Ivana Antelmi

Recuperação da freqüência cardíaca após teste de esforço em esteira ergométrica e variabilidade da freqüência cardíaca em 24 horas em indivíduos sadios

FUNDAMENTO: A recuperacao da frequencia cardiaca apos o eletrocardiograma de esforco em esteira ergometrica e modulada pelo sistema nervoso autonomo. A analise da variabilidade da frequencia cardiaca (VFC) pode fornecer informacoes valiosas sobre o controle do sistema nervoso autonomo sobre o sistema cardiovascular. OBJETIVO: O objetivo deste estudo foi testar a hipotese de associacao entre a recuperacao da frequencia cardiaca apos teste de esforco em esteira ergometrica e a variabilidade da frequencia cardiaca. METODOS: Foram estudamos 485 individuos sem evidencia de cardiopatia com media de idade de 42± 12,1 (faixa etaria de 15 a 82) anos, 281 (57.9%) dos quais do sexo feminino, submetidos a um teste de esforco em esteira ergometrica e avaliacao da VFC nos dominios do tempo (SDNN, SDANN, SDNNi, rMSSD e pNN50) e da frequencia (LF, HF, VLF e razao LF/HF) durante monitoramento eletrocardiografico ambulatorial de 24 horas. RESULTADOS: A recuperacao da frequencia cardiaca foi de 30 ± 12 batimentos no 1o minuto e 52± 13 batimentos no 2o minuto apos o exercicio. Os individuos mais jovens de recuperaram mais rapido do 2o ao 5o minuto apos o exercicio (r = 0,19-0,35, P < 0,05). As mulheres se recuperaram mais rapido que os homens (4 ± 1,1 batimentos a menos no 1o minuto, p < 0,001; 5,7 ± 1,2 batimentos a menos no 2o minuto, p < 0,01; e 4,1± 1,1 batimentos a menos no 3o minuto, p < 0.001). Nao houve correlacao significante entre a recuperacao da frequencia cardiaca e a VFC no 1o e 2o minutos apos o exercicio. Os indices SDNN, SDANN, SDNNi, rMSSD e pNN50 so apresentaram uma correlacao significante com a recuperacao da frequencia cardiaca no 3o e 4o minutos. CONCLUSAO: A hipotese de associacao entre recuperacao da frequencia cardiaca e VFC em 24 horas nos primeiros dois minutos apos o exercicio nao foi comprovada neste estudo. A recuperacao da frequencia cardiaca foi associada com idade e sexo.

Cardiac Arrhythmias and Atrioventricular Block in a Cohort of Asymptomatic Individuals without Heart Disease

Aims: To evaluate cardiac arrhythmias and rhythm disturbances on 24 h ambulatory electrocardiographic monitoring in a cohort of asymptomatic healthy individuals with normal clinical examination. Methods and Results: 625 asymptomatic healthy individuals, in the age range 15–83 (mean 42, SD 11.9) years; 276 (44.2%) men and 349 (55.8%) women were submitted to 24-hour ambulatory electrocardiographic monitoring. Statistical analysis was performed with likelihood ratio test and automatic backward logistic regression. The frequency of atrial arrhythmias (p < 0.0001; OR 1.059; 95% CI 1.050–1068) and of ventricular arrhythmias (p < 0.0001; OR 1.023; 95% CI 1.017–1.029) increased for each age increase of 1 year; neither atrial nor ventricular arrhythmias demonstrated a statistically significant difference relative to gender. Transient second-degree atrioventricular block (Mobitz I) was observed in 14 (2.2%) individuals and was more frequent in individuals with resting heart rate <60 bpm (p = 0.006; OR 6.7, 95% CI 1.7–25.5). Conclusion: The frequency of atrial and ventricular arrhythmias increased with age and did not demonstrate a significant difference relative to gender. Transient atrioventricular block was more frequent in individuals with lower resting heart rate.

Aumento do índice de massa corporal em relação a variáveis clínicas e laboratoriais quanto ao sexo em indivíduos sem evidências de cardiopatia

BACKGROUND In clinical practice, the patients we care for display a wide range of body mass indices, from lean to obese. This finding may be the sole apparent clinical abnormality. OBJECTIVE To evaluate clinical and laboratory variables that might be associated with increased body mass index in asymptomatic men and women with no evidence of heart disease, to provide data to substantiate medical recommendations in a study sample from our everyday practice. METHODS The subjects aged 14 to 74 years (mean 40.6 years), 295 men (43.1%) and 389 women (56.9%) The associations between body mass index stratified by gender and clinical and laboratory variables were analyzed using the Spearman correlation coefficient and multiple linear regression. RESULTS The mean body mass index (BMI) did not differ significantly between women (26.15 Kg/m(2)) and men (26.33 Kg/m(2)). In the multiple linear regression model, the ratios of total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C) (beta = 1.1320; p < 0.001) and serum glucose (beta= 0.0233; p = 0.023) were independently correlated with body mass index in women. In men, the variables independently correlated with BMI were the TC/HDL-C (beta = 0.793; p < 0.001) and age (beta = 0.0464; p = 0.030). CONCLUSION In men and women with no evidence of heart disease, TC/HDL-C increased with body mass index in both genders. Other indices associated with BMI included serum glucose in women and age in men. Clinical and laboratory variables associated with body mass index may differ in relation to gender.

Influence of Parasympathetic Modulation in Doppler Mitral Inflow Velocity in Individuals without Heart Disease

BACKGROUND The relation between left ventricular filing velocities determined by Doppler echocardiography and autonomic nervous system function assessed by heart rate variability (HRV) is unclear. The aim of this study was to evaluate the influence of the autonomic nervous system assessed by the time and frequency domain indices of HRV in the Doppler indices of left ventricular diastolic filling velocities in patients without heart disease. METHODS We studied 451 healthy individuals (255 female [56.4%]) with normal blood pressure, electrocardiogram, chest x-ray, and treadmill electrocardiographic exercise stress test results, with a mean age of 43+/-12 (range 15-82) years, who underwent transthoracic Doppler echocardiography and 24-hour electrocardiographic ambulatory monitoring. We studied indices of HRV on time (standard deviation [SD] of all normal sinus RR intervals during 24 hours, SD of averaged normal sinus RR intervals for all 5-minute segments, mean of the SD of all normal sinus RR intervals for all 5-minute segments, root-mean-square of the successive normal sinus RR interval difference, and percentage of successive normal sinus RR intervals>50 ms) and frequency (low frequency, high frequency, very low frequency, low frequency/high frequency ratio) domains relative to peak flow velocity during rapid passive filling phase (E), atrial contraction (A), E/A ratio, E-wave deceleration time, and isovolumic relaxation time. Statistical analysis was performed with Pearson correlation and logistic regression. RESULTS Peak flow velocity during rapid passive filling phase (E) and atrial contraction (A), E/A ratio, and deceleration time of early mitral inflow did not demonstrate a significant correlation with indices of HRV in time and frequency domain. We found that the E/A ratio was<1 in 45 individuals (10%). Individuals with an E/A ratio<1 had lower indices of HRV in frequency domain (except low frequency/high frequency) and lower indices of the mean of the SD of all normal sinus RR intervals for all 5-minute segments, root-mean-square of the successive normal sinus RR interval difference, and percentage of successive normal sinus RR intervals>50 ms in time domain. Logistic regression demonstrated that an E/A ratio<1 was associated with lower HF. CONCLUSION Individuals with no evidence of heart disease and an E/A ratio<1 demonstrated a significant decrease in indexes of HRV associated with parasympathetic modulation.