Evaluación del Compromiso Cardiovascular en niños en diálisis mediante el Índice de Masa Ventricular Izquierdo / Left Ventricular Mass Index and Cardiovascular Compromise in children on dialysis

INTRODUCCIÓN: Existe una estrecha relación entre enfermedad renal crónica (ERC) y enfermedad cardiovascular. Una de sus manifestaciones clínicas es la hipertrofia de ventrículo izquierdo (HVI), expresada como Indice de Masa Ventricular Izquierda (IMVI, gr/m27). En pacientes portadores de ERC con retraso de creci miento, el cálculo de IMVI debería ajustarse corrigiendo la edad para la talla. OBJETIVO: Comparar el IMVI corregido por edad para la talla, con el valor calculado por edad cronológica en niños con ERC en diálisis. PACIENTES Y MÉTODO: Estudio de corte transversal. Se analizan ecocardiografías de pacientes portadores de ERC en diálisis entre 1-18 años, enero de 2016 a julio 2017. Se evalúa IMVI ajustando el valor expresado a gr/m27 al percentil para la edad cronológica del niño, y luego se ajusta el valor a la edad corregida por la talla. Se usa estadística descriptiva y estudio de concordancia para las evaluacio nes de IMVI calculado por edad cronológica y para edad corregida por talla. RESULTADOS: Se incluyeron 26 pacientes, 75 ecocardiogramas. Un 56% presentó HVI usando IMVI calculado por edad cronoló gica vs un 46,6% al corregir la edad para la talla. Al comparar los grupos de percentiles de IMVI-edad cronológica vs IMVI ajustado a la edad para la talla real, se observó que el 18,6% de la muestra cambia de grupo de percentil, el 100% de ellos a un grupo de percentil inferior. La concordancia evaluada en base a coeficiente Kappa fue de 0,72 (concordancia perfecta > 0,8), confirmando diferencias al ajustar el IMVI para la edad corregida por la talla. CONCLUSIÓN: El cálculo de IMVI por edad cronológica so breestima el compromiso cardiovascular en niños con ERC que característicamente tienen un retraso de talla. Los resultados sugieren que el cálculo de IMVI ajustado a la edad corregida por talla otorga mayor precisión al diagnóstico de hipertrofia ventricular izquierda en este grupo de pacientes.

INTRODUCTION: There is a close relationship between chronic kidney disease (CKD) and cardiovascular disease. One of its clinical manifestations is left ventricular hypertrophy (LVH), expressed as Left Ventricular Mass Index (LVMI gr/m27). In CKD patients with growth retardation, the LVMI calculation should be adjusted by correcting age for length/height. OBJECTIVE: To compare the age-corrected LVMI for length/height with the value calculated by chronological age in CKD children on dialysis. PATIENTS AND METHOD: Cross-sectional study. We analyzed echocardiographies of CKD children on dialysis aged between 1 and 18, from January 2016 to July 2017. LVMI was evaluated by adjusting the value expressed in gr/m27 to the percentile for the chronological child's age, and then the value was adjusted to the age-corrected length/height. We used descriptive statistics and concordance study for LVMI assessments calculating by chronological age and for age-corrected length/height. RESULTS: 26 patients were included and 75 echocardiograms. 56% had left ventricular hypertrophy using chronological age versus 46.6% age-corrected LVMI for length/height. When comparing the percentile groups of LVMI-chronological age vs. age-adjusted LVMI for actual length/height, it was observed that 18.6% of the sample changed percentile groups, 100% of them to a lower percentile group. The agreement evaluated based on the Kappa coefficient was 0.72 (perfect agreement > 0.8), confirming differences when adjusting the LVMI for age-corrected length/height. CONCLUSION: Calculating LVMI by chro nological age overestimates the cardiovascular involvement in children with CKD who are charac teristically stunted. The results suggest that the age-adjusted, length/height-corrected calculation of LVMI gives greater accuracy to the diagnosis of left ventricular hypertrophy in this group of patients.

