This is an electrocardiological study, based on electrocardiographic analysis of new cases as well as on a review of some features, hitherto unrecognized or not stressed, in subjects with these disorders, that may help throw more light on them. In six cases studied personally using intracardiac electrography - the technique of His bundle electrography - the contribution and relevance of this method will be analysed, and the results compared with the conclusions drawn from other contemporary work in this field. Thus, the clinical presentation of the cases, and of these syndromes, receives secondary attention, and more detailed analysis only when appropriate to substantiate the main burdens of the thesis. These case reports appear separately in Section c. The mechanism of production of arrhythmias is becoming much better understood, and some of the diagnostic measures that are discussed in this work provide a clearer picture of their genesis. It is not proposed to embark upon a detailed consideration of anti-arrhythmic therapy in these syndromes, but the general principles will be discussed, and special reference will also be made to some new developments in this field.

Propranolol, a first-generation nonselective β-adrenoceptor blocking agent, is commonly used to treat pediatric arrhythmias. Atenolol, relatively long-acting, cardioselective β-adrenoceptor blocking agent, has been successfully used in adults with supraventricular tachycardia (SVT). There is only one report on the use of atenolol in children with SVT, and our report is on the first long-term prospective study to evaluate the use of atenolol in children. A group of 22 children <18 years of age with clinical SVT were enrolled in the study. The tachycardia was documented on electrocardiograms in each case and was confirmed by electrophysiologic studies in some. Once- a-day oral atenolol was started as a monotherapy. Of the 22 children with various types of SVT, 13 (59%) were well controlled on long-term oral atenolol therapy. The effective dose of atenolol ranged between 0.3 and 1.3 mg/kg/day (median effective dose 0.7 mg/kg/day). Five children had some adverse effects. However, none in the successful group of 13 patients required drug discontinuation because of such effects. Once-a-day oral atenolol as a monotherapy is effective and relatively safe for long-term management of SVT during childhood. It is an attractive alternative β- adrenoceptor blocking agent for the management of pediatric arrhythmias.

The location of accessory pathways in Wolff-Parkinson-White syndrome patients is performed manually during open heart surgery at Groote Schuur Hospital, using a hand-held roving electrode. This manual procedure is slow and tedious, prolonging the operation and the time for which the patient remains on cardiac bypass. A multichannel electrogram acquisition and display system with a storage facility would significantly reduce the time taken and improve the reliability of locating the accessory pathways. Having considered a number of currently available cardiac mapping systems it was decided that a new system be developed for specific application within Groote Schuur Hospital. The main design goals of this system are to improve accuracy, increase reliability and enhance the speed of the entire mapping procedure with direct benefit to staff and patients. The system is based on an IBM compatible computer and allows for the acquisition of a maximum of thirty-two electrogram inputs. A typical configuration would acquire twenty epicardial, two references (one each from atrium and ventricle), one roving electrode and two surface lead signals. The epicardial signals are obtained from a custom-built electrode belt which is placed around the heart over the atrioventricular groove. The project includes the development of front-end hardware and software for processing, display and storage of electrogram signals. The relative activation times of the signals are displayed under software control in order to facilitate the location of any accessory pathway(s).

