Exercício respiratório lento: um possível modulador autonômico em indivíduos com insuficiência cardíaca

Abstract

Heart failure is described as a cardiac dysfunction that promotes inadequate blood supply to tissue metabolic demand resulting in impaired functional performance. The literature reports evidence that autonomic dysfunction could suffer slow respiratory exercise intervention (SBE) and could be estimated by analysis of heart rate variability (HRV). Therefore, this review intends to evaluate the SBE as a possible modulator of autonomic activity adjunct in the rehabilitation process of patients with heart failure. The literature review was performed from the first record until July 2012, in databases: Medline, SciELO, IBCS, LILACS, and Google Scholar, using the following terms: "heart failure", "breathing-control", "respiratory exercise "," slow breathing "," device-guided breathing "," slow respiration "," paced breathing "," breathing exercise "," exercise respiration "," exercise respiration slow, "" slow breathing exercise "," breathing pattern "," heart rate variability "," chaos theory ", as well as translations of the corresponding terms in different combinations. The search yielded a total of 268 articles, 237 being excluded by reading the title or abstract, 22 repeated, and seven did not assess the outcome of interest. From the selected studies, 15 references/citations were consulted and two related studies in this review were added. Only four articles met the inclusion/exclusion criteria as being three transverse and one longitudinal observational. HRV during the rest was reduced in HF patients when compared to healthy subjects. In transverse analyzes the SBE improved HRV total by increased parasympathetic activation in both groups, but were most healthy individuals benefit when compared to patients with heart failure. The longitudinal study suggests that the benefits of sympathovagal balance would be greater in patients with better functional NYHA class (New York Heart Association) and left ventricular ejection fraction. Further studies are needed to determine the effects of training with SBE as a modulator of autonomic activity in this population.