Reproducibility and Reliability Of QTc and QTcd Measurements and Their Relationships with Left Ventricular Hypertrophy in Hemodialysis Patients / Reprodutibilidade e Confiabilidade das Medidas de QTc e DQTc e suas Relações com a Hipertrofia Ventricular Esquerda em Pacientes em Hemodiálise

Abstract Background: Left ventricular hypertrophy (LVH) is very common in hemodialysis patients and an independent risk factor for mortality in this population. The myocardial remodeling underlying the LVH can affect ventricular repolarization causing abnormalities in QT interval. Objective: to evaluate the reproducibility and reliability of measurements of corrected QT interval (QTc) and its dispersion (QTcd) and correlate these parameters with LVH in hemodialysis patients. Methods: Case-control study involving hemodialysis patients and a control group. Clinical examination, blood sampling, transthoracic echocardiogram, and electrocardiogram were performed. Intra- and interobserver correlation and concordance tests were performed by Pearson´s correlation, Cohen's Kappa coefficient and Bland Altman diagram. Linear regression was used to analyze association of QTc or QTcd with HVE. Results: Forty-one HD patients and 37 controls concluded the study. Hemodialysis patients tended to have higher values of QTc, QTcd and left ventricular mass index (LVMi) than controls but statistical significance was not found. Correlation and concordance tests depicted better results for QTc than for QTcd. In HD patients, a poor but significant correlation was found between QTc and LVMi (R2 = 0.12; p = 0.03). No correlation was found between values of QTcd and LVMi (R2= 0.00; p=0.940). For the control group, the correspondent values were R2= 0.00; p = 0.67 and R2= 0.00; p = 0.94, respectively. Conclusion: We found that QTc interval, in contrast to QTcd, is a reproducible and reliable measure and had a weak but positive correlation with LVMi in HD patients.

Resumo Fundamentos: A hipertrofia ventricular esquerda (HVE) é muito comum em pacientes em hemodiálise e um fator de risco independente de mortalidade nessa população. O remodelamento do miocárdio, subjacente à HVE, pode afetar a repolarização ventricular, causando anormalidades no intervalo QT. Objetivo: avaliar a reprodutibilidade e confiabilidade das medidas do intervalo QT corrigido (QTc) e sua dispersão (QTcd), e correlacionar esses parâmetros com HVE em pacientes em hemodiálise. Métodos: Estudo caso-controle envolvendo pacientes em hemodiálise e um grupo controle. Foram realizados avaliação clínica, coleta de sangue, ecocardiografia transtorácica, e eletrocardiograma. Testes de correlação e concordância intraobservador e interobservador foram realizados por correlação de Pearson, coeficiente kappa de Cohen e diagrama de Bland Altman. A regressão linear foi usada para analisar a associação entre QTc ou QTcd e HE. Resultados: Quarenta e um pacientes em hemodiálise e 37 controles completaram o estudo. Houve uma tendência de os pacientes apresentarem valores mais altos de QTc, QTcd e de índice de massa ventricular esquerda que os controles, mas sem significância estatística. Os testes de correlação e de concordância apresentaram melhores resultados para QTc que para QTcd. Em pacientes em hemodiálise, uma correlação fraca, mas significativa foi encontrada entre QTc e IMVE (R2 = 0,12; p = 0,03). Não foi encontrada correlação entre QTcd e IMVE (R2 = 0,00; p=0,940). Para o grupo controle, esses valores correspondentes foram R2 = 0,00; p = 0,67 e R2 = 0,00; p = 0,94, respectivamente. Conclusão: o intervalo QTc, diferentemente do intervalo QTcd, é uma medida reprodutível e confiável, e apresentou uma correlação fraca, mas positiva com o IMVE em pacientes em hemodiálise.

