Márcio Augusto Silva

Type I atrial flutter radiofrequency ablation. Importance of bidirectional line of block in the inferior vena cava tricuspide annulus isthmus

PURPOSE: To determine the clinical importance of a bi-directional line of block demonstration in the inferior vena cava-tricuspid annulus isthmus as an end-point for radiofrequency (RF) atrial flutter (FL) ablation. METHODS: Forty consecutive patients (51±11 years) with type I FL were divided in 2 groups: GI (30 patients) anatomic, non-electrophysiologic isthmus ablation technique (interruption and non-induction FL criteria); and GII (10 patients) anatomic with electrophysiologic evaluation of bi-directional isthmus conduction. The isthmus activation was analyzed before and after anatomic RF ablation with a cateter exploring each side of the line of block, depending on the conduction evaluation (anterograde or retrograde). RESULTS: FL was interrupted and not reinduced in 26/30 (86.6%) GI patients and in 10 (100%) GII patients (p= 0.5558). During follow-up FL recurred in 30% of the patients in both groups. In GII, 6 patients with bi-directional block remained assymptomatic, whereas 3 patients with unidirectional block presented recurrence (p= 0.012). CONCLUSION: Electrophysiologic demonstration of bi-directional line of block in the isthmus is related to long-term success and should be the criterion for interruption of type I atrial FL RF ablation.PURPOSE To determine the clinical importance of a bi-directional line of block demonstration in the inferior vena cava-tricuspid annulus isthmus as an end-point for radiofrequency (RF) atrial flutter (FL) ablation. METHODS Forty consecutive patients (51 +/- 11 years) with type I FL were divided in 2 groups: GI (30 patients) anatomic, non-electrophysiologic isthmus ablation technique (interruption and non-induction FL criteria); and GII (10 patients) anatomic with electrophysiologic evaluation of bi-directional isthmus conduction. The isthmus activation was analyzed before and after anatomic RF ablation with a cateter exploring each side of the line of block, depending on the conduction evaluation (anterograde or retrograde). RESULTS FL was interrupted and not reinduced in 26/ 30 (86.6%) GI patients and in 10 (100%) GII patients (p = 0.5558). During follow-up FL recurred in 30% of the patients in both groups. In GII, 6 patients with bi-directional block remained assymptomatic, whereas 3 patients with unidirectional block presented recurrence (p = 0.012). CONCLUSION Electrophysiologic demonstration of bidirectional line of block in the isthmus is related to long-term success and should be the criterion for interruption of type I atrial FL RF ablation.

Relação entre a persistência da condução pela via lenta nodal após ablação de taquicardia por reentrada nodal e a recorrência clínica

PURPOSE: The aim of this study is to verify whether the persistence of conduction over the slow pathway is related to an increased trend for recurrence. METHODS: Recurrence rate was retrospectively analyzed in 126 patients who underwent slow pathway radiofrequency (RF) catheter ablation during a follow-up of 20±12 months. The ablative procedure was interrupted when AVNRT was no longer induced by atrial stimulation after intravenous infusion of isoproterenol. Ninety-eight patients had no evidence of slow pathway whereas 28 patients persisted with AV node jump and atrial echo beat. RESULTS: There were 15 recurrences: 9% of those who had no evidence of slow pathway (9 of 98 patients) and 21% of those with AV node jump and/or atrial echo beat but this difference was not statistically significant. CONCLUSION: As long as AVNRT cannot be induced by atrial pacing and isoproterenol infusion after slow pathway RF catheter ablation, the presence of AV node jump and/or atrial echo beat does not increase the risk of recurrence of AVNRT.PURPOSE The aim of this study is to verify whether the persistence of conduction over the slow pathway is related to an increased trend for recurrence. METHODS Recurrence rate was retrospectively analyzed in 126 patients who underwent slow pathway radiofrequency (RF) catheter ablation during a follow-up of 20 +/- 12 months. The ablative procedure was interrupted when AVNRT was no longer induced by atrial stimulation after intravenous infusion of isoproterenol. Ninety-eight patients had no evidence of slow pathway whereas 28 patients persisted with AV node jump and atrial echo beat. RESULTS There were 15 recurrences: 9% of those who had no evidence of slow pathway (9 of 98 patients) and 21% of those with AV node jump and/or atrial echo beat but this difference was not statistically significant. CONCLUSION As long as AVNRT cannot be induced by atrial pacing and isoproterenol infusion after slow pathway RF catheter ablation, the presence of AV node jump and/or atrial echo beat does not increase the risk of recurrence of AVNRT.OBJETIVO: Verificar se a persistencia de salto nodal relaciona-se a taxa de recorrencia de taquicardia por reentrada nodal (TRN) apos ablacao com radiofrequencia (RF) da via lenta do no atrioventricular. METODOS: Num seguimento de 20±12 meses, foi analisada a recorrencia de TRN em 126 pacientes consecutivos submetidos a ablacao com RF da via lenta nodal. O criterio de interrupcao do procedimento foi a nao reinducao da TRN, apos estimulacao atrial programada, com e sem isoproterenol intravenoso. Ao final do procedimento, 98 pacientes nao apresentavam salto nodal, e em 28 persistia o salto nodal e/ou o eco atrial. RESULTADOS: Houve recorrencia clinica de TRN em 15 (11%) pacientes: 9 no grupo sem salto nodal e/ou eco atrial e em 6 do grupo que persistiu com salto e/ou eco atrial. A recorrencia tendeu a ser maior no 2o grupo (9% vs 21%), mas nao houve significância estatistica entre os resultados (p=0,09). CONCLUSAO: Desde que a TRN nao possa ser induzida apos a infusao de isoproterenol, a recorrencia espontânea da arritmia apos a ablacao por RF da via lenta nodal nao e diferente entre pacientes que persistem ou nao com salto nodal e/ou eco atrial.

