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1.
Braz. j. med. biol. res ; 46(11): 974-984, 18/1jan. 2013. tab, graf
Artigo em Inglês | LILACS | ID: lil-694028

RESUMO

The SEARCH-RIO study prospectively investigated electrocardiogram (ECG)-derived variables in chronic Chagas disease (CCD) as predictors of cardiac death and new onset ventricular tachycardia (VT). Cardiac arrhythmia is a major cause of death in CCD, and electrical markers may play a significant role in risk stratification. One hundred clinically stable outpatients with CCD were enrolled in this study. They initially underwent a 12-lead resting ECG, signal-averaged ECG, and 24-h ambulatory ECG. Abnormal Q-waves, filtered QRS duration, intraventricular electrical transients (IVET), 24-h standard deviation of normal RR intervals (SDNN), and VT were assessed. Echocardiograms assessed left ventricular ejection fraction. Predictors of cardiac death and new onset VT were identified in a Cox proportional hazard model. During a mean follow-up of 95.3 months, 36 patients had adverse events: 22 new onset VT (mean±SD, 18.4±4‰/year) and 20 deaths (26.4±1.8‰/year). In multivariate analysis, only Q-wave (hazard ratio, HR=6.7; P<0.001), VT (HR=5.3; P<0.001), SDNN<100 ms (HR=4.0; P=0.006), and IVET+ (HR=3.0; P=0.04) were independent predictors of the composite endpoint of cardiac death and new onset VT. A prognostic score was developed by weighting points proportional to beta coefficients and summing-up: Q-wave=2; VT=2; SDNN<100 ms=1; IVET+=1. Receiver operating characteristic curve analysis optimized the cutoff value at >1. In 10,000 bootstraps, the C-statistic of this novel score was non-inferior to a previously validated (Rassi) score (0.89±0.03 and 0.80±0.05, respectively; test for non-inferiority: P<0.001). In CCD, surface ECG-derived variables are predictors of cardiac death and new onset VT.

2.
Braz. j. med. biol. res ; 44(12): 1285-1290, Dec. 2011. ilus, tab
Artigo em Inglês | LILACS | ID: lil-606540

RESUMO

Some thrombophilias and severe preeclampsia may increase the risk for preterm deliveries and fetal death due to placental insufficiency. Our objective was to evaluate clinical and laboratory data as predictors of preeclampsia in a population of mothers with 3rd trimester fetal losses or preterm deliveries. In a longitudinal retrospective study, 54 consecutive women (age range: 16 to 39 years) with normotensive pregnancies were compared to 79 consecutive women with preeclampsia (age range: 16 to 43 years). Weight accrual rate (WAR) was arbitrarily defined as weight gain from age 18 years to the beginning of pregnancy divided by elapsed years. Independent predictors of preeclampsia were past history of oligomenorrhea, WAR >0.8 kg/years, pre-pregnancy or 1st trimester triglyceridemia >150 mg/dL, and elevated acanthosis nigricans in the neck. In a multivariate logistic regression model, two or more predictors conferred an odds ratio of 15 (95 percentCI [5.9-37]; P < 0.001) to develop preeclampsia (85 percent specificity, 73 percent sensitivity, c-statistic of 81 ± 4 percent; P < 0.0001). Clinical markers related to insulin resistance and sedentary lifestyles are strong independent predictors of preeclampsia in mothers with 3rd trimester fetal losses or preterm deliveries due to placental insufficiency. Women at risk for preeclampsia in this particular population might benefit from measures focused on overcoming insulin resistance.


Assuntos
Adolescente , Adulto , Feminino , Humanos , Recém-Nascido , Gravidez , Adulto Jovem , Resistência à Insulina/fisiologia , Pré-Eclâmpsia/etiologia , Comportamento Sedentário , Acantose Nigricans/complicações , Biomarcadores/sangue , Métodos Epidemiológicos , Oligomenorreia/complicações , Resultado da Gravidez , Pré-Eclâmpsia/sangue , Pré-Eclâmpsia/fisiopatologia
3.
Braz. j. med. biol. res ; 42(8): 722-730, Aug. 2009. graf, tab
Artigo em Inglês | LILACS | ID: lil-520779

