nurse. Patients who are in the care of anurse also come in contact with the technology, and being able tounderstand their experiences is key in allowing nurses to providepatient-centred care. It is therefore essential to highlight what researchsays about how patients experience living close to technical equipment,considering how these patients can be found everywhere in healthcare,and registered nurses will come in contact with these patients. Aim: The aim was to describe patients’ experiences living with an Implantable Cardioverter Defibrillator (ICD). Method: A literature review with a qualitative design based on 13 scientific articles from the databases PubMed and Cinahl Complete. The articles were analysed using Fribergs’ five step model for analysing qualitative studies. Results: In the literature review three themes and five subthemes were presented. Patient undergoing ICD-treatment experienced that their bodies felt different with the ICD-device. Their view of life changed as a result of the treatment and the shock of the defibrillation impacted their wellbeing. Patients experienced a lack of knowledge about how ICD-treatment affected their lives. Conclusion: Patients undergoing ICD-treatment needed to adapt to the changes and limitations that the treatment causes. The health care system needs to be aware of, have an understanding of and the knowledge of the changes in order to be able to support and maintain health and integrity. The limitations imposed a possible changing relationship with soceity.

Software testing, specifically in the medical device field, has become increasingly complex over the last decade. Technological enhancements to simulate clinical scenarios and advancements in communicating to medical devices have created the need for better testing strategies and methodologies. Typical medical device companies have depended on manual testing processes to fulfill Food and Drug Administration (FDA) submission requirements specifically Class III devices which are life supporting, life sustaining devices. At St. Jude Medical, software testing of Class III devices such as implantable cardioverter-defibrillators (ICDs), pacemakers, and pacing analyzers are given top priority to ensure the highest quality in each product. High emphasis is made on improving software testing for ease of use and for catching more software errors in each device. A significant stride in testing has automated the process and has provided software verification teams with the tools they need to successfully test and deliver high quality products. By creating software libraries which interact with communication to the other interfaces needed to test medical devices, test engineers can focus on fully testing device requirements and will not be concerned with how each test will interact with the device or any other testing tools. The main focus will be a specific St. Jude Medical device known as the Pacing System Analyzer (PSA). The PSA device will be used to demonstrate how verification engineers are able to benefit from software libraries and allow the testing process and test development to be fully automated. New technologies and standards will be created to simulate clinical scenarios and to communicate to new devices. The goal is to use software engineering principles to create standard test libraries which sustain these changes while still allowing testers to focus on finding issues for each device.

A estratificação de risco para morte súbita em pacientes com cardiomiopatia hipertrófica ainda é um desafio. Sua prevenção pelo cardiodesfibrilador automático é eficaz, porém, onerosa e não isenta de riscos. Pacientes com indicação de cardiodesfibrilador automático para prevenção primária, baseada em fatores de risco clínicos, apresentam baixa taxa de terapias apropriadas. Estudos que validem novos fatores de risco são necessários, visando identificar pacientes com maior probabilidade de morte súbita e, portanto, que se beneficiam do implante do dispositivo. Estudos que correlacionam a presença de realce tardio com arritmias ventriculares e morte súbita foram realizados, entretanto, sua aplicabilidade clinica ainda não é consenso. Objetivos: Avaliar, em portadores de cardiomiopatia hipertrófica, se a presença e a extensão de realce tardio, identificado pela tomografia computadorizada, correlaciona-se com a ocorrência de taquiarritmias ventriculares registradas no monitor de eventos do