TY - JOUR
T1 - Influence of the Metaboreflex on Pulmonary Vascular Capacitance in Heart Failure
AU - Van Iterson, Erik H.
AU - Snyder, Eric M.
AU - Johnson, Bruce D.
AU - Olson, Thomas P.
N1 - Funding Information:
This work was supported by the American Heart Association grant 12GRNT1160027 (T. P. O.), National Center for Advancing TranslationalScience grant KL2TR000136 (T. P. O.).
Publisher Copyright:
© 2015 by the American College of Sports Medicine.
PY - 2016/3/1
Y1 - 2016/3/1
N2 - Purpose An impaired metaboreflex is associated with abnormal ventilatory and peripheral vascular function in heart failure (HF), whereas its influence on cardiac function or pulmonary vascular pressure remains unclear. We aimed to assess whether metabolite-sensitive neural feedback (metaboreflex) from locomotor muscles via postexercise regional circulatory occlusion (RCO) attenuates pulmonary vascular capacitance (GXCAP) and/or circulatory power (CircP) in patients with HF. Methods Eleven patients with HF (NYHA class, I/II; ages, 51 ± 15 yr; ejection fraction, 32% ± 9%) and 11 age-and gender-matched controls (ages, 43 ± 9 yr) completed three cycling sessions (4 min, 60% peak oxygen uptake (VO2)). Session 1 was a control trial including normal recovery (NR). Session 2 or 3 included bilateral upper thigh pressure tourniquets inflated suprasystolic at end of exercise (RCO) for 2-min recovery with or without inspired CO2 (RCO + CO2) (randomized). Mean arterial pressure, HR, and VO2 were continuously measured. Estimates of central hemodynamics; CircP = (VO2 × mean arterial pressure)/weight; oxygen pulse index (O2pulseI = (VO2/HR)/body surface area); and GXCAP = O2pulseI × end-tidal partial pressure CO2 were calculated. Results At rest and end of exercise, CircP and GXCAP were lower in HF versus those in controls (P < 0.05), with no differences between transients (P > 0.05). At 2-min recovery, GXCAP was lower during RCO versus that during NR in both groups (72 ± 23 vs 98 ± 20 and 73 ± 34 vs 114 ± 35 mL·beat-1·mm Hg·m-2, respectively; P < 0.05), whereas CircP did not differ between transients (P > 0.05). Differences (% and Δ) between baseline and 2-min recovery among transients suggest that metaboreflex attenuates GXCAP in HF. Differences (% and Δ) between baseline and 2-min recovery among transients suggest that metaboreflex may attenuate CircP in controls. Conclusions The present observations suggest that locomotor muscle metaboreflex activation may influence CircP in controls but not in HF. However, metaboreflex activation may evoke decreases in GXCAP (increased pulmonary vascular pressures) in HF and controls.
AB - Purpose An impaired metaboreflex is associated with abnormal ventilatory and peripheral vascular function in heart failure (HF), whereas its influence on cardiac function or pulmonary vascular pressure remains unclear. We aimed to assess whether metabolite-sensitive neural feedback (metaboreflex) from locomotor muscles via postexercise regional circulatory occlusion (RCO) attenuates pulmonary vascular capacitance (GXCAP) and/or circulatory power (CircP) in patients with HF. Methods Eleven patients with HF (NYHA class, I/II; ages, 51 ± 15 yr; ejection fraction, 32% ± 9%) and 11 age-and gender-matched controls (ages, 43 ± 9 yr) completed three cycling sessions (4 min, 60% peak oxygen uptake (VO2)). Session 1 was a control trial including normal recovery (NR). Session 2 or 3 included bilateral upper thigh pressure tourniquets inflated suprasystolic at end of exercise (RCO) for 2-min recovery with or without inspired CO2 (RCO + CO2) (randomized). Mean arterial pressure, HR, and VO2 were continuously measured. Estimates of central hemodynamics; CircP = (VO2 × mean arterial pressure)/weight; oxygen pulse index (O2pulseI = (VO2/HR)/body surface area); and GXCAP = O2pulseI × end-tidal partial pressure CO2 were calculated. Results At rest and end of exercise, CircP and GXCAP were lower in HF versus those in controls (P < 0.05), with no differences between transients (P > 0.05). At 2-min recovery, GXCAP was lower during RCO versus that during NR in both groups (72 ± 23 vs 98 ± 20 and 73 ± 34 vs 114 ± 35 mL·beat-1·mm Hg·m-2, respectively; P < 0.05), whereas CircP did not differ between transients (P > 0.05). Differences (% and Δ) between baseline and 2-min recovery among transients suggest that metaboreflex attenuates GXCAP in HF. Differences (% and Δ) between baseline and 2-min recovery among transients suggest that metaboreflex may attenuate CircP in controls. Conclusions The present observations suggest that locomotor muscle metaboreflex activation may influence CircP in controls but not in HF. However, metaboreflex activation may evoke decreases in GXCAP (increased pulmonary vascular pressures) in HF and controls.
KW - CARDIAC POWER
KW - CIRCULATORY POWER
KW - ERGORECEPTOR
KW - MECHANORECEPTOR
KW - METABORECEPTOR
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U2 - 10.1249/MSS.0000000000000775
DO - 10.1249/MSS.0000000000000775
M3 - Article
C2 - 26414317
AN - SCOPUS:84958857621
SN - 0195-9131
VL - 48
SP - 353
EP - 362
JO - Medicine and science in sports and exercise
JF - Medicine and science in sports and exercise
IS - 3
ER -