Abstract Introduction: It is challenging to diagnose syncope in patients with pacemakers. Because these patients have increased morbidity and mortality risks, they require immediate attention to determine the causes in order to provide appropriate treatment. This study aimed to investigate the causes and predictive factors of syncope as well as the methods used to diagnose syncope in cardiac pacemaker patients. Methods: Patients with pacemakers implanted owing to sinus node disease or atrioventricular block were evaluated with standardized questionnaires, endocavitary electrograms, and other tests based on the suspected causes of syncope. Mann-Whitney U tests were used to analyze continuous variables and Chi-squared or Fisher’s exact tests were used for categorical variables. Logistic regression was used for multivariate analyses. Statistical significance was P<0.05. Results: The study included 95 patients with pacemakers: 47 experienced syncope in the last 12 months and 48 did not. Of the 100 documented episodes of syncope, 48.9% were vasovagal syncopes, 17% had cardiac-related causes, 10.6% had unknown causes, and 8.5% had pacemaker failure. The multivariate analysis showed that a New York Heart Association (NYHA) Functional Class II was a significant factor for developing syncope (P<0.01). Conclusion: While the most common type of syncope in pacemaker patients was neurally mediated, it is important to perform detailed evaluations in this population as the causes of syncope can be life-threatening. The best diagnostic methods were stored electrogram analysis and the tilt table test. NYHA Functional Class II patients were found to have a higher risk for syncope.

Resumo Fundamento: A evolução do paciente chagásico após implante de cardiodesfibrilador implantável (CDI) é tema ainda controverso. Objetivo: Comparar a evolução clínica pós-implante do CDI em pacientes com cardiopatia chagásica crônica (CCC) e cardiopatia isquêmica (CI). Métodos: Trata-se de um estudo prospectivo histórico de uma população de 153 pacientes portadores de CDI, sendo 65 com CCC e 88 com CI. Os dispositivos foram implantados entre janeiro de 2003 e novembro de 2011, tendo-se comparado a taxa de sobrevida e a sobrevida livre de eventos entre essas populações. Resultados: Os grupos foram similares na predominância do sexo masculino, classe funcional e fração de ejeção. Os pacientes isquêmicos são em média 10 anos mais velhos que os chagásicos (p < 0,05). Os pacientes chagásicos apresentavam escolaridade e renda mensal mais baixa do que os isquêmicos (p < 0,05). Foi demonstrado que o número de terapias apropriadas nos pacientes com CCC é 2,07 vezes maior do que naqueles com CI. A incidência de choque apropriado é maior na CCC (p < 0,05). As taxas de mortalidade anual nos dois grupos foram similares, assim como a incidência de tempestade elétrica. Não houve nenhuma morte súbita nos pacientes com CCC e apenas uma nos pacientes com CI. Não houve diferença estatisticamente significativa no tempo de sobrevida entre os dois grupos (p = 0,720) nem na sobrevida livre de eventos (p = 0,143). Conclusão: A CCC duplica o risco de receber terapias apropriadas em relação à CI, mostrando assim maior complexidade das arritmias nos pacientes chagásicos.

Abstract Background: The outcome of Chagas disease patients after receiving implantable cardioverter defibrillator (ICD) is still controversial. Objective: To compare clinical outcomes after ICD implantation in patients with chronic Chagas cardiomyopathy (CCC) and ischemic heart disease (IHD). Methods: Prospective study of a population of 153 patients receiving ICD (65 with CCC and 88 with IHD). The devices were implanted between 2003 and 2011. Survival rates and event-free survival were compared. Results: The groups were similar regarding sex, functional class and ejection fraction. Ischemic patients were, on average, 10 years older than CCC patients (p < 0.05). Patients with CCC had lower schooling and monthly income than IHD patients (p < 0.05). The number of appropriate therapies was 2.07 higher in CCC patients, who had a greater incidence of appropriate shock (p < 0.05). Annual mortality rate and electrical storm incidence were similar in both groups. There was no sudden death in CCC patients, and only one in IHD patients. Neither survival time (p = 0.720) nor event-free survival (p = 0.143) significantly differed between the groups. Conclusion: CCC doubles the risk of receiving appropriate therapies as compared to IHD, showing the greater complexity of arrhythmias in Chagas patients.