Scalable data center provisioning and control

The problem of provisioning servers in a data center environment includes coordinating access to and sharing of physical resources, loading servers with the appropriate software images, supporting storage access to users and applications, and providing basic monitoring and control services for those servers. We have developed and adapted systems--Hop-scotch, Sysman, and the InfiniBande-attached IBM Storage Area Network (SAN) Volume Controller (SVC)--that automate the provisioning and monitoring processes for large collections of servers. Our solution relies on directory services to implement access control. It uses network boot disks and managed root disks to control the image of each server. We leverage the IBM Global Storage Architecture and SVC to provide storage to users and applications. Finally, interfaces are provided to access the services both programmatically and interactively.

Fiber-based testbed architecture enabling advanced experimental research

In 2005, the creation of the network for the Kyatera project began, with the declared goal of designing the most advanced and innovative research and experimental network of Latin America. This paper describes the groundwork for the development of such network in terms of its requirements, functionalities, provided services, enabled researches and design concepts. Structurally, the Kyatera network is composed of three sub-networks that will enable parallel experiments and research to be carried out in optical, networking and applications domains. Given the services and the technologies deployed, it will promote the development of joint experiments with peer advanced research centers both national and international

Taquicardia ventricular polimórfica durante teste de inclinação na doença de Chagas

1. Especialista em marcapasso, eletrofisiologista da Clínica do Ritmo, Vitória, ES, Brasil. 2. Doutor em Cardiologia, eletrofisiologista da Clínica do Ritmo, Vitória, ES, Brasil. 3. Especialista em Eletrofisiologia, eletrofisiologista da Clínica do Ritmo, Vitória, ES, Brasil. 4. Habilitado em Estimulação Cardíaca Artificial, eletrofisiologista da Clínica do Ritmo, Vitória, ES, Brasil. Correspondência: Jorge Elias Neto Av. Nossa Sra. dos Navegantes, 451/814 – Enseada do Suá Vitória, ES, Brasil – CEP 29050-335 E-mail: jeliasneto@gmail.com Artigo submetido em 8/2016. Artigo publicado em 6/2017. RESUMO Paciente do sexo masculino, de 62 anos de idade, com megacólon chagásico sem manifestações cardíacas, apresentou evento sincopal sem pródromos, sendo submetido a Holter de 24 horas, ecocardiografia, teste ergométrico e cineangiocoronariografia, que se mostraram normais. O estudo eletrofisiológico mostrou ausência de distúrbios de condução e de indução de taquiarritmias. Durante a fase basal do teste de inclinação, o paciente apresentou taquicardia ventricular polimórfica. Foi realizado implante de cardioversor-desfibrilador implantável. Na evolução, apresentou deterioração da função ventricular com início de terapêutica específica. Após sete anos de acompanhamento, observaram-se três episódios de taquicardia ventricular polimórfica adequadamente revertidos pelo cardioversor-desfibrilador implantável. DESCRITORES: Taquicardia Ventricular; Teste da Mesa Inclinada; Doen ça de Chagas; Síncope. ABSTRACT A 62 year-old man with Chagasic megacolon without cardiac manifestations developed a syncope without prodrome and was submitted to 24-hour Holter monitoring, echocardiogram, exercise test and coronary angiography. Electrophysiology tests showed there was no conduction and tachyarrhythmia induction disorders. During the baseline phase of the tilt test, the patient presented a polymorphic ventricular tachycardia. An implantable cardioverter defibrillator was implanted. At the follow-up, the patient presented left ventricular deterioration and specific therapy was started. After seven years of follow-up, three episodes of polymorphic ventricular tachycardia were observed and were successfully converted.

Evaluating Overlays for Gigabit Channels Data Communication

The widespread use of the Internet and the rise of new technologies pose a set of challenges to its current architecture and shows shortcomings in routing, naming, addressing and security. To overcome these shortcomings structural changes to current Internet architecture might be needed, a difficult task in face of the constitutive force that comes from the huge installed base of the current Internet. In order to address this situation, several forms of incremental introduction in the form of new technologies, protocols and applications present itself as more viable alternatives, overlay networks being one of the most prominent ones. This work intends to investigate performance issues that can impact the viability of adopting overlays as data transport over high-speed Gigabit networks, focusing on three different overlay proposals: HIP (host identification protocol), i3 (Internet indirection infrastructure), and H13 (host identity indirection infrastructure).