Enhanced central hypercapnic chemosensitivity is related to autonomic imbalance in patients with heart failure

Abstract

Purpose: The role of central hypercapnic chemosensitivity in autonomic imbalance remains obscure in patients with heart failure. The purpose of this study is to elucidate whether enhanced central hypercapnic chemosensitivity is related to sympathetic activation and parasympathetic withdrawal in this syndrome. Methods: In 40 patients with chronic heart failure, the central hypercapnic chemosensitivity and plasma norepinephrine were measured in the supine resting position. A stationary 6-minute period tracings of blood pressure and electrocardiogram served for measurements of high-frequency(HF) components of heart rate variability and the α-index, the ratio of RR interval and systolic blood pressure variability. Results: The patients with increased sympathetic tone showed a greater chemosensitivity and a resultant augmentation in exercise ventilation. In contrast, the chemosensitivity had an inverse relationship with HF power of heart rate variability (r = −0.38, p < 0.05) and the α-index (r = −0.41, p < 0.01). There were no significant correlations between the hypercapnic chemosensitivity and left ventricular function and between the chemosensitivity and exercise capacity. Conclusions: The enhanced central hypercapnic chemoreflex would potentially underlie autonomic imbalance in patients with chronic heart failure.