Mortality risk score for patients with Chagas cardiomyopathy and pacemaker.

BACKGROUND: Prognosis of Chronic Chagasic Cardiomyopathy (CCC) patients depends on functional and clinical factors. Bradyarrhythmia requiring pacemaker is a common complication. Prognosis of these patients is poorly studied, and mortality risk factors are unknown. We aimed to identify predictors of death and to define a risk score for mortality in a large cohort of CCC patients with pacemaker. METHODS: It was an observational, unicentric and prospective study. The endpoint was all-cause mortality. Cox regression was used to identify predictors of death and to define a risk score. Bootstrapping method was used to internal score validation. RESULTS: We included 555 patients and after a mean follow-up of 3.7±1.5 years, 100 (18%) deaths occurred. Predictors of death were: right ventricular dysfunction (HR [hazard ratio] 2.24; 95%CI 1.41-3.53; P = 0.001); heart failure class III or IV (HR 2.16; 95% confidence interval [95%CI] 1.16-4.00; P = 0.014); renal disease (HR 2.14; 95%CI 1.24-3.68; P = 0.006); left ventricular end-systolic diameter > 44mm (HR 1.97; 95%CI 1.26-3.05; P = 0.003); atrial fibrillation (HR 1.94; 95%CI 1.25-2.99; P = 0.003) and cardiomegaly on X-ray (HR 1.87; 95%CI 1.10-3.17; P = 0.020). The score identified patients with: low (0-20 points), intermediate (21-30 points) and high risk (>31points). The optimism-corrected C-statistic of the predictive model was 0.751 (95% CI 0.696-0.806). Internal validation with bootstrapping revealed a calibration slope of 0.946 (95% CI 0.920-0.961), reflecting a small degree of over-optimism and C-statistic of 0.746 (95% CI 0.692-0.785). CONCLUSIONS: This study identified predictors of mortality in CCC patients with pacemaker defining a simple, validated and specific risk score.

Síndrome de Kearns Sayre - relato de caso / Kearns Sayre Syndrome - case report

A Síndrome de Kearns Sayre (SKS) é uma miopatia de origem mitocondrial rara. Caracterizase pela tríade de oftalmoplegia externa, retinose pigmentar e acometimento do sistema de condução cardíaco, descrita em 1958. O objetivo deste relato de caso é descrever um caso de SKS e discutir achados clínicos com ênfase no acometimento cardíaco. Paciente J.A., masculino, 35 anos, com sintomas iniciais de diplopia, estrabismo e ptose. Evoluiu com alteração da motricidade ocular extrínseca, retinopatia pigmentosa e fraqueza muscular difusa o que levou à hipótese de SKS. O diagnóstico definitivo foi feito através de biópsia do bíceps que revelou padrão miopático mitocondrial. Em seguida, encaminhado para investigação de distúrbio de condução. Em primeira consulta evidenciado eletrocardiograma com ritmo sinusal, BAV 1° grau, bloqueio de ramo esquerdo, pausa sinusal e ritmo juncional de 40 bpm. Ecocardiograma com FE 62% e contratilidade preservada. Indicado implante de marcapasso (MP) atrioventricular. Atualmente, com necessidade de 100% de pacing ventricular sem escape ventricular e fibrilação atrial paroxística em anticoagulação. Desde então, segue em acompanhamento ambulatorial. A SKS é uma doença genética relacionada a mutação do DNA mitocondrial. As mitocôndrias são responsáveis pela produção de ATP e fornecimento de energia para diversas funções metabólicas. Por isso, tecidos com alto gasto energético, são os mais acometidos em tais anomalias genéticas. As manifestações cardiológicas ocorrem em 57% dos casos. As alterações eletrocardiográficas mais comuns são bloqueio divisional anterossuperior e bloqueio de ramo direito. Tipicamente ocorre progressão para bloqueio atrioventricular avançado. Morte súbita está associada em até 20% dos casos. A Sociedade Europeia, em sua diretriz de estimulação cardíaca artificial 2021, orienta implante de MP diante do achado de prolongamento de intervalo PR e evidência de bloqueio atrioventricular de qualquer grau, bloqueio de ramo ou bloqueio fascicular. A SKS é uma doença incomum e com repercussão clínica importante. Se negligenciada, o acometimento cardíaco é potencialmente fatal. Assim, cabe ao cardiologista estar atento ao momento ideal de indicação de MP.

