RESUMEN
Abstract Objective: To characterize the behavior of cardiac autonomic modulation in individuals with different times after orthotopic heart transplantation (HTx) using symbolic dynamics analysis. Methods: Sixty patients were evaluated after HTx. We recorded their instantaneous R-R intervals (RRi) by cardiac monitor Polar® RS800CX™ (Polar Electro Oy, Kempele, Finland) for 10 minutes. The same sequence of RRi with 256 consecutive beats was used to perform spectral analysis and symbolic dynamics analysis. We used hierarchical clustering to form groups. One-way analysis of variance (ANOVA) (with Holm-Sidak method) or one-way Kruskal-Wallis test (with Dunn´s post-hoc test) was used to analyze the difference between groups. Linear correlation analysis between variables was performed using Pearson's or Spearman's tests. P-value < 0.05 was considered statistically significant. Results: The 0V% index increased, the 2UV% index and the normalized complexity index decreased with an increase of HTx postoperative time. There were a negative correlation between complexity indexes and 0V% and a positive correlation between complexity indexes and 2UV%. Conclusion: Symbolic dynamics indexes were able to show a specific cardiac autonomic modulation pattern for HTx recipients with different postoperative times.
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Sistema Nervioso Parasimpático/fisiopatología , Sistema Nervioso Simpático/fisiopatología , Trasplante de Corazón/rehabilitación , Dinámicas no Lineales , Corazón/fisiopatología , Periodo Posoperatorio , Valores de Referencia , Factores de Tiempo , Modelos Lineales , Estudios Transversales , Estudios Retrospectivos , Análisis de Varianza , Estadísticas no Paramétricas , Entropía , Frecuencia Cardíaca/fisiologíaRESUMEN
OBJECTIVE: The objective of this study was to investigate the interaction among the determinants of expiratory flow limitation (EFL), peak oxygen uptake (VO2peak), dysanapsis ratio (DR) and age during cycling at different intensities in young and middle-aged men. METHODS: Twenty-two (11 young and 11 middle-aged) men were assessed. Pulmonary function tests (DR), cardiopulmonary exercise tests (VO2peak) and two constant load tests (CLTs) at 75% (moderate intensity) and 125% (high intensity) of the gas exchange threshold were performed to assess EFL. EFL was classified using the percentage of EFL determined from both CLTs (mild: 5%-30%, moderate: 30%-50%, severe: >50%). RESULTS: Only the middle-aged group displayed EFL at both exercise intensities (p<0.05). However, the number of participants with EFL and the percentage of EFL were only associated with age during high-intensity exercise. CONCLUSIONS: There was no interaction between the determinants. However, age was the only factor that was related to the presence of EFL during exercise in the age groups studied.