Is the algorithm used to process heart rate variability data clinically relevant? Analysis in male adolescents

OBJECTIVE: To analyze whether the algorithm used for the heart rate variability assessment (fast Fourier transform versus autoregressive methods) influenced its association with cardiovascular risk factors in male adolescents. METHODS: This cross-sectional study included 1,152 male adolescents (aged 14 to 19 years). The low frequency, high frequency components (absolute numbers and normalized units), low frequency/high frequency ratio, and total power of heart rate variability parameters were obtained using the fast Fourier transform and autoregressive methods, while the adolescents were resting in a supine position. RESULTS: All heart rate variability parameters calculated from both methods were different (p<0.05). However, a low effect size (<0.1) was found for all parameters. The intra-class correlation between methods ranged from 0.96 to 0.99, whereas the variation coefficient ranged from 7.4 to 14.8%. Furthermore, waist circumference was negatively associated with high frequency, and positively associated with low frequency and sympatovagal balance (p<0.001 for both fast Fourier transform and autoregressive methods in all associations). Systolic blood pressure was negatively associated with total power and high frequency, whereas it was positively associated with low frequency and sympatovagal balance (p<0.001 for both fast Fourier transform and autoregressive methods in all associations). Body mass index was negatively associated with high frequency, while it was positively associated with low frequency and sympatovagal balance (p values ranged from <0.001 to 0.007). CONCLUSION: There are significant differences in heart rate variability parameters obtained with the fast Fourier transform and autoregressive methods in male adolescent; however, these differences are not clinically significant. OBJETIVO: Analisar se o algoritmo usado para avaliação da variabilidade da frequência cardíaca (transformada rápida de Fourier versus autoregressivo) influencia em sua associação com fatores de risco cardiovascular adolescentes do gênero masculino. MÉTODOS: Estudo transversal, que incluiu 1.152 adolescentes do gênero masculino (14 a 19 anos). Componentes de baixa e alta frequência (absolutos e unidades normalizadas), razão componente de baixa frequência/componente de alta frequência e poder total da variabilidade da frequência cardíaca foram obtidos em repouso, na posição supina, usando os métodos transformada rápida de Fourier e autorregressivo. RESULTADOS: Todos os parâmetros da variabilidade da frequência cardíaca para ambos os métodos foram diferentes (p<0,05). Entretanto, um pequeno tamanho do efeito (<0,1) foi observado para todos os parâmetros. Os coeficientes de correlação intraclasse entre os métodos variaram de 0,96 a 0,99, enquanto os coeficientes de variação foram de 7,4 a 14,8%. A circunferência abdominal foi negativamente associada com o componente de alta frequência, e positivamente associada com o componente de baixa frequência e o balanço simpatovagal (p<0,001 para a transformada rápida de Fourier e o autorregressivo em todas as associações). A pressão arterial sistólica foi negativamente associada com o poder total e o componente de alta frequência, enquanto foi positivamente associada com o componente de baixa frequência e o balanço simpatovagal (p<0,001 para a transformada rápida de Fourier e o autorregressivo em todas as associações). O índice de massa corporal foi negativamente associado com o componente de alta frequência, enquanto foi positivamente associado com o componente de baixa frequência e o balanço simpatovagal (valores de p variando de <0,001 a 0,007). CONCLUSÃO: Houve diferenças significantes nos parâmetros da variabilidade da frequência cardíaca obtidos com os métodos transformada rápida de Fourier e autorregressivo em adolescentes masculinos, mas essas diferenças não foram clinicamente significativas

Impact of hypertension on arterial stiffness and cardiac autonomic modulation in patients with peripheral artery disease: a cross-sectional study

To examine the impact of hypertension on cardiovascular health in patients with symptomatic peripheral artery disease and to identify factors associated with uncontrolled hypertension. A cross-sectional study including 251 patients with symptomatic peripheral artery disease (63.9% males, mean age 67±10 years). Following hypertension diagnosis, blood pressure was measured to determine control of hypertension. Arterial stiffness (carotid-femoral pulse wave velocity) and cardiac autonomic modulation (sympathovagal balance) were assessed. Hypertension was associated with higher carotid-femoral pulse wave velocity, regardless of sex, age, ankle-brachial index, body mass index, walking capacity, heart rate, or comorbidities (ß=2.59±0.76m/s, b=0.318, p=0.003). Patients with systolic blood pressure ≥120mmHg had higher carotid-femoral pulse wave velocity values than normotensive individuals, and hypertensive patients with systolic blood pressure of ≤119mmHg (normotensive: 7.6±2.4m/s=≤119mmHg: 8.1±2.2m/s 120-129mmHg:9.8±2.6m/s=≥130mmHg: 9.9±2.9m/s, p0.05). Hypertensive patients with symptomatic peripheral artery disease have increased arterial stiffness. Arterial stiffness is even greater in patients with uncontrolled high blood pressure

Treinamento aeróbio não altera pressão arterial de mulheres menopausadas e com síndrome metabólica