Effect of chronic kidney disease in ischemic cardiomyopathy: Long-term follow-up - REVISION-DM2 trial.

A strong association exists between chronic kidney disease (CKD) and coronary artery disease (CAD). The role of CKD in the long-term prognosis of CAD patients with versus those without CKD is unknown. This study investigated whether CKD affects ventricular function.From January 2009 to January 2010, 918 consecutive patients were selected from an outpatient database. Patients had undergone percutaneous, surgical, or clinical treatment and were followed until May 2015.In patients with preserved renal function (n = 405), 73 events (18%) occurred, but 108 events (21.1%) occurred among those with CKD (n = 513) (P < .001). Regarding left ventricular ejection fraction (LVEF) <50%, we found 84 events (21.5%) in CKD patients and 12 (11.8%) in those with preserved renal function (P < .001). The presence of LVEF <50% brought about a modification effect. Death occurred in 22 (5.4%) patients with preserved renal function and in 73 (14.2%) with CKD (P < .001). In subjects with LVEF <50%, 66 deaths (16.9%) occurred in CKD patients and 7 (6.9%) in those with preserved renal function (P = .001). No differences were found in CKD strata regarding events or overall death among those with preserved LVEF. In a multivariate model, creatinine clearance remained an independent predictor of death (P < .001).We found no deleterious effects of CKD in patients with CAD when ventricular function was preserved. However, there was a worse prognosis in patients with CKD and ventricular dysfunction.Resgistry number is ISRCTN17786790 at https://doi.org/10.1186/ISRCTN17786790.

A cohort study of cardiac resynchronization therapy in patients with chronic Chagas cardiomyopathy.

Aims: Cardiac resynchronization therapy (CRT) is an established procedure for patients with heart failure. However, trials evaluating its efficacy did not include patients with chronic Chagas cardiomyopathy (CCC). We aimed to assess the role of CRT in a cohort of patients with CCC. Methods and results: This retrospective study compared the outcomes of CCC patients who underwent CRT with those of dilated (DCM) and ischaemic cardiomyopathies (ICM). The primary endpoint was all-cause mortality and the secondary endpoints were the rate of non-advanced New York Heart Association (NYHA) class 12 months after CRT and echocardiographic changes evaluated at least 6 months after CRT. There were 115 patients in the CCC group, 177 with DCM, and 134 with ICM. The annual mortality rates were 25.4%, 10.4%, and 11.3%, respectively (P < 0.001). Multivariate analysis adjusted for potential confounders showed that the CCC group had a two-fold [hazard ratio 2.34 (1.47-3.71), P < 0.001] higher risk of death compared to the DCM group. The rate of non-advanced NYHA class 12 months after CRT was significantly higher in non-CCC groups than in the CCC group (DCM 74.0% vs. ICM 73.9% vs. 56.5%, P < 0.001). Chronic Chagas cardiomyopathy and ICM patients had no improvement in the echocardiographic evaluation, but patients in the DCM group had an increase in left ventricular ejection fraction and a decrease in left ventricular end-diastolic diameter. Conclusion: This study showed that CCC patients submitted to CRT have worse prognosis compared to patients with DCM and ICM who undergo CRT. Studies comparing CCC patients with and without CRT are warranted.

Predictors of death in chronic Chagas cardiomyopathy patients with pacemaker.

BACKGROUND: Chronic Chagas cardiomyopathy (CCC) is the most serious and frequent manifestation of Chagas disease. Conduction abnormalities and bradycardia requiring pacemaker are common. The aim of this study was to determine the rate and predictors of death in CCC patients with pacemaker. METHODS: In this single-center prospective cohort study we assessed the outcome of 396 CCC patients with pacemaker, followed-up for at least 24months. All patients underwent a clinical and device assessment, 12-lead electrocardiography and echocardiography. RESULTS: During the median follow-up of 1.9years (Interquartile range 1.6-2.4), there were 65 (16.4%) deaths, yielding an annual mortality rate of 8.6%. The major cause was sudden death (33.8%), followed by heart failure (HF), 32.3%. All the investigated variables were examined as potential predictors of death. The final multivariate logistic regression model included five independent variables: advanced HF functional class (OR [odds ratio] 6.71; 95% confidence interval [95% CI] 1.95-23.2; P=0.003), renal disease (OR 5.71; 95% CI 1.80-18.0; P=0.003), QRS ≥150ms (OR 2.80; 95% CI 1.08-7.27; P=0.034), left atrial enlargement (OR 2.75; 95% CI 1.09-6.95; P=0.032) and left ventricular ejection fraction ≤43% (OR 2.31; 95% CI 1.07-4.97; P=0.032). The model had good discrimination, confirmed by bootstrap validation (optimism-adjusted c-statistic of 0.78) and the calibration curve showed a proper calibration (slope=0.972). CONCLUSIONS: CCC patients with pacemaker have a high annual mortality rate despite that the pacemaker related variables were not predictors of death. The independent predictors of death can help us to identify the poor prognosis patients.