cardiodesfibrilador automático, durante um seguimento clínico ambulatorial. Métodos: Foram incluídos pacientes com cardiomiopatia hipertrófica dos ambulatórios de Eletrofisiologia e Miocardiopatias do Instituto Dante Pazzanese de Cardiologia. Os pacientes foram divididos em dois grupos: grupo I composto por aqueles que receberam terapia apropriada pelo cardiodesfibrilador automático ou tiveram apenas a documentação de taquicardia ventricular não sustentada pelo cardiodesfibrilador automático; grupo II, composto por pacientes sem documentação de arritmias ventriculares no monitor de eventos. As variáveis contínuas foram comparadas utilizando-se testes t de Student pareado ou Wilcoxon; para as categóricas o teste do x2. Para análise dos dados, utilizou-se o programa SPSS. Valores de p < 0,05 foram considerados estatisticamente significativos. Resultados: Sessenta e um pacientes (idade média 39±15 anos, 51% mulheres, com seguimento médio 5,13±3,0 anos) foram avaliados. Em 91,8%, a indicação do cardiodesfibrilador automático foi por prevenção primária. Durante o seguimento clínico, cinco pacientes (8,2%) apresentaram terapias apropriadas e 15 (24,6%) tiveram taquicardia ventricular não sustentada, mas sem terapia. A densidade de fibrose (incluindo massa de ventrículo esquerdo acometida e percentual de acometimento) não foi estatisticamente diferente entre os grupos I e II (4,3±4,8% vs 7,0±7,7% nos grupos I e II, respectivamente, p = 0,13). Entretanto, 85% dos pacientes com taquicardia ventricular apresentavam fibrose à tomografia computadorizada. Maiores densidades de fibrose se correlacionaram com idades mais jovens, com menores frações de ejeção e sexo masculino. Espessura septal >= 30mm se correlacionou à maior massa de fibrose. Houve correlação entre o surgimento de fibrilação atrial e maior porcentual de fibrose do ventrículo esquerdo. Dentre os fatores que se correlacionaram com maior densidade de fibrose, nenhum deles se correlacionou com eventos arrítmicos ventriculares. A associação dos fatores clínicos ou fatores clínicos isolados que motivaram a indicação do implante do cardiodesfibrilador automático não se correlacionou com eventos arrítmicos. Os pacientes do grupo I apresentaram maior diâmetro diastólico do ventrículo esquerdo e maior diâmetro do átrio esquerdo quando comparado com os pacientes do grupo II (47,7±4,7mm vs 43.1±5,4 mm, p = 0,002 e 47,8±8mm vs 41,5±7,1mm, p = 0,003, respectivamente). Conclusões: 1. A presença de fibrose detectada pela tomografia computadorizada apresenta razoável sensibilidade para identificação de pacientes com risco para taquicardia ventricular; 2. A densidade de fibrose foi similar nos pacientes dos grupos I e II; 3. Pacientes com fibrilação atrial apresentaram maior densidade de fibrose ventricular detectada pela tomografia computadorizada em comparação aos pacientes sem fibrilação atrial; 4. O diâmetro diastólico final de ventrículo esquerdo e o diâmetro atrial esquerdo associaram-se à maior risco de taquicardia ventricular; 5. Os fatores de risco convencionais, associados ou não à fibrose, não se correlacionaram com maior probabilidade de ocorrência de eventos arrítmicos ventriculares. / Risk stratification for sudden cardiac death in hypertrophic cardiomyopathy patients is still challenging. Primary prevention of sudden death with implantable cardioverter-defibrillator is an effective, however, costly and not risk-free method. Patients with implantable cardioverter-defibrillator indicated for primary prevention based on clinical risk factors display low rates of appropriate therapies. Studies evaluating new risk factors are needed seeking to identify who would be mostly at risk of sudden cardiac death, and therefore benefit from cardioverter-defibrillator. Studies have been conducted to establish a correlation between late enhancement and ventricular arrhythmias and sudden cardiac death; however, its clinical applicability is still controversial. Objective: To evaluate if the presence and extension of late enhancement, identified by computed tomography, correlates with the occurrence of ventricular arrhythmias in hypertrophic cardiomyopathy patients. Methods: Patients with hypertrophic cardiomyopathy followed in Electrophysiology and Cardiomyopathies divisions at Dante Pazzanese Institute of Cardiology were included in the study. Patients were divided into two groups: group I composed by those with appropriate therapies (shock or overdrive) or