Coral disease represents one of the many challenges facing coral reefs, and is a contributing factor to the overall decline in coral reef health worldwide. An increase in disease frequency, outbreaks and the emergence of new diseases has fuelled much concern over the impact of coral diseases and subsequently prompted research into their possible causes. Our understanding of putative coral pathogens has lagged behind the emergence of coral disease as a major threat to the health of coral reefs. The Great Barrier Reef (GBR) is the largest contiguous reef in the world, and is still regarded as one the healthiest and best managed coral reef ecosystems in existence today. Despite this, the frequency of coral disease has begun to increase sharply over the past decade, prompting researchers to focus on the aetiology, causal factors and ecological impact of coral disease within the Great Barrier Reef Marine Park (GBRMP). This PhD thesis focused on two distinct disease elements: brown band (BrB) and white syndrome (WS). These two diseases affect corals within the GBRMP, yet their microbiology and ecology is largely unknown. The research project investigated the microbiology and ecology of WS and BrB affecting acroporids, using culture-dependent and independent methods to characterise the microbial community associated with healthy and diseased corals and identify putative coral pathogens. The lifecycle and diurnal cycles of BrB ciliates were also explored to gain a greater understanding of the effect of these ciliates on coral health. Ecological surveys were carried out at Heron Island sites commonly used for the collection of corals to ascertain the prevalence and significance of these diseases in the context of laboratory results. Surveys at five sites revealed a mean prevalence of 8.11% of tabular acroporids affected by WS, which is consistent with previous studies. BrB revealed a much lower prevalence of less than 0.04%. Bacterial 16S rRNA gene clone libraries were constructed from Acropora hyacinthus samples derived from a healthy control colony, and a healthy section and lesion border of a WS affected colony. Distinct shifts in the microbial community and partitioning between the lesion border and healthy section of the diseased colony were observed. In addition, the healthy section of the diseased colony displayed a different microbial community to the control colony, supporting previous data that a microbial shift occurs preceding visible signs of infection. A number of bacteria from the healthy section of diseased coral shared close sequence affiliations to a number of Vibrio spp., including potentially pathogenic Vibrio species. Sequences retrieved from the lesion border of WS affected Acropora hyacinthus were dominated by Pseudoalteromonas spp., although these species have not been previously implicated in coral disease. The coral disease BrB is characterised by the presence of a brown ciliate band and these ciliates have been identified as a new species belonging to the class Oligohymenophorea, subclass Scuticociliatia. Within BrB-affected Acropora muricata, numerous filamentous, coccoid and rod bacteria were observed to be closely associated with the ciliate band, but absent in coral tissue adjacent to the typical brown band. It is unknown whether the bacteria associated with the mass of ciliates are the primary pathogens, a food source for the ciliates or simply opportunistic pathogens. Several isolates retrieved from BrB corals were tested for their pathogenicity in controlled infection trials using Acropora muricata. The preliminary results identified at least two isolates of interest (CC1 and HB-8). However, the results of a replicated infection trial failed to conclusively identify the bacteria as the causative agents of this disease. The findings from the cross-infection trials and ecological surveys suggest that BrB is an infectious but not highly contagious coral disease. This study revealed important aspects of both WS and BrB that were previously unknown. The research carried out has built a greater understanding, and a platform for future research directed at understanding key processes involved in these coral diseases. This research has highlighted the need for ongoing infection trials in diseases, even when a pathogen has been identified. The discovery of possible key bacterial species involved in WS and BrB warrants further research aimed at understanding the mechanisms in which bacteria may affect the coral holobiont. In conclusion, this research has further supported the notion that corals are a complex community with bacterial, animal and protistan partners, which when disturbed may see one or several of the previous benign partners becoming pathogenic. In a rapidly changing climate, this conclusion is consistent with the idea that coral diseases are on the rise due to changing environmental circumstances disturbing the balance between these interdependent partners.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.