Terapia de ressincronização cardíaca na cardiomiopatia chagásicacrônica: boa resposta clínica e pior prognóstico / Cardiac resynchronization therapy in chronic chagasic cardiomyopathy: a good clinical response and the worst prognosis

Os efeitos da terapia de ressincronização cardíaca (TRC) em pacientes com cardiomiopatiaisquêmica (CMI) e dilatada (CMD) são bem conhecidos. Entretanto, faltam evidências científicas da TRC nacardiomiopatia chagásica crônica (CCC). Objetivo: avaliar o comportamento clínico de pacientes submetidos àTRC, considerando a importância da CCC. Método: no período de janeiro de 2005 a dezembro de 2007 foramincluídos 343 pacientes em seguimento clínico na Unidade de Estimulação Cardíaca do Instituto do Coração,submetidos a intervenção cirúrgica relacionada à TRC. A análise estatística de previsores de mortalidade foirealizada por regressão logística com seleção stepwise, incluindo variáveis com p<0,1 na análise univariada. Asvariáveis estudadas foram: idade, gênero, classe funcional (CF) da New York Heart Association, cardiopatia, tipode bloqueio de ramo, parâmetros ecocardiográficos, medicações em uso e óbito. Resultados: foram selecionados343 pacientes, 65% do sexo masculino, com idade média de 59,7 ± 12,3 anos e seguimento médio de 4,2 ± 2,7anos após a TRC. A CF pré-implante foi II em 18,3%, III em 64,5% e IV em 17,3%. A fração de ejeção média doventrículo esquerdo foi de 27,66 ± 8,99. A cardiopatia de base distribuiu-se em: CMD em 35%; CMI em 29,4%;CCC em 22,4% e outras etiologias em 13,1%. A taxa de melhora da classe funcional após a TRC foi semelhante,independente da cardiopatia, mas a CCC mostrou pior prognóstico (odds ratio=3,03; IC 95%, 1,15-7,97, p<0,001).Conclusão: pacientes com CCC submetidos à TRC apresentam melhora sintomática, porém o risco de óbito é trêsvezes maior em comparação com as outras cardiopatias.

The effects of cardiac resynchronization therapy (CRT) in patients with ischemic (ICM) and dilated(DCM) cardiomyopathy are known. In chronic chagasic cardiomyopathy (CCC), scientific evidence is lacking.Objective: To evaluate the clinical response of patients undergoing CRT, considering the importance of theCCC. Methods: From January 2005 to December 2007, we included 343 patients in clinical follow-up in CardiacPacing Unit of Heart Institute, who underwent surgery related to CRT. Statistical analysis of mortality predictorswas performed using logistic regression with stepwise selection, including variables with P<0.1 in the univariateanalysis. The variables studied were age, gender, functional class of New York Heart Association, etiology of heartdisease, type of bundle branch block, echocardiographic parameters, medications and death. Results: The studyenrolled 343 patients, 65% male, mean age 59.7 ± 12.3 years, with a mean follow-up after CRT of 4.2 ± 2.7 years. The functional class before implant was II, III and IV in 18.3%, 64.5% and 17.3%, respectively. The mean ejectionfraction of the left ventricle was 27.66 ± 8.99. The underlying heart disease was DMC, ICM, CCC and othercauses in 35%, 29.4%, 22.4% and 13.1%, respectively. The rate of improvement in functional class after CRT wassimilar, independent of heart disease etiology, but the CCC showed the worst prognosis (Odds ratio=3.03; 95%CI 1.15-7.97, P<0.001). Conclusion: Patients with CCC undergoing CRT show symptomatic improvement, butthe risk of death is three times higher, compared with other heart diseases.