Compromiso cardiovascular en pacientes pediátricos en diálisis peritoneal crónica / Cardiovascular disease in pediatric patients under chronic peritoneal dialysis

La diálisis peritoneal (DP) es la terapia de reemplazo renal más usada en niños portadores de enfermedad renal crónica terminal. La enfermedad cardiovascular es la principal causa de mortalidad en estos pacientes. OBJETIVO: Caracterizar pacientes pediátricos en DP crónica desde el punto de vista cardiovascular. PACIENTES Y MÉTODO: Estudio de corte transversal en pacientes en DP, estables según criterios DOQI. Se registraron variables epidemiológicas, dialíticas, bioquímicas y cardiovasculares. Se evaluó hipertrofia ventricular izquierda (HVI) por ecocardiografía. El índice de masa ventricular izquierda (IMVI) se calculó por índice talla/edad (g/m2.7). Se consideró HVI > 38,6 g/m2.7, y severa HVI > 51 g/m2.7. Se analizaron las variables continuas mediante ANOVA, y categóricas por χ2 o método exacto de Fisher. Se analizaron los datos en STATA 11.0. RESULTADOS: Se incluyeron 21 pacientes, 11 varones, edad 9,2 ± 3,5 años. El diagnóstico más frecuente fue displasia renal (52%). El KtV residual promedio fue de 0,8, y peritoneal 1,9. En la ecocardiografía, un 52% presentó HVI, un 91% de ellos en rango severo. Se demostró una relación significativa entre ultrafiltración y presión arterial sistólica, y entre IMVI y hemoglobina (p < 0,05). CONCLUSIONES: En este estudio reportamos una incidencia de HVI mayor al 50%, en su mayoría grado severo, lo cual evidencia el importante compromiso cardiovascular en estos pacientes. La hipertensión arterial y falla de ultrafiltración destacan como importantes factores relacionados a la hipertrofia ventricular izquierda.

Peritoneal dialysis (PD) is the most common renal replacement therapy used in pediatric patients with end stage renal disease. This population has a mortality rate 1,000 times greater compare to pediatric population, mainly due to cardiovascular causes. OBJECTIVE: To characterize pediatric patients on chronic PD in relation to dialysis and cardiovascular outcome. PATIENTS AND METHODS: Cross sectional study. Patients in stable PD according to DOQI criteria were selected. Epidemiological, dialytic, biochemical and cardiovascular variables were registered. Left Ventricular Mass Index (LVMI) was calculated by height/age (g/m2.7). Left Ventricular Hypertrophy (LVH) was diagnosed with > 38.6 g/m2.7, severe LVH > 51 g/m2.7. Data were analyzed using STATA 11.0. continuous variables using ANOVA test and categorical variables were analyzed using χ2 test or Fisher's exact test. RESULTS: 21 patients, 11 males. Mean age 9.2 ± 3.52 years. The most frequent diagnosis was renal dysplasia (52%). Residual and Peritoneal KtV were 0.8 and 1.9 respectively. Fifty-two percent of patients showed LVH, 91% in severe range. A significant relationship between ultrafiltration/m2 and systolic blood pressure was depicted. Also a significant relationship between left ventricular mass index and hemoglobin (p < 0.05) was founded. CONCLUSIONS: The majority of the population showed left ventricular hypertrophy -particularly severe LVH-, which confirms an increased CV risk in this population. Blood pressure and loss of ultrafiltration were founded to be correlated to LVH.

Electrocardiogram Performance in the Diagnosis of Left Ventricular Hypertrophy in Hypertensive Patients With Left Bundle Branch Block / Desempenho do Eletrocardiograma no Diagnóstico da Hipertrofia Ventricular Esquerda em Pacientes Hipertensos na Presença de Bloqueio de Ramo Esquerdo