Made available in DSpace on 2014-06-11T19:24:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-31Bitstream added on 2014-06-13T20:31:48Z : No. of bitstreams: 1 garbelinijunior_b_me_botfm.pdf: 899004 bytes, checksum: 3e76b67a9e7829e0f9fe15812c489d4f (MD5) / Universidade Estadual Paulista (UNESP) / As arritmias cardíacas são uma importante causa de morte relacionada ao sistema cardiovascular. Entre os vários tipos de arritmias, a Síndrome de Wolff-Parkinson-White se destaca por crises recorrentes de taquicardia, que acontecem com mais frequência no primeiro ano de vida, na adolescência e nas pessoas acima dos 60 anos. Eventualmente, a morte súbita pode ser uma manifestação dessa síndrome, o que acontece mais frequentemente em adultos jovens. A ablação por cateter com radiofrequência tem sido amplamente utilizada nos pacientes com recorrência das taquicardias, pacientes reanimados de morte súbita, pacientes pouco sintomáticos e nos assintomáticos. Avaliar a efetividade e a segurança da ablação por cateter com radiofrequência comparada ao tratamento com antiarrítmicos para pacientes com Síndrome de Wolff-Parkinson-White. Revisão sistemática de estudos clínicos aleatorizados, seguindo a metodologia da Colaboração Cochrane. Realizamos, nas principais bases de dados, uma estratégia de busca para a identificação de estudos clínicos prospectivos, aleatorizados que compararam ablação por cateter versus tratamento com antiarrítmico. Os artigos foram recuperados eletronicamente e manualmente por meio de referências. Dois revisores, independentemente, avaliaram os artigos, excluindo os que não tinham o escopo dessa revisão. 222 artigos foram identificados pela estratégia de busca. Todos os artigos foram excluídos. Não encontramos evidências na literatura que comprovem que a ablação por cateter é mais efetiva e segura que o tratamento antiarrítmico para todos os portadores de Síndrome de Wolff-Parkinson-White / Cardiac arrhythmias are an important cause of death related to cardiovascular system. Among the various types of arrhythmias, Wolff-Parkinson-White syndrome is distinguished by recurrent episodes of tachycardia that occur more frequently in the first year of life, in adolescence and in people over 60 years old. Eventually, sudden death can be a manifestation of this syndrome, which happens more often in young adults. The radiofrequency catheter ablation has been widely used in patients with recurrence of tachycardia, patients resuscitated from sudden death, mildly symptomatic and asymptomatic patients. To evaluate the effectiveness and safety of radiofrequency catheter ablation compared with antiarrhythmic treatment for Wolff-Parkinson-White syndrome patients. A systematic review of randomized clinical trials, following the methodology of the Cochrane Collaboration. We carried out a search strategy in the main databases to identify randomized prospective clinical trials comparing catheter ablation versus antiarrhythmic therapy. The articles were retrieved electronically and manually by reference. In an independent manner, two reviewers evaluated the articles, excluding those that did not have the scope of this review. 222 articles were identified by search strategy. All articles were excluded. In the literature, it was found no evidence that catheter ablation is more effective and safer than antiarrhythmic treatment for all patients with Wolff-Parkinson-White syndrome

Orientador: Antônio José Maria Cataneo / Coorientador: Paulo Eduardo de Oliveira Carvalho / Banca: Olavo Ribeiro Rodrigues / Banca: Márcio Nobrega / Resumo: As arritmias cardíacas são uma importante causa de morte relacionada ao sistema cardiovascular. Entre os vários tipos de arritmias, a Síndrome de Wolff-Parkinson-White se destaca por crises recorrentes de taquicardia, que acontecem com mais frequência no primeiro ano de vida, na adolescência e nas pessoas acima dos 60 anos. Eventualmente, a morte súbita pode ser uma manifestação dessa síndrome, o que acontece mais frequentemente em adultos jovens. A ablação por cateter com radiofrequência tem sido amplamente utilizada nos pacientes com recorrência das taquicardias, pacientes reanimados de morte súbita, pacientes pouco sintomáticos e nos assintomáticos. Avaliar a efetividade e a segurança da ablação por cateter com radiofrequência comparada ao tratamento com antiarrítmicos para pacientes com Síndrome de Wolff-Parkinson-White. Revisão sistemática de estudos clínicos aleatorizados, seguindo a metodologia da Colaboração Cochrane. Realizamos, nas principais bases de dados, uma estratégia de busca para a identificação de estudos clínicos prospectivos, aleatorizados que compararam ablação por cateter versus tratamento com antiarrítmico. Os artigos foram recuperados eletronicamente e manualmente por meio de referências. Dois revisores, independentemente, avaliaram os artigos, excluindo os que não tinham o escopo dessa revisão. 