Los efectos de la terapia de resincronización cardiaca (TRC) en pacientes con miocardiopatía isquémica(MCI) y dilatada (MCD) son conocidos. En la miocardiopatía chagásica crónica (MCC), sin embargo, faltanevidencias científicas. Objetivo: Evaluar el comportamiento clínico de pacientes sometidos a la TRC, considerándosela importancia de la MCC. Métodos: En el período de enero de 2005 a diciembre de 2007, fueron incluidos 343pacientes en seguimiento clínico en la Unidad de Estimulación Cardiaca del Instituto del Corazón, sometidos ala intervención quirúrgica relacionada a la TRC. El análisis estadístico de predictores de mortalidad fue llevado acabo por regresión logística con selección stepwise, incluyéndose variables con p<0,1 en el análisis univariado. Lasvariables estudiadas fueron: edad, género, clase funcional (CF) de la New York Heart Association, cardiopatía, tipode bloqueo de rama, parámetros ecocardiográficos, fármacos en uso y defunción. Resultados: Fueron seleccionados343 pacientes, el 65% del sexo masculino, edad media de 59,7 ± 12,3 años, con seguimiento medio tras la TRC de4,2 ± 2,7 años. La CF pre implante fue II en el 18,3%, III en el 64,5% y IV en el 17,3%. La fracción de eyección deventrículo izquierdo media fue de 27,66 ± 8,99. La cardiopatía de base se distribuyó en: MCD en el 35%; MCI enel 29,4%; MCC en el 22,4% y otras etiologías en el 13,1%. El índice de mejora de clase funcional tras la TRC fuesemejante, independientemente de la cardiopatía, pero la MCC mostró peor pronóstico (Odds Ratio=3,03 IC95%1,15-7,97, p<0,001). Conclusión: Pacientes con MCC sometidos a la TRC presentan mejora sintomática, sin embargo,riesgo de fallecimiento tres veces mayor, en comparación con las otras cardiopatías.

Papel da medicina nuclear na terapia de ressincronização cardíaca: [revisão] / Role of nuclear medicine in the cardiac resinchronization therapy: [review]

A terapia de ressincronização cardíaca (TRC) surgiu como a mais promissora abordagem no tratamento da dissincronia cardíaca, em pacientes com insuficiência cardíaca refratária ao tratamento medicamentoso. Embora seus resultados clínicos e funcionais sejam de fato promissores, as análises das respostas individuais revelam que uma significativa parcela dos pacientes não responde ao tratamento. Nesta revisão, foi discutido o papel da medicina nuclear e imagem molecular na seleção de candidatos à TRC, por meio do estudo da dissincronia cardíaca, avaliação de viabilidade, perfusão e fluxo sanguíneo miocárdicos e atividade simpática cardíaca. O potencial uso dessa técnica, no aprimoramento da compreensão dos efeitos deletérios da dissincronia, sobre a função cardíaca e na avaliação e monitorização de resposta à TRC, foram também abordados. Outros alvos moleculares que caracterizam metabolismo glicolítico e de ácido graxo, apoptose, atividade da enzima conversora da angiotensina e angiogênese, que podem seravaliados e medidos por essa técnica, foram descritos.

Cardiac resynchronization therapy (CRT) emerged as one of the most promising approaches in the treatment of cardiac dyssynchrony in heart failure patients’ refractory to medical treatment. However, despite very promising clinical and functional results, individual response analyses show that a significant number of patients do not respond to treatment. The role of nuclear medicine and molecular imaging in the selection of CRT candidates by the assessment of cardiac dyssynchrony, myocardial viability, myocardial perfusion and blood flow and sympathetic cardiac activity has been discussed in this review. The potential utilization of this tool to improve the comprehension of detrimental effects of dyssynchrony on cardiac function and the evaluation and monitoring of the response to CRT were also considered. Other molecular targets that characterize glucose and fatty acid metabolism, apoptosis, angiotensin converting enzyme activity and angiogenesis that can be evaluated with this technique were described.

"Hyper-response" evaluated by 3D echocardiography after cardiac resynchronization therapy.