FUNDAMENTO: A Hipertensão arterial (HA) é uma condição tanto agravante quanto agravada pela Síndrome Metabólica (SM). A menopausa pode tornar o tratamento da hipertensão mais difícil porque é uma condição que favorece a piora nos componentes da SM. Embora existam evidências de que o treinamento com exercícios físicos reduza a pressão arterial, se as condições da menopausa e da SM afetam os benefícios induzidos pelo exercício é algo ainda não evidenciado. OBJETIVO: Comparar os efeitos do treinamento aeróbio na pressão arterial entre mulheres com SM não menopausadas e menopausadas. MÉTODOS: Foram recrutadas 44 mulheres divididas em quatro grupos experimentais: controle não menopausada (CNM: 39,5 ± 1,1 anos, n = 11); controle menopausada (CM: 54,9 ± 1,7 anos, n = 12); aeróbio não menopausada (ANM: 43,1 ± 2,1 anos, n = 11) e aeróbio menopausada (AM: 52,1 ± 1,6 anos, n = 10). Os grupos de exercício realizaram treinamento aeróbio durante três meses, cinco vezes por semana, com intensidade entre 60% e 70% da frequência cardíaca de reserva. A pressão arterial de repouso e a resposta pressórica clínica após 60 minutos de exercício foram medidas antes e após o período treinamento. O teste de ANOVA de dois fatores foi usado, considerando p 0,05). CONCLUSÃO: Três meses de treinamento aeróbio melhora componentes da SM, mas não altera a pressão arterial de repouso, nem a resposta pressórica aguda após uma sessão de exercício aeróbio em mulheres com SM

Effect of rest interval on cardiovascular responses after resistance exercise

OBJECTIVE: To analyze the acute effect of rest interval length on cardiovascular response after resistance exercise. METHODS: Twenty young eutrophic men (23.9 ± 0.7 years;23.8 ± 0.5 kg/m²) performed two experimental sessions in a random order: resistance exercise with a 30-second (I30) and with a 90-second (I90) rest interval between sets. Both sessions included five exercises with 50% of the one-repetition maximum. Before and 24 hours after the experimental sessions, systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and rate-pressure product (RPP) were obtained. RESULTS: The SBP, DBP and RPP responses were similar between the I30 and I90 sessions (p&gt;0.05), while the HR after I30 was significantly higher than after I90 (p<0.01) for the first hour after exercise. The cardiovascular responses during the first 24 hours were similar between both sessions (p&gt;0.05). CONCLUSION: Different recovery intervals did not promote post-exercise hypotension, however, a short rest interval increases heart rate for 1 hour after exercise. In addition, within 24 hours of the responses were similar between groups

Association between handgrip strength and vascular function in patients with hypertension

Background: Increased handgrip strength has been associated with lower cardiovascular and non-cardiovascular mortality in different populations. In patients with hypertension, arterial stiffness relates to cardiovascular mortality. However, whether muscle strength is associated with arterial stiffness in hypertensives is unknown. Thus, the objective of this study was to analyze the association between handgrip strength and arterial stiffness parameters in hypertensive patients. Methods: Seventy-two hypertensive patients completed all evaluations and were included in the analysis. The ambulatory arterial stiffness index (AASI) was obtained based on 24-h ambulatory blood pressure monitoring. Carotid-femoral pulse wave velocity (cfPWV), and reflected wave indicator (AIx and AIx@75) were estimated using applanation tonometry technique, whereas handgrip strength test was performed using a digital dynamometer. Crude and adjusted linear regression models were performed. Results: The crude analysis revealed a negative association between handgrip strength and AASI (b = −0.41, p = 0.002) and AIx (b = −0.49, p  0.05). Conclusion: Handgrip strength is negatively associated with AASI and AIx@75, but not with AIx and cfPWV in hypertensive patients

Validation of a Brazilian Portuguese Version of the Walking Estimated-Limitation Calculated by History (WELCH)

Abstract Background: The Walking Estimated-Limitation Calculated by History (WELCH) questionnaire has been proposed to evaluate walking impairment in patients with intermittent claudication (IC), presenting satisfactory psychometric properties. However, a Brazilian Portuguese version of the questionnaire is unavailable, limiting its application in Brazilian patients. Objective: To analyze the psychometric properties of a translated Brazilian Portuguese version of the WELCH in Brazilian patients with IC. Methods: Eighty-four patients with IC participated in the study. After translation and back-translation, carried out by two independent translators, the concurrent validity of the WELCH was analyzed by correlating the questionnaire scores with the walking capacity assessed with the Gardner treadmill test. To determine the reliability of the WELCH, internal consistency and test–retest reliability with a seven-day interval between the two questionnaire applications were calculated. Results: There were significant correlations between the WELCH score and the claudication onset distance (r = 0.64, p = 0.01) and total walking distance (r = 0.61, p = 0.01). The internal consistency was 0.84 and the intraclass correlation coefficient between questionnaire evaluations was 0.84. There were no differences in WELCH scores between the two questionnaire applications. Conclusion: The Brazilian Portuguese version of the WELCH presents adequate validity and reliability indicators, which support its application to Brazilian patients with IC