Heart Failure–Specific Relationship Between Muscle Sympathetic Nerve Activity and Aortic Wave Reflection

ABSTRACT Background Reflected arterial waves contribute to left ventricular (LV) afterload. Heart failure patients with reduced ejection fraction (HFrEF) are afterload sensitive and sympathetically activated. We tested the hypothesis that HFrEF patients exhibit a positive relationship between sympathetic vasoconstrictor discharge and aortic wave reflection. Methods Sixteen treated patients with HFrEF (61 ± 9years of age, left ventricular ejection fraction 30 ± 7%, 3 women) and 16 similar-aged healthy control subjects (57 ± 7years of age, 4 women) underwent noninvasive measurements of radial pulse waveforms (applanation tonometry) to calculate central blood pressures and aortic wave reflection characteristics: augmentation pressure (AP), augmentation index (AI x ), and AI x corrected to a heart rate of 75beats/min (AI x @75). Muscle sympathetic nerve activity (MSNA) burst frequency was recorded from the fibular nerve (microneurography). Results HFrEF patients had higher AI x (26 ± 9vs 17 ± 15%; P P P  = 0.05). There were no between-group differences in heart rate, other measures of blood pressure (brachial and central; P > .05), AP (11 ± 5vs 7 ± 8mm Hg; P  = 0.11), or AI x @75 (19 ± 9vs 13 ± 11%,- P  = 0.14). MSNA correlated positively with AP ( r  = 0.50; P x ( r  = 0.51; P x @75 ( r  = 0.54; P r  = 0.002–0.18; P  > 0.49). Conclusions In patients with HFrEF, but not similarly aged healthy subjects, indices of aortic wave reflection correlate positively with MSNA. By increasing LV afterload, such neurovascular coupling could impair LV performance and worsen heart failure symptoms. Therapies that attenuate neurogenic vasoconstriction may benefit HFrEF patients by diminishing arterial wave reflection.