Cardiac resynchronization therapy consists of a promising treatment for patients with severe heart failure, but about 30% of patients do not exhibit clinical improvement with this procedure. However, approximately 10% of patients undergoing this therapy may have hyperresponsiveness, and three-dimensional echocardiography can provide an interesting option for the selection and evaluation of such patients.

"Hiper-resposta" avaliada pelo eco 3D após terapia de ressincronização cardíaca / "Hyper-response" evaluated by 3D echocardiography after cardiac resynchronization therapy / "Hiperrespuesta" evaluada por el eco 3D después de la terapia de resincronización cardíaca

A terapia de ressincronização cardíaca consiste em tratamento promissor para pacientes com insuficiência cardíaca grave, porém cerca de 30 por cento dos pacientes não apresentam melhora clínica com este tratamento. Por outro lado, aproximadamente 10 por cento dos pacientes submetidos a essa terapia podem apresentar hiper resposta, e a ecocardiografia tridimensional pode oferecer uma opção interessante para a seleção e avaliação de tratamento desses pacientes.

Cardiac resynchronization therapy consists of a promising treatment for patients with severe heart failure, but about 30 percent of patients do not exhibit clinical improvement with this procedure. However, approximately 10 percent of patients undergoing this therapy may have hyperresponsiveness, and three-dimensional echocardiography can provide an interesting option for the selection and evaluation of such patients.

La terapia de resincronización cardíaca consiste en un tratamiento promisorio para pacientes con insuficiencia cardíaca grave, sin embargo cerca de un 30 por ciento de los pacientes, no presentan una mejoría clínica con ese tratamiento. Por otro lado, aproximadamente un 10 por ciento de los pacientes sometidos a esa terapia pueden presentar hiperrespuesta, y la ecocardiografía tridimensional puede ser una opción interesante para la selección y la evaluación del tratamiento de esos pacientes.

Efficacy of antibiotic prophylaxis before the implantation of pacemakers and cardioverter-defibrillators: results of a large, prospective, randomized, double-blinded, placebo-controlled trial.

BACKGROUND: Although routinely administered, definitive evidence for the benefits of prophylactic antibiotics before the implantation of permanent pacemakers and implantable cardioverter-defibrillators from a large double-blinded placebo-controlled trial is lacking. The purpose of this study was to determine whether prophylactic antibiotic administration reduces the incidence of infection related to device implantation. METHODS AND RESULTS: This double blinded study included 1000 consecutive patients who presented for primary device (Pacemaker and implantable cardioverter-defibrillators) implantation or generator replacement randomized in a 1:1 fashion to prophylactic antibiotics or placebo. Intravenous administration of 1 g of cefazolin (group I) or placebo (group 2) was done immediately before the procedure. Follow-up was performed 10 days, 1, 3, and 6 months after discharge. The primary end point was any evidence of infection at the surgical incision (pulse generator pocket), or systemic infection related to be procedure. The safety committee interrupted the trial after 649 patients were enrolled due to a significant difference in favor of the antibiotic arm (group I: 2 of 314 infected patients-0.63%; group II: 11 of 335 to 3.28%; RR=0.19; P=0.016). The following risk factors were positively correlated with infection by univariate analysis: nonuse of preventive antibiotic (P=0.016); implant procedures (versus generator replacement: P=0.02); presence of postoperative hematoma (P=0.03) and procedure duration (P=0.009). Multivariable analysis identified nonuse of antibiotic (P=0.037) and postoperative hematoma (P=0.023) as independent predictors of infection. CONCLUSIONS: Antibiotic prophylaxis significantly reduces infectious complications in patients undergoing implantation of pacemakers or cardioverter-defibrillators.

