O ecocardiograma na terapia de ressincronização cardíaca / Echocardiography in cardiac resynchronization therapy

A terapia de ressincronização cardíaca (TRC) tem sido uma opção efetiva nos pacientes com insuficiência cardíaca avançada. No entanto 20 por cento a 30 por cento dos pacientes não apresentam benefícios nessa terapêutica. Critérios clínicos, eletrocardiográficos e ecocardiográficos têm sido estudados na tentativa de selecionar os pacientes que serão beneficiados com a ressincronização cardíaca, mas o ecocardiograma tem papel importante tanto na seleção quanto na avaliação e otimização dessa terapêutica. O objetivo desta revisão é descrever os principais parâmetros ecocardiográficos utilizados na avaliação da terapia de ressincronização cardíaca.

Cardiac resynchronization therapy has been an effective option in patients with advanced heart failure. However, 20 to 30 percent of the patients do not benefit from this therapy. Clinical, electrocardiographic and echocardiographic criteria have been studied in an attempt to select patients who will benefit from a cardiac resynchronization therapy, and the echocardiogram is important both in the selection and in the evaluation and optimization of the therapy. The objective of this review is to describe the main echocardiographic parameters used in the evaluation of the cardiac resynchronization therapy.

Ressincronização ventricular: comparando os marcapassos biventriculares com os marcapassos bifocais de ventrículo direito / Ventricular resynchronization: comparing biventricular and bifocal right ventricular pacemakers

OBJETIVO: Realizar uma análise da estimulação biventricular convencional (BV), da estimulação bifocal (BF) de ventrículo direito (VD) e uma análise comparativa das duas técnicas, em relação aos parâmetros clínicos, funcionais e ecocardiográficos, em uma população sem os critérios de exclusão dos trabalhos clássicos. MÉTODOS: Foram analisados de forma prospectiva, não randomizada, 36 pacientes submetidos a cirurgia para implantes de marcapassos multissítos devido a QRS > 130 ms, disfunção ventricular esquerda grave e insuficiência cardíaca congestiva classe funcional III ou IV. RESULTADOS: Os resultados favoráveis da ressincronização foram obtidos com as duas técnicas, sem diferenças significativas na comparação dos dois grupos, exceto por maior estreitamento do QRS e tendência a menor número de internações no grupo dos BV. Quando os grupos foram analisados individualmente e comparados, antes e após os procedimentos, observamos que as melhoras foram bem mais expressivas no grupo dos biventriculares, assim como os índices de relevância estatística maiores. CONCLUSÃO: A terapia de ressincronização cardíaca mostrou ser terapia eficaz nos 2 grupos analisados, entretanto com resultados mais expressivos no grupo dos biventriculares.

OBJECTIVE:To analyze the conventional biventricular pacing (BV) and the bifocal (BF) right ventricular (RV) pacing, and to perform a comparative analysis of these two techniques in relation to clinical, functional and echocardiographic parameters in a population without the exclusion criteria of the major studies. METHODS:A prospective non-randomized analysis of 36 patients undergoing surgery for multisite pacemaker implantation due to QRS > 130 ms, severe left ventricular dysfunction, and NYHA functional class III or ambulatory class IV congestive heart failure was performed. RESULTS: Favorable results of resynchronization were obtained with both techniques, with no significant differences in the comparison of the two groups, except for a higher QRS narrowing in the BV group, and a trend of a lower number or hospital admissions in the BV group. When the groups were analyzed separately and compared before and after the procedures, we observed that improvement was much more significant in the biventricular group, as were the more statistically relevant rates. CONCLUSION: Cardiac resynchronization therapy proved to be an efficient therapy in both groups analyzed, although with more significant outcomes in the biventricular group.

Utilidad de los marcapasos: análisis de la estimulación cardiaca definitiva, experiencia Julio 1996 - junio 2003 / Utility of the marcapasos: analysis of the definitive stimulation cardiac, experience Julio 1996 - June 2003

El presente articulo pretende actualizar las indicaciones y las características técnicas básicas de los principales tipos de marcapasos, a propósito de la experiencia en el implante de los mismos. Con este fin se revisaron los expedientes de implantes de marcapasos elfectuados en el periodo Julio de 1996 a junio del 2003, en el Instituto Nacioal de Tórax. Se hace especial énfasis en la técnica quirúrgica. Las indicaciones más frecuentes para implante de marcapasos en la serie estudiada fueron la cardioesclerosis (61 porciento) y la cardiopatía chagásica (33 por ciento). La alteraión electrocardiográfica principal pre-implante fue el bloqueo auriculoventriclar completo /57 por ciento). La técnica habitual consistió en la disección venosa. La gran mayoría de los marcapsos implantados fueron del tipo VVI (86 por ciento). Los resultados son buenos con un mínimo índice de complicaciones.

Heart failure: what proportion of patients satisfy the electrocardiographic criteria for cardiac resynchronization therapy?

BACKGROUND: Cardiac resynchronization therapy has emerged as a new therapeutic modality for patients with congestive cardiac failure and associated intraventricular conduction delay. The purpose of this study was to find out what proportion of Indian patients with congestive heart failure may be candidates for cardiac resynchronization therapy based on electrocardiographic characteristics. METHODS AND RESULTS: One hundred twenty-one consecutive patients with congestive cardiac failure due to various etiologies whose left ventricular ejection fraction was less than 40% were included in the study. Standard 12-lead electrocardiogram was recorded in all the patients, and various parameters (rhythm, conduction, QRS axis, chamber enlargement, chamber hypertrophy, and the presence of Q waves) were analyzed. The study population comprised 82 male (67.8%) and 39 female (32.2%) patients with a mean age of 53 +/- 13 years. Thirty-nine patients (32.2%) had NYHA class I-II symptoms, and 82 (67.8%) had NYHA class III-IV symptoms. The mean QRS duration was 111 +/- 27 ms. Bundle branch block was seen in 43 patients (35.5%), of whom 30 (24.8%) had left bundle branch block, and 13 (10.7%) had right bundle branch block. Of the 30 patients who had left bundle branch block, 19 (15.7%) had a QRS duration of between 120 and 149 ms, and 11 (9%) had a QRS duration > or = 150 ms. In the latter group, 7 patients (5.8%) were in NYHA classes III and IV. As the clinical severity of heart failure increased, the mean QRS duration also increased, but this increment was not statistically significant. CONCLUSIONS: Based on our data, it can be estimated that of the patients with heart failure who attend a tertiary care center, 2 5% of patients present with left bundle branch block. If we use the criteria for NYHA class III and IV congestive cardiac failure with QRS duration of > or = 150 ms in patients with left bundle branch block, 6% of patients are likely to need cardiac resynchronization therapy.