Abstract Background: Left ventricular hypertrophy (LVH) is an important risk factor for cardiovascular events, and its detection usually begins with an electrocardiogram (ECG). Objective: To evaluate the impact of complete left bundle branch block (CLBBB) in hypertensive patients in the diagnostic performance of LVH by ECG. Methods: A total of 2,240 hypertensive patients were studied. All of them were submitted to an ECG and an echocardiogram (ECHO). We evaluated the most frequently used electrocardiographic criteria for LVH diagnosis: Cornell voltage, Cornell voltage product, Sokolow-Lyon voltage, Sokolow-Lyon product, RaVL, RaVL+SV3, RV6/RV5 ratio, strain pattern, left atrial enlargement, and QT interval. LVH identification pattern was the left ventricular mass index (LVMI) obtained by ECHO in all participants. Results: Mean age was 11.3 years ± 58.7 years, 684 (30.5%) were male and 1,556 (69.5%) were female. In patients without CLBBB, ECG sensitivity to the presence of LVH varied between 7.6 and 40.9%, and specificity varied between 70.2% and 99.2%. In participants with CLBBB, sensitivity to LVH varied between 11.9 and 95.2%, and specificity between 6.6 and 96.6%. Among the criteria with the best performance for LVH with CLBBB, Sokolow-Lyon, for a voltage of ≥ 3,0mV, stood out with a sensitivity of 22.2% (CI 95% 15.8 - 30.8) and specificity of 88.3% (CI 95% 77.8 - 94.2). Conclusion: In hypertensive patients with CLBBB, the most often used criteria for the detection of LVH with ECG showed significant decrease in performance with regards to sensitivity and specificity. In this scenario, Sokolow-Lyon criteria with voltage ≥3,0mV presented the best performance.

Resumo Fundamento: A hipertrofia ventricular esquerda (HVE) é importante fator de risco para eventos cardiovasculares, e sua identificação se inicia, geralmente, pela realização do eletrocardiograma (ECG). Objetivo: Avaliar, em hipertensos, o impacto do bloqueio completo do ramo esquerdo (BCRE) no desempenho diagnóstico da HVE pelo ECG. Métodos: Foram estudados 2.240 pacientes hipertensos. Todos realizaram ECG e ecocardiograma (ECO). Foram avaliados os critérios eletrocardiográficos mais utilizados para o diagnóstico de HVE: Cornell voltagem, Cornell voltagem produto, Sokolow-Lyon voltagem, Sokolow-Lyon produto, RaVL, RaVL produto, RaVL+SV3, Relação RV6/RV5, padrão strain, aumento atrial esquerdo e o intervalo QT. O padrão de identificação da HVE foi o índice de massa do ventrículo esquerdo (IMVE) obtido pelo ECO em todos participantes. Resultados: A média de idade foi de 11,3 anos ± 58,7 anos, 684 (30,5%) homens e 1.556 (69,5%) mulheres. Nos participantes sem BCRE, a sensibilidade do ECG para a presença de HVE variou de 7,6 a 40,9%, e a especificidade de 70,2 a 99,2%. Nos participantes com BCRE, a sensibilidade para a HVE variou de 11,9 a 95,2%, e a especificidade de 6,6 a 96,6%. Dentre os critérios com melhor desempenho para HVE com BCRE, destacou-se o de Sokolow-Lyon para voltagem ≥ 3,0mV com sensibilidade de 22,2% (IC 95% 15,8 - 30,8) e especificidade de 88,3% (IC 95% 77,8 - 94,2). Conclusão: Nos hipertensos com BCRE, os critérios mais utilizados para detecção da HVE pelo ECG apresentaram diminuição significativa de desempenho da sensibilidade e especificidade. Nesse cenário, o critério de Sokolow-Lyon com voltagem ≥3,0mV apresentou melhor comportamento.

Influência dos critérios de indexação da massa do ventrículo esquerdo no diagnóstico de hipertrofia ao ecocardiograma em crianças com insuficiência renal crônica / Influence of left ventricular mass indexation criteria in the diagnosis of left ventricular hypertrophy by echocardiogram: study in children with chronic renal disease