Functional behavior of patients with conventional pacemakers undergoing cardiac resynchronization.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an efficient treatment for patients with heart failure (HF), severe ventricular dysfunction and intraventricular block. Conventional pacemakers (CPM) implanted in the right ventricular apical area cause alterations in the normal sequence of cardiac activation similar to those induced by LBBB (left bundle-branch block). Therefore, patients with CPM and advanced HF could be candidates to undergo CRT, but as only small numbers of patients have been evaluated so far, definitive conclusions are lacking. OBJECTIVE: To assess the clinical and functional outcome of cardiac resynchronization therapy (CRT) in patients with conventional pacemakers. METHODS: Patients with CPM, who were in NYHA HF functional class III/IV class refractory to drug therapy, and left ventricular ejection fraction (LVEF) ) <35% underwent CRT. Patients clinical-functional behavior was assessed prospectively six months after the procedure. The improvement of one HF-functional class was set as an effective response to the procedure. The following was assessed: QRS duration (ECG), diastolic diameter (LVDd), left ventricular systolic diameter (LVSd) and LVEF seen on the echocardiogram. For the statistical analysis, Students paired t test and Spearmans correlation were used. RESULTS: Twenty-nine patients (mean age 61.5) were evaluated. Of these, six were females, and chagasic cardiomyopathy was predominant. During the clinical follow-up of 22.7+/-13 months, 86.2% of the patients benefited from CRT. Within this group, the mean LVEF increased by 18% (p=0.013), QRS duration dropped by 11.8% (p=0.002) and no significant reduction in left ventricular intracavitary diameters was observed. CONCLUSION: CRT is effective for patients with CPM and advanced HF as it yields a high rate of response (86.2%), significantly improves LVEF and reduces QRS duration.

ICD patients with elevated defibrillation threshold: clinical behavior and therapeutic alternatives.

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.

Portadores de CDI com limiar de desfibrilação elevado: evolução clínica e alternativas terapêuticas / ICD patients with elevated defibrillation threshold: clinical behavior and therapeutic alternatives

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 por cento) apresentaram LDF>25J. Idade média de 56,5 anos, sendo 13 pacientes (81 por cento) 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 por cento e 94 por cento 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 percent) presented DFT>25J. The mean age was 56.5 years, and 13 patients (81 percent) 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 percent 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.

Comportamento funcional dos portadores de marcapasso convencional submetidos a ressincronização cardíaca / Functional behavior of patients with conventional pacemakers undergoing cardiac resynchronization

FUNDAMENTO: A terapia de ressincronização cardíaca (TRC) é eficiente no tratamento de pacientes com insuficiência cardíaca (IC), disfunção ventricular grave e bloqueio intraventricular. O marcapasso convencional (MPC) em região apical de ventrículo direito provoca alterações da seqüência de ativação normal do coração semelhante às do BRE. Nesse sentido, pacientes com MPC e IC avançada poderiam ser candidatos a TRC, mas reduzidas casuísticas foram avaliadas e não há conclusões definitivas. OBJETIVO: Analisar o comportamento clínico-funcional da terapia de ressincronização cardíaca (TRC) nos portadores de marcapasso convencional. MÉTODOS: Pacientes com MPC, IC-CF(NYHA) III/IV refratária a terapêutica medicamentosa, fração de ejeção do ventrículo esquerdo (FEVE) <35 por cento, foram submetidos a TRC. O comportamento clínico-funcional foi avaliado prospectivamente após seis meses. A redução de uma CF-IC foi estabelecida como resposta efetiva ao procedimento. Foram analisados: duração do QRS (ECG), diâmetro diastólico (DDVE), diâmetro sistólico do ventrículo esquerdo (DSVE) e FEVE ao ECO. A análise estatística utilizou os testes t de Student pareado e a correlação de Spearman. RESULTADOS: Vinte e nove pacientes com idade média de 61,5 anos foram estudados. Seis eram do sexo feminino e houve predomínio da cardiomiopatia chagásica. Em seguimento clínico de 22,7±13 meses, 86,2 por cento dos pacientes melhoraram com a TRC. Nesse grupo, a FEVE média aumentou em 18 por cento (p=0,013); houve redução da duração do QRS em 11,8 por cento (p=0,002) e não houve redução significativa dos diâmetros intracavitários do ventrículo esquerdo. CONCLUSÃO: A TRC é efetiva para pacientes com MPC e IC avançada porque proporciona taxa elevada de responsivos (86,2 por cento), melhora significativa da FEVE e redução da duração do QRS.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an efficient treatment for patients with heart failure (HF), severe ventricular dysfunction and intraventricular block. Conventional pacemakers (CPM) implanted in the right ventricular apical area cause alterations in the normal sequence of cardiac activation similar to those induced by LBBB (left bundle-branch block). Therefore, patients with CPM and advanced HF could be candidates to undergo CRT, but as only small numbers of patients have been evaluated so far, definitive conclusions are lacking. OBJECTIVE: To assess the clinical and functional outcome of cardiac resynchronization therapy (CRT) in patients with conventional pacemakers. METHODS: Patients with CPM, who were in NYHA HF functional class III/IV class refractory to drug therapy, and left ventricular ejection fraction (LVEF) ) <35 percent underwent CRT. Patients’ clinical-functional behavior was assessed prospectively six months after the procedure. The improvement of one HF-functional class was set as an effective response to the procedure. The following was assessed: QRS duration (ECG), diastolic diameter (LVDd), left ventricular systolic diameter (LVSd) and LVEF seen on the echocardiogram. For the statistical analysis, Student’s paired t test and Spearman’s correlation were used. RESULTS: Twenty-nine patients (mean age 61.5) were evaluated. Of these, six were females, and chagasic cardiomyopathy was predominant. During the clinical follow-up of 22.7±13 months, 86.2 percent of the patients benefited from CRT. Within this group, the mean LVEF increased by 18 percent (p=0.013), QRS duration dropped by 11.8 percent (p=0.002) and no significant reduction in left ventricular intracavitary diameters was observed. CONCLUSION: CRT is effective for patients with CPM and advanced HF as it yields a high rate of response (86.2 percent), significantly improves LVEF and reduces QRS duration.