222 artigos foram identificados pela estratégia de busca. Todos os artigos foram excluídos. Não encontramos evidências na literatura que comprovem que a ablação por cateter é mais efetiva e segura que o tratamento antiarrítmico para todos os portadores de Síndrome de Wolff-Parkinson-White / Abstract: Cardiac arrhythmias are an important cause of death related to cardiovascular system. Among the various types of arrhythmias, Wolff-Parkinson-White syndrome is distinguished by recurrent episodes of tachycardia that occur more frequently in the first year of life, in adolescence and in people over 60 years old. Eventually, sudden death can be a manifestation of this syndrome, which happens more often in young adults. The radiofrequency catheter ablation has been widely used in patients with recurrence of tachycardia, patients resuscitated from sudden death, mildly symptomatic and asymptomatic patients. To evaluate the effectiveness and safety of radiofrequency catheter ablation compared with antiarrhythmic treatment for Wolff-Parkinson-White syndrome patients. A systematic review of randomized clinical trials, following the methodology of the Cochrane Collaboration. We carried out a search strategy in the main databases to identify randomized prospective clinical trials comparing catheter ablation versus antiarrhythmic therapy. The articles were retrieved electronically and manually by reference. In an independent manner, two reviewers evaluated the articles, excluding those that did not have the scope of this review. 222 articles were identified by search strategy. All articles were excluded. In the literature, it was found no evidence that catheter ablation is more effective and safer than antiarrhythmic treatment for all patients with Wolff-Parkinson-White syndrome / Mestre

Coral diseases were first noted in the 1960s and 1970s and have had major impacts globally on coral reef community structures. In the Caribbean, a major outbreak of white band disease has been considered responsible for the drastic decline of Caribbean Acroporids since the 1970s. In addition to white band disease, another more recently described condition known as rapid tissue loss (RTL) has had major impacts on Acropora cervicornis populations, specifically offshore Broward County Southeast Florida. While these diseases have contributed to the population decline, determining their etiologies has been elusive. Coral diseases have been characterized by shifts in their microbial counterparts within many levels of the coral host. While some coral diseases have had specific pathogens identified, research has not been able to determine pathogens for most. Evidence points toward bacterial causes for many diseases, but due to the complexity of the coral holobiont and the interaction with the environment, elucidating the causes has proven difficult. Many studies have examined the microbiomes of specific diseases and determined some potential pathogens or at least taxa playing important roles in the disease, although none have looked at RTL. Recognizing the local affect of RTL on A. cervicornis, this study set out to gain a baseline understanding of the healthy and RTL affected microbiome of A. cervicornis. 16S rRNA gene sequencing was used to examine the microbiome of completely healthy colonies, healthy regions of diseased colonies, and the disease margin of diseased colonies. Analysis of four microbial diversity metrics revealed marked increases in diversity with respect to declining health states. Additionally, community dissimilarity analysis and analysis of differentially abundant taxa exhibited distinct microbial community structures due to coral health. Several highly abundant (Rickettsiales, Rhodobacteraceae) and a few low abundance (Bdellovibrionales) taxa were identified as primary drivers of the differences. Additionally, Piscirickettsiaceae, a known fish pathogen, was consistently associated with RTL and warrants further investigation. All of the taxa identified with in RTL have been associated with other Acroporid and non-Acroporid diseases throughout the Caribbean and the rest of the world. The consistent IV association of similar taxa for coral diseases around the world, including those found in this study, supports the recent ideas of non-specific primary pathogens. While most disease studies, coral and otherwise, aim to determine a single pathogen for a single disease, this study and others suggest there could be a multitude of organisms responsible for the disease. Therefore understanding the interactions of the coral holobiont and the environment is important to understanding coral disease. While this study reveals significant changes in the bacterial community associated with RTL as well as some potential pathogens, the relationships appear complex and perhaps at a functional level rather than merely taxonomic. Furthermore, this study did not examine viruses, fungi, or protists, which could be possible pathogens. Therefore, to further develop an understanding of RTL and many other coral diseases it will be necessary to consider additional none-bacterial members of the holobiont as well as the bacterial functions and taxa coupled with the roles of environmental factors.