Fundamento: O diagnóstico ecocardiográfico de hipertrofia ventricular esquerda (HVE) em crianças baseia-se no cálculo damassa do ventrículo esquerdo (VE) indexada. Entretanto, o critério de indexação ainda não é consenso.Objetivo: Comparar diferentes critérios usados no diagnóstico de HVE à ecocardiografia em crianças.Método: Foram incluídas crianças com doença renal crônica (DRC) em diálise (grupo DI) ou em tratamento conservador (grupoTC). Foram obtidas as medidas e calculada a massa do VE conforme recomendado. Os critérios de HVE utilizados foram: 1)massa (g) – HVE conforme gênero e área da superfície corporal (ASC); 2) massa (g) indexada à ASC (g/m2) – HVE conforme gênero e ASC; 3) massa em gramas indexada à altura (m) à potência de 2,7 (g/m2,7) – diagnóstico de HVE conforme nomograma de idade, gênero e altura; 4) escore z http://parameterz.blogspot.com/2008/09/lv-mass-z-scores – HVE se > 2 desvios-padrão).As proporções de HVE foram comparadas por teste do X2; significante se p < 0,05.Resultados: Sessenta crianças com DRC foram incluídas; 34 no grupo DI (17 meninos; mediana da idade = 109 meses) e 26no grupo TC (15 meninos; mediana da idade = 80 meses). Conforme o critério, no grupo total, as proporções de HVE foram, respectivamente, 31/60, 33/60, 41/60 e 31/60 (p = 0,049), menor pelo critério 2 em relação ao 3 (p = 0,026); no grupo DI foram23/34; 23/34; 31/34 e 29/34 (p = 0,006), maior com o critério 3 em relação aos critérios 1 (p = 0,033) e 2 (p = 0,004) e com ocritério 4 em relação ao 2 (p = 0,029); no grupo TC foram 8/26; 10/26; 10/26 e 2/26 (p = 0,038), menor pelo critério 4 em relaçãoaos critérios 2 (p = 0,038) e 3 (p = 0,009).

Background: the echocardiographic diagnosis of left ventricular hypertrophy (LVH) in children is based on the indexed left ventricle mass calculation.However, the indexation criterion is still not defined.Objective: to compare different criteria used for the diagnosis of LVH by echocardiography in children.Method: The study included children with chronic renal disease (CRD) in dialysis (DI) or in conservative treatment (CT). Measures for left ventriclemass calculation were obtained as recommended. The criteria used for LVH were: 1) mass (g) – LVH according to gender and body surface area(BSA, m2) – based on large study of normal Brazilian children; 2) mass indexed to body surface area (g/m2) – LVH according to gender and bodysurface area (BSA, m2) – based on large study of normal Brazilian children; 3) g/altura2,7 but diagnosis of LVH by a nomogram of age, gender andheight; 4) z score (http://parameterz.blogspot.com/2008/09/lv-mass-z-scores) – LVH if > 2 standard-deviation. The proportion of LVH among thegroups were compared by X2; significant if p < 0.05.Results: 60 children with CKD were included; 34 in DI (17 boys; median of age= 109 months) and 26 in CT (15 boys; median of age= 80 months).According to each criteria, in the hole group, the proportions of LVH were, respectively, 31/60, 33/60, 41/60 e 31/60 (p=0.049), lower for criterion2 compared to 3 (p=0.026); in DI group were 23/34; 23/34; 31/34 e 29/34 (p=0.006), higher with criterion 3 compared to criteria 1 (p=0.033)and 2 (p=0.004), and with 4 compared to 2 (p=0.029); in TC group were 8/26; 10/26; 10/26 e 2/26 (p=0.038), lower for criterion 4 comparedto criteria 2 (p=0.038) and 3 (p=0.009). Conclusion: in children with CKD the proportion of LVH by echocardiography was different according to the criterion used. (Arq Bras Cardiol:Imagem cardiovasc. 2016;29(2):42-46).

Impacto do padrão geométrico ventricular na remodelação cardíaca após o infarto do miocárdio / Impact of ventricular geometric pattern on cardiac remodeling after myocardial infarction