ResumoFundamento:A terapia de ressincronização cardíaca pode demonstrar resultados desfavoráveis em 30-40% dos casos.Objetivo:Este estudo teve por objetivo desenvolver modelos preditores para o desfecho combinado de morte cardíaca ou transplante (Tx) em diferentes estágios da terapia de ressincronização cardíaca (TRC).Métodos:Estudo prospectivo observacional de 116 pacientes com idade média de 64,8 ± 11,1 anos, dos quais 68,1% estavam em classe funcional (CF) III e 31,9% em classe IV ambulatorial. Variáveis clínicas, eletrocardiográficas e ecocardiográficas foram avaliadas com regressão de Cox e curvas de Kaplan-Meier.Resultados:O desfecho mortalidade/Tx cardíacos foi de 16,3% durante seguimento de 34,0 ± 17,9 meses. No período pré-implante, disfunção ventricular direita (DVD), fração de ejeção < 25% e uso de altas doses de diuréticos (ADD) aumentaram o risco de morte e Tx cardíacos em 3,9, 4,8 e 5,9 vezes, respectivamente. No primeiro ano após TRC, DVD, AHDD e hospitalização por insuficiência cardíaca congestiva elevaram o risco de morte (razões de risco de 3,5, 5,3 e 12,5, respectivamente). No segundo ano após TRC, DVD e CF III/IV foram fatores de risco significativos de mortalidade no modelo multivariado de Cox. As acurácias dos modelos foram 84,6% na pré-implante, 93% no primeiro ano após TRC e 90,5% no segundo ano após TRC. Os modelos foram validados por bootstrapping.Conclusão:Desenvolvemos modelos preditores de morte e Tx cardíacos em diferentes estágios de TRC com base na análise de variáveis clínicas e ecocardiográficas simples e de fácil obtenção. Os modelos mostraram boa acurácia e ajuste, foram validados internamente e são úteis para a seleção, o monitoramento e a orientação de pacientes indicados para TRC.

AbstractBackground:30-40% of cardiac resynchronization therapy cases do not achieve favorable outcomes.Objective:This study aimed to develop predictive models for the combined endpoint of cardiac death and transplantation (Tx) at different stages of cardiac resynchronization therapy (CRT).Methods:Prospective observational study of 116 patients aged 64.8 ± 11.1 years, 68.1% of whom had functional class (FC) III and 31.9% had ambulatory class IV. Clinical, electrocardiographic and echocardiographic variables were assessed by using Cox regression and Kaplan-Meier curves.Results:The cardiac mortality/Tx rate was 16.3% during the follow-up period of 34.0 ± 17.9 months. Prior to implantation, right ventricular dysfunction (RVD), ejection fraction < 25% and use of high doses of diuretics (HDD) increased the risk of cardiac death and Tx by 3.9-, 4.8-, and 5.9-fold, respectively. In the first year after CRT, RVD, HDD and hospitalization due to congestive heart failure increased the risk of death at hazard ratios of 3.5, 5.3, and 12.5, respectively. In the second year after CRT, RVD and FC III/IV were significant risk factors of mortality in the multivariate Cox model. The accuracy rates of the models were 84.6% at preimplantation, 93% in the first year after CRT, and 90.5% in the second year after CRT. The models were validated by bootstrapping.Conclusion:We developed predictive models of cardiac death and Tx at different stages of CRT based on the analysis of simple and easily obtainable clinical and echocardiographic variables. The models showed good accuracy and adjustment, were validated internally, and are useful in the selection, monitoring and counseling of patients indicated for CRT.