RESUMO

The 24-h heart rate variability and QT-interval adaptation was investigated in perinatally HIV-infected preschool children classified according to immunological status in order to assess autonomic function at early stages of infection. Thirty-five perinatally HIV-infected and clinically stable children (4.8 ± 0.3 years) were enrolled after approval of the study by the University Hospital Pedro Ernesto Ethics Committee and written informed parental consent was obtained. The children were classified according to peripheral CD4+ count (cells/µL) as follows: group 1, N = 11 (≥1000); group 2, N = 7 (≥500 and <1000); group 3, N = 17 (<500). Left ventricular ejection fraction (>55%), 24-h RR interval variability (RRV) indexes (NN, SDANN, SDNN index, r-MSSD) and 24-h QT and Bazett-corrected QT (QTc) were determined, and groups were matched for age, body surface area, and left ventricular ejection fraction, reducing biases in RRV. The peak differences (∆) between the highest and lowest RRV and QT indexes were extracted from nocturnal (1 am-6 am) and daytime (1 pm-6 pm) hourly assessed segments, respectively. Pearson’s correlation (r) and Kruskal-Wallis ANOVA were used to compare groups. CD4+ count correlated positively with ∆NN (r = 0.45; P = 0.003). There were no significant differences in daytime NN among groups. Nighttime SDNN index (P = 0.01), nighttime r-MSSD (P = 0.003), ∆NN (P = 0.01), ∆SDNN index (P = 0.03) and ∆r-MSSD (P = 0.004) were significantly lower in group 3 than in the other groups. Expected nighttime QTc-interval lengthening was not observed in all groups. In perinatally HIV-infected preschool children with preserved left ventricular systolic function, parasympathetic-mediated autonomic dysfunction parallels immune status, impairing both RRV and circadian QTc interval adaptation.


Assuntos
Pré-Escolar , Feminino , Humanos , Masculino , Sistema Nervoso Autônomo/fisiopatologia , Ritmo Circadiano/fisiologia , Infecções por HIV/fisiopatologia , Sistema de Condução Cardíaco/fisiopatologia , Frequência Cardíaca/fisiologia , Sistema Nervoso Autônomo/imunologia , Estudos Transversais , Ritmo Circadiano/imunologia , Eletrocardiografia Ambulatorial , Infecções por HIV/imunologia , Sistema de Condução Cardíaco/imunologia , Frequência Cardíaca/imunologia , Carga Viral
4.
Braz. j. med. biol. res ; 42(3): 251-262, Mar. 2009. ilus, tab, graf
Artigo em Inglês | LILACS | ID: lil-507349

RESUMO

Atrial fibrillation (AF) affects subjects with Chagas' disease and is an indicator of poor prognosis. We investigated clinical, echocardiographic and electrocardiographic variables of Chagas' disease in a long-term longitudinal study as predictors of a new-onset AF episode lasting >24 h, nonfatal embolic stroke and cardiac death. Fifty adult outpatients (34 to 74 years old, 62 percent females) staged according to the Los Andes classification were enrolled. During a follow-up of (mean ± SD) 84.2 ± 39.0 months, 9 subjects developed AF (incidence: 3.3 ± 1.0 percent/year), 5 had nonfatal stroke (incidence: 1.3 ± 1.0 percent/year), and nine died (mortality rate: 2.3 ± 0.8 percent/year). The progression rate of left ventricular mass and left ventricular ejection fraction was significantly greater in subjects who experienced AF (16.4 ± 20.0 g/year and -8.6 ± 7.6 percent/year, respectively) than in those who did not (8.2 ± 8.4 g/year; P = 0.03, and -3.0 ± 2.5 percent/year; P = 0.04, respectively). In univariate analysis, left atrial diameter ≥3.2 cm (P = 0.002), pulmonary arterial hypertension (P = 0.035), frequent premature supraventricular and ventricular contraction counts/24 h (P = 0.005 and P = 0.007, respectively), ventricular couplets/24 h (P = 0.002), and ventricular tachycardia (P = 0.004) were long-term predictors of AF. P-wave signal-averaged ECG revealed a limited long-term predictive value for AF. In chronic Chagas' disease, large left atrial diameter, pulmonary arterial hypertension, frequent supraventricular and ventricular premature beats, and ventricular tachycardia are long-term predictors of AF. The rate of left ventricular mass enlargement and systolic function deterioration impact AF incidence in this population.


Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fibrilação Atrial/fisiopatologia , Cardiomiopatia Chagásica/fisiopatologia , Fibrilação Atrial/etiologia , Doença Crônica , Cardiomiopatia Chagásica/complicações , Ecocardiografia , Eletrocardiografia , Seguimentos , Valor Preditivo dos Testes , Prognóstico , Remodelação Ventricular/fisiologia
5.
Braz. j. med. biol. res ; 40(2): 199-208, Feb. 2007. tab, graf
Artigo em Inglês | LILACS | ID: lil-440495

