ResumoFundamento:A documentação de eventos arrítmicos (EA) em candidatos a transplante renal (CTR) submetidos à diálise é limitada pelo registro de eletrocardiograma convencional. Um monitoramento contínuo do ritmo cardíaco parece ser o procedimento mais adequado para a detecção automática de arritmia, contudo esse método não foi explorado anteriormente.Objetivo:O objetivo deste estudo foi investigar a incidência e os preditores de EA em CTR usando um gravador de eventos implantável, do inglês, “loop recorder implantável” (ILR).Métodos:Um estudo prospectivo observacional foi conduzido entre Junho/2009 a Janeiro/2011. Cem CTR ambulatoriais consecutivos foram submetidos ao ILR e acompanhados pelo menos por um ano. Uma regressão logística multivariada foi aplicada para definir os preditores de EA.Resultados:Durante o tempo médio de acompanhamento de 424 ± 127 dias, EA foram detectados em 98% dos pacientes, sendo que 92% deles tinham mais de um tipo de arritmia, a maioria não considerada potencialmente séria. Taquicardia atrial sustentada e fibrilação atrial ocorreram respectivamente em 7% e 13% dos pacientes; bradiarritmia em 25% e taquicardia ventricular (TV) não-sustentada ou sustentada em 57%. Ocorreram 18 óbitos, 7 por morte cardíaca súbita, 3 por bradiarritmias, 1 por fibrilação ventricular, 1 por infarto do miocárdio e 2 óbitos devido à causas desconhecidas. A presença de QTc longo (Razão de Probabilidade [RP] = 7,28; intervalo de confiança de 95% [IC] 2,01-26,35; p = 0,002) e duração do intervalo PR (RP = 1,05; IC 95%: 1,02-1,08; p < 0,001) foram associados independentemente a bradiarritmias. A dilatação ventricular esquerda (DVE) foi independentemente associada à TV não-sustentada (RP = 2,83; IC 95%: 1,01-7,96; p = 0,041).Conclusões:Em acompanhamento de médio prazo de CTR, o ILR detectou uma alta incidência de EA, a maioria sem relevância clínica. O intervalo PR e a presença de QTc longo foram preditivos de bradiarritmias e DVE de TV não‑sustentada.

AbstractBackground:The recording of arrhythmic events (AE) in renal transplant candidates (RTCs) undergoing dialysis is limited by conventional electrocardiography. However, continuous cardiac rhythm monitoring seems to be more appropriate due to automatic detection of arrhythmia, but this method has not been used.Objective:We aimed to investigate the incidence and predictors of AE in RTCs using an implantable loop recorder (ILR).Methods:A prospective observational study conducted from June 2009 to January 2011 included 100 consecutive ambulatory RTCs who underwent ILR and were followed-up for at least 1 year. Multivariate logistic regression was applied to define predictors of AE.Results:During a mean follow-up of 424 ± 127 days, AE could be detected in 98% of patients, and 92% had more than one type of arrhythmia, with most considered potentially not serious. Sustained atrial tachycardia and atrial fibrillation occurred in 7% and 13% of patients, respectively, and bradyarrhythmia and non-sustained or sustained ventricular tachycardia (VT) occurred in 25% and 57%, respectively. There were 18 deaths, of which 7 were sudden cardiac events: 3 bradyarrhythmias, 1 ventricular fibrillation, 1 myocardial infarction, and 2 undetermined. The presence of a long QTc (odds ratio [OR] = 7.28; 95% confidence interval [CI], 2.01–26.35; p = 0.002), and the duration of the PR interval (OR = 1.05; 95% CI, 1.02–1.08; p < 0.001) were independently associated with bradyarrhythmias. Left ventricular dilatation (LVD) was independently associated with non-sustained VT (OR = 2.83; 95% CI, 1.01–7.96; p = 0.041).Conclusions:In medium-term follow-up of RTCs, ILR helped detect a high incidence of AE, most of which did not have clinical relevance. The PR interval and presence of long QTc were predictive of bradyarrhythmias, whereas LVD was predictive of non-sustained VT.