non-sustained ventricular tachycardia; and group II, composed by patients without documented ventricular arrhythmias. Continuous variables were compared using paired t-student test or Wilcoxon test. Categorical variables were analyzed using chi-square test. For data analysis, the SPSS program was used. P values < 0.05 were considered statistically significant. Results: Sixty one patients (mean age 39 ± 15 years, 51% female, average follow up 5.13 ± 3 years) were evaluated. In 91.8%, cardioveter-defibrillator was indicated by primary prevention. During the follow up, five patients (8.2%) had appropriate therapies and 15 (24.6%) presented non-sustained ventricular tachycardia without therapies. Fibrosis density, (including left ventricular mass compromise and percentage) was not statistically different between the groups (4.3±4.8% for group I vs. 7.0±7.7% for group II, p =0.13). However, 85% of patients with ventricular tachycardia had fibrosis on cardiac computed tomography. Larger fibrosis density correlated with younger age, reduced ejection fraction and male gender. Septum >30 mm correlated with fibrosis mass. There was a correlation between atrial fibrillation and higher left ventricular fibrosis percentage. Among the factors that correlated with higher fibrosis density, none of them had correlation with ventricular arrhythmic events. The combination of clinical factors that motivated the implantation of cardioverter-defibrillator did not correlate with arrhythmic events. Patients at group I had larger left ventricular diastolic diameter (47.7±4.7 vs. 43.1±5.4mm, respectively, p= 0.002) and left atrium diameter (47.8±8.2 vs. 41.5±7.1 mm, respectively, p=0.003). Conclusions: 1. The presence of fibrosis detected by cardiac tomography had reasonable sensitivity to identify patients at risk of ventricular tachycardia; 2. Fibrosis density was similar between groups I and II; 3. Patients with atrial fibrillation had more fibrosis density detected by cardiac tomography compared to patients without atrial fibrillation; 4. Left ventricular end diastolic diameter and left atrial diameter correlated with increased risk of ventricular tachycardia; 5. Classical risk factors, associated or not with fibrosis, did not correlate with increased probability of ventricular arrhythmic events.

Dispositional optimism, as a stable outcome expectancy, has been shown to predict health outcomes in several contexts. Research has demonstrated that health-impaired subjects with optimistic outlooks fared better than those with a pessimistic outlook. Choice of coping strategies has been theorized as the mediating factor through which optimism operates. However, the construct of dispositional optimism has been challenged as a polar opposite of neuroticism, thus contending that optimism is not an independent notion. The present study was designed to evaluate further the theoretical underpinnings of dispositional optimism theory. Subjects were selected from a population of cardiac patients who received an automatic implantable cardioverter defibrillator (AICD). This device, designed to save the patient from sudden cardiac death, dispenses an electric shock to the heart should it exhibit sustained ventricular tachycardia or fibrillation. This research project examined the relationship of dispositional optimism, coping, and neuroticism to psychological distress, life satisfaction, health perception, and frequency of prior AICD discharges. Intact data from 50 of the 60 participants were examined in multiple regression analyses. The results of the analyses were diverse. Principal findings were (a) general psychological distress was predicted solely by neuroticism but optimism predicted the majority of unique variance in the "style" with which subjects approach the assessment of distress; (b) optimism was subsumed under neuroticism in predicting health perception; (c) avoidance coping interacted with optimism in predicting a significant amount of unique variance over and above neuroticism in the number of AICD discharges experienced by the patients. In this latter finding, pessimistic patients who did not use avoidance coping received a greater number of discharges. Thus, optimism and neuroticism were not parallel constructs in all dependent variables. Also, the optimism/avoidance coping interaction in predicting an actual medical outcome was unprecedented. Limitations and directions for future research were discussed.