FUNDAMENTO: A relevância do padrão de geometria após o infarto do miocárdio não é conhecida. OBJETIVOS: Analisar a presença de diferentes padrões de geometria ventricular esquerda (VE) e seu impacto como preditor de remodelação em pacientes com infarto do miocárdio. MÉTODOS: Pacientes com infarto agudo anterior (n = 80) foram divididos de acordo com o padrão de geometria: normal (índice de massa [IMVE] normal e espessura relativa da parede [ERP] normal), remodelação concêntrica (IMVE normal e ERP aumentada), hipertrofia concêntrica (IMVE e ERP aumentadas) e hipertrofia excêntrica (IMVE aumentado e ERP normal). Após seis meses, foi repetido o ecocardiograma. RESULTADOS: Quatro pacientes foram a óbito. Dos sobreviventes, 41 apresentaram remodelação (R+), enquanto 39 não remodelaram (R-). Considerando-se o padrão geométrico, houve a seguinte distribuição: 24 pacientes com padrão normal, 13 com remodelação concêntrica, 29 com hipertrofia concêntrica e 14 com hipertrofia excêntrica. Os pacientes que remodelaram apresentaram maiores tamanhos de infarto analisados pelo pico da CPK (R+ = 4.610 (1.688 - 7.970), R- = 1.442 (775 - 4.247), p < 0,001) e da CK-MB (R+ = 441 (246 - 666), R- = 183 (101 - 465), p < 0,001), tendência a maior prevalência de remodelação concêntrica (R+ = 10, R- = 3, p = 0,08) e menor prevalência de hipertrofia excêntrica (R+ = 2, R- = 12, p = 0,006). Na análise de regressão multivariada, o tamanho do infarto foi preditor (OR = 1,01; p = 0,020) e a hipertrofia excêntrica foi fator protetor (OR = 0,189; p = 0,046) de remodelação ventricular após a oclusão coronariana. CONCLUSÃO: O padrão de geometria ventricular pode ter impacto no processo de remodelação em pacientes com infarto do miocárdio.

BACKGROUND: The relevance of left ventricular (LV) geometric pattern after myocardial infarction is not known. OBJECTIVES: To analyze the presence of different LV geometric patterns and teir impact as a predictor of remodeling in patients with myocardial infarction. METHODS: Patients with anterior acute myocardial infarction (n = 80) were divided according to the geometric pattern: normal (normal left ventricular mass index [LVMI] and normal relative wall thickness [RWT]), concentric remodeling (normal LVMI and increased RWT), concentric hypertrophy (increased LVMI and RWT) and eccentric hypertrophy (increased LVMI and normal RWT). After six months, echocardiographic assessment was repeated. RESULTS: Four patients died. Of the survivors, 41 showed remodeling (R +), whereas 39 did not (R-). Considering the geometric pattern, the cases were distributed as follows: 24 patients with normal pattern, 13 with concentric remodeling, 29 with concentric hypertrophy and 14 with eccentric hypertrophy. Patients who showed remodeling had larger infarction sizes analyzed by peak CPK (R + = 4,610 (1,688-7,970), R- = 1,442 (775-4247), p <0.001) and CK-MB (R + = 441 (246 - 666), R- = 183 (101-465), p <0.001), trend towards higher prevalence of concentric remodeling (R+ = 10, R- = 3, p = 0.08) and lower prevalence of eccentric hypertrophy (R + = 2 R- = 12, p = 0.006). In the multivariate regression analysis, infarction size was a predictor (OR = 1.01, p = 0.020) and eccentric hypertrophy was a protective factor (OR = 0.189, p = 0.046) of ventricular remodeling after coronary occlusion. CONCLUSION: The LV geometric pattern of can have an impact on the remodeling process in patients with myocardial infarction.

Estudo da sístole elétrica ventricular nos insuficientes renais crônicos hemodialisados / Study of ventricular electrical systole in patients with end-stage kidney disease on hemodialysis