RESUMO

Increased heart rate variability (HRV) and high-frequency content of the terminal region of the ventricular activation of signal-averaged ECG (SAECG) have been reported in athletes. The present study investigates HRV and SAECG parameters as predictors of maximal aerobic power (VO2max) in athletes. HRV, SAECG and VO2max were determined in 18 high-performance long-distance (25 ± 6 years; 17 males) runners 24 h after a training session. Clinical visits, ECG and VO2max determination were scheduled for all athletes during thew training period. A group of 18 untrained healthy volunteers matched for age, gender, and body surface area was included as controls. SAECG was acquired in the resting supine position for 15 min and processed to extract average RR interval (Mean-RR) and root mean squared standard deviation (RMSSD) of the difference of two consecutive normal RR intervals. SAECG variables analyzed in the vector magnitude with 40-250 Hz band-pass bi-directional filtering were: total and 40-æV terminal (LAS40) duration of ventricular activation, RMS voltage of total (RMST) and of the 40-ms terminal region of ventricular activation. Linear and multivariate stepwise logistic regressions oriented by inter-group comparisons were adjusted in significant variables in order to predict VO2max, with a P < 0.05 considered to be significant. VO2max correlated significantly (P < 0.05) with RMST (r = 0.77), Mean-RR (r = 0.62), RMSSD (r = 0.47), and LAS40 (r = -0.39). RMST was the independent predictor of VO2max. In athletes, HRV and high-frequency components of the SAECG correlate with VO2max and the high-frequency content of SAECG is an independent predictor of VO2max.


Assuntos
Humanos , Masculino , Feminino , Adulto , Frequência Cardíaca/fisiologia , Consumo de Oxigênio/fisiologia , Resistência Física/fisiologia , Corrida/fisiologia , Estudos de Casos e Controles , Eletrocardiografia/métodos , Modelos Teóricos , Valor Preditivo dos Testes , Processamento de Sinais Assistido por Computador
6.
Braz. j. med. biol. res ; 40(2): 167-178, Feb. 2007. graf, tab
Artigo em Inglês | LILACS | ID: lil-440499

RESUMO

The objective of the present study was to investigate clinical, echocardiographic and electrocardiographic (12-lead resting ECG, 24-h ambulatory ECG monitoring and signal-averaged ECG (SAECG)) parameters in subjects with chronic Chagas' disease in a long-term follow-up as prognostic markers for adverse outcomes. Fifty adult outpatients (34 to 74 years old, 31 females) staged according to Los Andes class I, II or III and complaining of palpitation were enrolled in a longitudinal study. SAECG was analyzed in time and frequency domains and the endpoint was a composite of cardiac death and ventricular tachycardia. During a follow-up of 84.2 ± 39.0 months, 34.0 percent of the patients developed adverse outcomes (9 cardiac deaths and 11 episodes of ventricular tachycardia). After optimal dichotomization, in a stepwise multivariate Cox-hazard regression model, apical aneurysm (HR = 3.7; 95 percent CI = 1.2-1.3; P = 0.02), left ventricular ejection fraction <62 percent (HR = 4.60; 95 percent CI = 1.39-15.24; P = 0.01) and incidence of ventricular premature contractions >614 per 24 h (hazard ratio = 6.1; 95 percent CI = 1.7-22.6; P = 0.006) were independent predictors of the composite endpoint. Although a high frequency content in SAECG demonstrated association with the presence of left ventricular dysfunction and myocardial fibrosis, its predictive value for the composite endpoint was not significant. Apical aneurysms, reduced left ventricular function and a high incidence of ventricular ectopic beats over a 24-h period have a strong predictive value for a composite endpoint of cardiac death and ventricular tachycardia in subjects with chronic Chagas' disease.


Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Cardiomiopatia Chagásica/complicações , Morte Súbita Cardíaca/etiologia , Taquicardia Ventricular/etiologia , Doença Crônica , Estudos de Coortes , Cardiomiopatia Chagásica/mortalidade , Ecocardiografia , Eletrocardiografia , Seguimentos , Valor Preditivo dos Testes , Prognóstico
7.
Arq. bras. cardiol ; 81(5): 483-493, nov. 2003. tab
Artigo em Inglês, Português | LILACS | ID: lil-351132

RESUMO

OBJECTIVE: Noninvasive cardiac assessment of newborns and infants of women with systemic lupus erythematosus. The children had no congenital total atrioventricular block and were compared with the children of healthy women. METHODS: We prospectively assessed 13 newborns and infants aged 1 to 60 days, children of women with systemic lupus erythematosus and without congenital total atrioventricular block. These children were compared with 30 children of women who had no lupus or anti-Ro/SSA antibodies, and no risk factors for congenital heart disease either. Their age groups matched. The following examinations were performed: cardiological physical examination, electrocardiography, echocardiography, and signal-averaged electrocardiography. RESULTS: The statistical analysis showed no significant difference in ventricular function or in the cardiac conduction system between the groups. CONCLUSION: In regard to the conduction system and ventricular function in the absence of total atrioventricular block, no statistically significant difference was observed between the children of women with systemic lupus erythematosus and children of healthy women


Assuntos
Humanos , Masculino , Feminino , Recém-Nascido , Lactente , Eletrocardiografia , Bloqueio Cardíaco/diagnóstico , Lúpus Eritematoso Sistêmico/diagnóstico , Anticorpos Antinucleares/sangue , Ecocardiografia Doppler em Cores , Frequência Cardíaca , Bloqueio Cardíaco/imunologia , Bloqueio Cardíaco , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico , Estudos Prospectivos , Estatísticas não Paramétricas
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