FUNDAMENTO: A programação ideal da energia de choque do CDI deve ser pelo menos 10 J acima do limiar de desfibrilação (LDF), necessitando de técnicas alternativas quando o LDF é elevado. OBJETIVO: Avaliar o comportamento clínico dos portadores de CDI com LDF>25 J e a eficácia da terapêutica escolhida. MÉTODOS: Foram selecionados portadores de CDI, entre janeiro de 2000 e agosto de 2004 (banco de dados prospectivo), com LDF>25 J intra-operatório, e analisaram-se: características clínicas, FEVE, resgate de eventos arrítmicos pelo CDI e óbitos. RESULTADOS: dentre 476 pacientes, 16 (3,36%) apresentaram LDF>25J. Idade média de 56,5 anos, sendo 13 pacientes (81%) do sexo masculino. Quanto à cardiopatia de base 09 eram chagásicos, 04 isquêmicos e 03 com etiologia idiopática. A FEVE média dos pacientes foi 37% e 94% utilizavam amiodarona. O seguimento médio foi de 25,3 meses. Em 02 pacientes com LDF > Choque Máximo (CM), foi necessário implante de eletrodo de choque adicional (array), sendo mantido programação com CM em zona de FV (>182bpm) nos demais. Durante o seguimento 03 pacientes apresentaram 67 terapias de choque apropriadas (TCA) com sucesso. Ocorreram 07 óbitos sendo 5 por causas não cardíacas e 2 por insuficiência cardíaca avançada. Os pacientes que foram a óbito apresentaram níveis de LDF maiores (p=0,0446), entretanto sem relação com a causa dos mesmos tendo em vista que não ocorreram TCA sem sucesso. CONCLUSÃO: Nessa coorte de pacientes com CDI, a ocorrência de LDF elevado foi baixa, implicando terapêuticas alternativas. Houve associação com disfunção ventricular grave, entretanto sem correlação com as causas de óbito.

BACKGROUND: The ideal programming of the implantable cardioverter defibrillator (ICD) shock energy should be at least 10J above the defibrillation threshold (DFT), requiring alternative techniques when the DFT is elevated. OBJECTIVE: To assess the clinical behavior of ICD patients with DFT>25J and the efficacy of the chosen therapy. METHODS: Patients who had undergone ICD implantation between Jan/00 and Aug/04 (prospective database) and presented intraoperative DFT>25J were selected. The analyzed variables were: clinical characteristics, LVEF, rescue of arrhythmic events from ICD and causes of deaths. RESULTS: among 476 patients, 16 (3.36%) presented DFT>25J. The mean age was 56.5 years, and 13 patients (81%) were men. According to the baseline cardiomyopathy, 09 patients had Chagas' disease, 04 had ischemic cardiomyopathy and 03 had idiopathic cardiomyopathy. Mean LVEF was 0.37 and amiodarone was used by 94% of the patients. Mean follow-up (FU) period was 25.3 months. DFT was higher than maximum energy shock (MES) in 2 patients and it was necessary to implant an additional shock electrode (array). It was programmed MES in ventricular fibrillation zone of ICD therapy in the other patients. In the FU, 03 patients had 67 successful appropriate shock therapies (AST). There were 05 noncardiac and 02 heart failure deaths. The patients who died showed higher DFT levels (p=0.044) without correlation with death because there wasn't unsuccessful AST. CONCLUSION: In this cohort of ICD patients, the occurrence of elevated DFT (>25J) was low, leading to alternative therapies. There was an association with severe ventricular dysfunction, although without correlation to the causes of death.

OBJECTIVE: To assess the incidence of problems requiring reprogramming of atrioventricular pacemakers in a long-term follow-up, and also the causes for this procedure. METHODS: During the period from May '98 to December '99, 657 patients were retrospectively studied, An actuarial curve for the event reprogramming of the stimulation mode was drawn. RESULTS: The follow-up period ranged from 12 to 178 months (mean = 81 months). Eighty-two (12.4%) patients underwent reprogramming of the stimulation mode as follows: 63 (9.5%) changed to VVI,(R/C); 10 (1.5%) changed to DVI,C; 6 (0.9%) changed to VDD,C; and 3 (0.5%) changed to DOO. The causes for the reprogramming were as follows: arrhythmia conducted by the pacemaker in 39 (37.6%) patients; loss of atrial sensitivity or capture, or both, in 39 (38.6%) patients; and microfracture of atrial electrode in 5 (4.9%) patients. The stimulation mode reprogramming free probability after 15 years was 58%. CONCLUSION: In a long-term follow-up, the atrioventricular pacemaker provided a low incidence of complications, a high probability of permanence in the DDD,C mode, and the most common cause of reprogramming was arrhythmia conducted by the pacemaker.