FUNDAMENTO: Os indivíduos com insuficiência renal crônica terminal estão sujeitos a um elevado estresse cardíaco pelo carácter repetitivo e intermitente da terapia dialítica. As alterações na sístole elétrica ventricular induzidas pela necessária terapia dialítica são um contributo importante na predição da ocorrência de morte súbita arrítmica na insuficiência renal crônica terminal. OBJETIVO: O objetivo principal desta investigação é avaliar o comportamento da repolarização ventricular em face da terapia dialítica, mediante o estudo do intervalo QTc e dispersão do QTc. MÉTODOS: A amostra em estudo inclui 47 indivíduos sujeitos a hemodiálise (61,7% do sexo masculino e 38,3% do sexo feminino) com idade média de 66,79 ± 13,16 anos. Todos os indivíduos foram sujeitos a três eletrocardiogramas realizados em três momentos durante a terapia dialítica (pré, durante e após a sessão), sendo posteriormente analisada a sístole elétrica ventricular. RESULTADOS: Ocorreu um aumento do intervalo QTc máximo e da dispersão do QTc associado à terapia dialítica. Aliado ao aumento desses intervalos ocorreu um aumento do número de indivíduos com critérios eletrocardiográficos para hipertrofia ventricular esquerda, registando-se no período pós-diálise uma média superior do intervalo QTc máximo (473 ± 27,63 mseg) e da dispersão do QTc (58,95 ± 18,87 mseg) desses indivíduos, comparativamente aos indivíduos sem HVE, 455,21 ± 26,85 mseg e 44 ± 16,41 mseg, respectivamente. CONCLUSÃO: O presente estudo confirmou um aumento do intervalo QTc e da dispersão do QTc associado à terapia dialítica. Esse aspecto reforça a dependência da repolarização ventricular em relação ao equilíbrio hídrico e eletrolítico e sugere um perfil de maior vulnerabilidade arrítmica associada à terapia dialítica.

BACKGROUND: Patients with end-stage kidney disease (ESKD) experience elevated cardiac stress because of the repetitive and intermittent character of dialysis. Changes in ventricular electrical systole induced by necessary dialysis significantly contribute to predict sudden death due to arrhythmia in ESKD. OBJECTIVE: The major objective of this study was to assess the behavior of ventricular repolarization in dialysis by analyzing QTc interval and QTc dispersion. METHODS: This study sample consisted of 47 patients undergoing hemodialysis (61.7% males and 38.3% females), whose mean age was 66.79±13.16 years. All of them underwent three electrocardiograms performed before, during and after one dialysis session. Ventricular electrical systole was analyzed later. RESULTS: An increase in maximum QTc interval and QTc dispersion associated with dialysis was observed. In addition, an increase in the number of individuals meeting the electrocardiographic criteria for left ventricular hypertrophy (LVH) was observed. After dialysis, higher means of the maximum QTc interval (473 ± 27.63 mseg) and of the QTc dispersion (58.95 ± 18.87 mseg) were observed in individuals with LVH as compared with those in individuals without LVH (455.21 ± 26.85 mseg and 44 ± 16.41 mseg, respectively). CONCLUSION: This study confirmed an increase in the QTc interval and QTc dispersion associated with dialysis. That emphasizes the dependence of ventricular repolarization on fluid and electrolyte balance, and suggests a profile of higher vulnerability to arrhythmia associated with dialysis .

Evaluacion de la funcion diastolica durante y post-ejercicio isometrico en pacientes con hipertension arterial / Evaluation of diastolic function during and post-exercise in patients with arterial hypertension

Es conocido que los pacientes con hipertrofia ventricular por hipertensión arterial presentan alteraciones diastólicas, particularmente durante el ejercicio. Sin embargo, es controvertido si luego del esfuerzo esta disfuncion se normaliza. El objetivo fue evaluar la función diastólica durante y después de la realización de ejercicio, en pacientes con hipertensión arterial. Se estudiaron 6 pacientes controles (grupo 1, G1) y 7 con diagnóstico de hipertensión arterial (Grupo 2, G2). Los pacientes fueron sometidos a un cateterismo cardíaco y realizaron ejercicio isométrico durante el estudio, hasta que la frecuencia cardíaca se incrementó un 43+ o -7% (p<0.05), con respecto al valor basal. Se midió la presión sistólica ventricular izquierda (PSVI) y la presión de fin de diástole (PFDVI) y se calculó la máxima velocidad de ascenso de la presión (+dP/dtmáx), la constante de tiempo de caída de la presión ventricular tau, el tiempo que tarda en caer la presión hasta un 50% de su valor al momento de la -dP/dtmáx (t1/2, mseg). La PSVI se incrementó, durante el ejercicio, desde 140+ o -3 hasta 195+ o -14 mm Hg (p<0.05) en G1 y de 161¡À9 hasta 238 + o -15 mm Hg en G2; retornando luego a susvalores basales. El tau y el t1/2 se incrementaron en G2, durante el ejercicio, desde un valor de 23+ o -2 y 15 + o -2 mseg hasta 35 + o - 7 y 23¡ + o - 4 mseg, respectivamente. Luego del esfuerzo, ambas variables permanecieron elevadas con respecto al basal, alcanzando valores de 41 + o - 6 mseg (p<0.05) y 23 + o -3 mseg (p<0.05), respectivamente. El ejercicio isométrico disminuye la velocidad de relajación e incrementa la PFDVI en pacientes con hypertension arterial e hipertrofia del ventrículo izquierdo. Luego del ejercicio la relajación permaneció alterada, a pesar de que el resto de las variables hemodinámicas retornaron a su valor basal, sugiriendo la presencia de atontamiento miocárdico

