Correlation between sympathovagal modulation and functional capacity in pulmonary arterial hypertension patients.

Background: Pulmonary arterial hypertension (PAH) is characterized by sympathovagal imbalance, endothelial dysfunction and progressive remodeling of the pulmonary vasculature that results in heart failure and impairs the functional capacity of patients. In this paper, our aim was to establish correlation among the peripheral endothelial function, the sympathovagal modulation and the functional capacity of PAH patients. Methods: PAH patients performed ultrasound of the brachial artery to peripheral endothelial function evaluation and an electrocardiogram for sympathovagal modulation by spectral analysis. The functional capacity was assessed by cardiopulmonary exercise testing (CPET) and six-minute walking test (6MWT). Results: The sympathovagal modulation, or LF/HF ratio, was correlated with the predicted peak oxygen consumption (peak VO2 %; r=0.692, P Conclusion: PAH patients presented sympathetic modulation predominance, probably due parasympathetic withdraw. The sympathovagal balance was positively correlated with functional parameters showing that despite the increased risk, for surviving, the sympathetic predominance is crucial. On the other hand, no significant correlation was detected between endothelial function versus functional capacity or sympathovagal parameters.