Incidence of shock and quality of life in young patients with implantable cardioverter-defibrillator.

OBJECTIVES: To analyze the incidence and causes of ICD therapies in children and young adults and verify their impact on the quality of life (QoL). METHODS: From March/1977 to February/2006, 29 patients (15.7+/-5.4 years old) were submitted to ICD implants. Aborted cardiac arrest (41.5%), sustained ventricular tachycardia (27.6%) and primary prophylaxis of sudden cardiac death (30.9%) indicated device therapy. The number of therapies was evaluated by interviewing patients and by ICD diagnostic data. The SF-36 questionnaire was used to measure the QoL and the results were compared to healthy population. The expectative of freedom from ICD therapies were estimated by the Kaplan-Meier method. RESULTS: After 2.6+/-1.8 years follow-up, 8 (27.6%) patients received 141 appropriate ICD shocks due to ventricular tachycardia (6) or ventricular fibrillation (2), and 11 (37.9%) patients received 152 inappropriate ICD shocks due to supraventricular tachyarrhythmias (8) or oversensing (3). Expectative of freedom from appropriate shocks was 74.2+/-9.0% and 66.7+/-10.7% after one and three years, respectively. Compared to healthy population, QoL decreased in physical function (61.7+/-28.7), vitality (64.7+/-19.1), mental health (65.9+/-22.7) and role-emotional domains (66.7+/-38.5). All patients referred fear and concern related to ICD use. CONCLUSION: Despite the efficacy of ICD therapies, the high incidence of appropriate and inappropriate shocks interfered in patients QoL and adaptation to the device.

Ventricular remodeling in right ventricular apical pacing.

OBJECTIVE: To determine ventricular remodeling (VR) and the role of clinical and functional variables in patients with normal cardiac function who underwent right ventricular apical pacing (RVAP). METHODS: Among the 268 consecutive patients with standard pacemaker due to complete atrioventricular block (CAVB), those with left ventricular ejection fraction (LVEF) < 55% and left ventricular end-diastolic diameter (LVEDD) > 53 mm on Doppler echocardiography were excluded. Ventricular remodeling was defined as echocardiographic changes documented at least six months after implantation, namely, a >10% increase in LVEDD and a > 20% decrease in LVEF. The following variables were analyzed: underlying heart disease, NYHA functional class of heart failure (HF), time of ventricular stimulation, and QRS duration. Statistical analysis included likelihood ratio test, Fishers exact test, and Wilcoxon rank-sum test. A p value < 0.05 was considered statistically significant. RESULTS: The study included 75 patients, mean age 70.9 +/- 14, of whom 22.6% were male. Mean time between both evaluations was 80.2 months. Before implantation, mean LVEF was 72% and LVEDD was 46 mm; after implantation this values were 69.7% (p = 0.0025) and 48.5 mm (p = 0.0001), respectively. Mean QRS duration after implantation was 156 ms. Ventricular remodeling was observed only in four patients (5.3%), and no exploratory variable specified this behavior. CONCLUSION: In a long-term follow-up, patients without ventricular dysfunction who underwent RV apical pacing (RVAP) showed low VR rate, and no analyzed variable was associated with its occurrence.