It is known that patients with arterial hypertension and ventricular hypertrophy have diastolicalterations, in particular during exercise. However, it is controversial if diastolic dysfunction continues once exercisehad concluded. The objective was to assess the effects of isometric exercise on the diastolic function in patientswith arterial hypertension. Five control patients (group 1, G1) and 7 patients with arterial hyper-tension (group 2,G2) were studied. All patients underwent cardiac catheterization and performed isometric exercise until heartrate increased 43+or -7%. Left ventricular systolic pressure (LVSP) and end diastolic pressure (LVEDP) weremeasured. We calculated, +dP/dtmax, the time constant of isovolumic pressure decay (tau) and t1/2 were allmeasured. Results: The LVSP increased in G1 and G2 during exercise from 140+ or -3 to 195+ or -14 mm Hg (p<0.05)and 161+ or -9 to 238+ or -15 mm Hg, respectively; returning to their basal values once exercise had concluded. The tau and t1/2 increased, while exercising in G2, from 23+ or -2 and 15+ or - msec to 35+ or -7 and 23+ or -4 msec, respectively. After exercise both variables continued elevated reaching 41+ or -6 msec (p<0.05) and 23+ or -3 msec (p<0.05), respectively. In conclusion, isometric exercise decreases relaxation rate and increases LVEDP in patients with arterial hypertension and ventricular hypertrophy. After exercise, isovolumic relaxation remained altered suggesting the presence of stunned myocardium

Early abnormalities of left ventricular function in essential hypertension induced by exercise

In order to assess their ventricular function at rest and during exercise, 42 essential hypertensives (164 +/- 2/98.7 +/- 2 mmHg) and 12 normotensives (131.7 +/- 4/81.2 +/- 1 mmHg) were studied. Ejection fraction (EF), peak filling rate (PFR) and peak ejection rate (PER) were measured by means of gated radionuclide ventriculography. At rest, no differences in EF, PFR and PER between hypertensives and normotensives were found. During exercise, hypertensives showed lower PFR (5.3 +/- 0.2 EDV/s) and EF (67.7 +/- 1%) than normotensives (PFR 7 +/- 0.5 EDV/s, p < 0.005 and EF 79.4 +/- 2%, p < 0.001). Likewise, hypertensive showed a lower increase from rest to exercise in PFR and in EF than normotensives p < 0.001. In addition, hypertensives showed a great individual variability in EF response to exercise, where 23 patients increased EF more than 5% and 19 patients failed to increase it during stress. Moreover, the last group of patients had higher systolic blood pressure (SBP) both at rest and during exercise than patients who increased EF, p < 0.01. In addition, there was a significantly negative correlation between resting SBP and the variation of Ef (r = 0.47 y: 163.1-0.79X, p < 0.01). Left ventricular mass (LVM) was similar in the two groups of hypertensives. On the other hand, there were no differences in any of the variables analyzed between the hypertensives with LV hypertrophy and those with normal LVM. These findings suggest that abnormalities in both systolic and diastolic LV during exercise may be found in hypertensive patients even before myocardial hypertrophy can be detected