Previous studies demonstrated that oscillatory pattern (LFMSNA/HFMSNA) and arterial baroreflex control (ABRMSNA) of muscle sympathetic nerve activity (MSNA) are impaired in chronic systolic heart failure (CHF). The purpose of the study was to test the hypothesis that exercise training would improve the LFMSNA/HFMSNA, and the gain and time delay of ABRMSNA in CHF patients. Twenty-six CHF patients, NYHA Functional Class II-III, EF≤40%, peak VO2≤20ml/kg/min were divided into two groups: untrained (UT, n=13, 57±3 years) and exercise-trained (ET, n=13, 49±3 years). MSNA was directly recorded by microneurography technique. Arterial pressure was measured on a beat-to-beat basis. Time series of MSNA and systolic arterial pressure were analyzed by autoregressive spectral analysis. Gain and time delay of ABRMSNA was obtained by bivariate autoregressive analysis. Exercise training was performed on a cycle ergometer at moderate intensity, three 60-min sessions per week for 16 weeks. Baseline MSNA, LFMSNA/HFMSNA, gain and time delay of ABRMSNA were similar between groups. The gain and time delay of ABRMSNA were unchanged in the ET patients. In contrast, the gain of the ABRMSNA was significantly reduced (Δ= 0.5±0.5 vs. -1.7 ±0.6, a.u./mmHg, P=0.01) and the time delay of ABRMSNA was significantly increased (Δ= -1.3±1.2 vs. 3.3±0.9 s, P=0.01) in UT patients. MSNA was significantly lower (Δ= 15±5 vs. 0±3 bursts/100 heart beats, P=0.02) and LFMSNA/HFMSNA significantly increased (Δ= 0.3±0.1 vs. -0.3±0.2, P=0.04) in ET patients compared with UT patients. Exercise training prevents the deterioration in the oscillatory pattern and ABRMSNA in CHF patients.
- Chronic heart failure
- sympathetic modulation
- arterial baroreflex control
- exercise training
- Copyright © 2014, American Journal of Physiology - Heart and Circulatory Physiology