Blood flow distribution within skeletal muscle during exercise in the presence of chronic heart failure: effect of milrinone.

We sought to determine whether the normal inspiratory intrathoracic pressures (PITP) produced during exercise contribute to the blunted cardiac output and locomotor limb blood flow responses observed in chronic heart failure (CHF). Five chronically instrumented dogs exercised on a treadmill at 2.5 mile/h at 5% grade while healthy or after the induction of tachycardia-induced CHF. We observed several key differences in the cardiovascular responses to changes in the inspiratory PITP excursion between health and CHF; namely, 1) removing ∼70% of the normally produced inspiratory PITP excursion during exercise (with 15 cmH2O inspiratory positive pressure ventilation) significantly reduced stroke volume (SV) in healthy animals by 5 ± 2% ( P < 0.05) but significantly increased SV and cardiac output (QTOT) in animals with CHF by 5 ± 1% ( P < 0.05); 2) doubling the magnitude of the inspiratory PITP excursion had no effect on SV or QTOT in healthy animals but significantly reduced steady-state QTOT and SV in animals with CHF by −4 ± 3% and −10 ± 3%, respectively; 3) removing the majority of the normally produced inspiratory PITP excursion had no effect on blood flow distribution in healthy animals but increased hindlimb blood flow (9 ± 3%, P < 0.05) out of proportion to the increases in QTOT; and 4) the only similarity between healthy and CHF animals was that increasing the inspiratory PITP excursion significantly reduced steady-state locomotor limb blood flow by 5 ± 2% and 6 ± 3%, respectively ( P < 0.05 for both). We conclude that 1) the normally produced inspiratory PITP excursions are required for a maximal SV response to submaximal exercise in healthy animals but detrimental to the SV and QTOT responses to submaximal exercise in CHF, 2) the respiratory muscle ergoreflex tonically restrains locomotor limb blood flow during submaximal exercise in CHF, and 3) excessive inspiratory muscle work further compromises cardiac function and blood flow distribution in both health and CHF.

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Modeling of Oxygen Transport to Skeletal Muscle: Blood Flow Distribution, Shunt, and Diffusion

Advances in Experimental Medicine and Biology - Oxygen Transport to Tissue XIII ◽

10.1007/978-1-4615-3404-4_1 ◽

1992 ◽

pp. 3-10 ◽

Cited By ~ 5

Author(s):

Johannes Piiper

Keyword(s):

Skeletal Muscle ◽

Blood Flow ◽

Oxygen Transport ◽

Muscle Blood Flow ◽

Flow Distribution ◽

Blood Flow Distribution ◽

Skeletal Muscle Blood Flow ◽

And Diffusion

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Metabolic abnormality of calf skeletal muscle is improved by localised muscle training without changes in blood flow in chronic heart failure

Heart ◽

10.1136/hrt.78.5.437 ◽

1997 ◽

Vol 78 (5) ◽

pp. 437-443 ◽

Cited By ~ 25

Author(s):

M. Ohtsubo ◽

K. Yonezawa ◽

H. Nishijima ◽

K. Okita ◽

A. Hanada ◽

...

Keyword(s):

Heart Failure ◽

Skeletal Muscle ◽

Blood Flow ◽

Chronic Heart Failure ◽

Metabolic Abnormality ◽

Muscle Training

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Exercise Capacity, Skeletal Muscle Strength and Blood Flow following Exercise Rehabilitation in Chronic Heart Failure

Clinical Science ◽

10.1042/cs088018p ◽

1995 ◽

Vol 88 (s32) ◽

pp. 18P-18P

Author(s):

TP Chua ◽

S McKinlay ◽

M Volterrani ◽

J Toman ◽

AJS Coats

Keyword(s):

Heart Failure ◽

Skeletal Muscle ◽

Blood Flow ◽

Chronic Heart Failure ◽

Muscle Strength ◽

Exercise Capacity ◽

Exercise Rehabilitation ◽

Skeletal Muscle Strength

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Effects of chronic heart failure on skeletal muscle capillary hemodynamics at rest and during contractions

Journal of Applied Physiology ◽

10.1152/japplphysiol.00308.2003 ◽

2003 ◽

Vol 95 (3) ◽

pp. 1055-1062 ◽

Cited By ~ 88

Author(s):

Troy E. Richardson ◽

Casey A. Kindig ◽

Timothy I. Musch ◽

David C. Poole

Keyword(s):

Heart Failure ◽

Skeletal Muscle ◽

Blood Flow ◽

Chronic Heart Failure ◽

Muscle Function ◽

Muscle Blood Flow ◽

Rat Skeletal Muscle ◽

Exercise Onset ◽

Final Response ◽

Microscopy Techniques

Chronic heart failure (CHF) reduces muscle blood flow at rest and during exercise and impairs muscle function. Using intravital microscopy techniques, we tested the hypothesis that the speed and amplitude of the capillary red blood cell (RBC) velocity ( VRBC) and flux (FRBC) response to contractions would be reduced in CHF compared with control (C) spinotrapezius muscle. The proportion of capillaries supporting continuous RBC flow was less ( P < 0.05) in CHF (0.66 ± 0.04) compared with C (0.84 ± 0.01) muscle at rest and was not significantly altered with contractions. At rest, VRBC (C, 270 ± 62; CHF, 179 ± 14 μm/s) and FRBC (C, 22.4 ± 5.5 vs. CHF, 15.2 ± 1.2 RBCs/s) were reduced (both P < 0.05) in CHF vs. C muscle. Contractions significantly (both P < 0.05) elevated VRBC (C, 428 ± 47 vs. CHF, 222 ± 15 μm/s) and FRBC (C, 44.3 ± 5.5 vs. CHF, 24.0 ± 1.2 RBCs/s) in C and CHF muscle; however, both remained significantly lower in CHF than C. The time to 50% of the final response was slowed (both P < 0.05) in CHF compared with C for both VRBC (C, 8 ± 4; CHF, 56 ± 11 s) and FRBC (C, 11 ± 3; CHF, 65 ± 11 s). Capillary hematocrit increased with contractions in C and CHF muscle but was not different ( P > 0.05) between CHF and C. Thus CHF impairs diffusive and conductive O2 delivery across the rest-to-contractions transition in rat skeletal muscle, which may help explain the slowed O2 uptake on-kinetics manifested in CHF patients at exercise onset.

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Dynamic regulation of leg vasomotor tone in patients with chronic heart failure

Journal of Applied Physiology ◽

10.1152/jappl.1991.71.3.1070 ◽

1991 ◽

Vol 71 (3) ◽

pp. 1070-1075 ◽

Cited By ~ 10

Author(s):

M. J. Sullivan ◽

F. R. Cobb

Keyword(s):

Heart Failure ◽

Skeletal Muscle ◽

Blood Flow ◽

Cardiac Output ◽

Chronic Heart Failure ◽

Left Ventricular ◽

Work Rate ◽

Vasomotor Tone ◽

Leg Blood Flow ◽

Leg Exercise

We examined the central hemodynamic (n = 5) and leg blood flow (n = 9) responses to one- and two-leg bicycle exercise in nine ambulatory patients with chronic heart failure due to left ventricular systolic dysfunction (ejection fraction 17 +/- 9%). During peak one- vs. two-leg exercise, leg blood flow (thermodilution) tended to be higher (1.99 +/- 0.91 vs. 1.67 +/- 0.91 l/min, P = 0.07), whereas femoral arteriovenous oxygen difference was lower (13.6 +/- 3.1 vs. 15.0 +/- 2.9 ml/dl, P less than 0.01). Comparison of data from exercise stages matched for single-leg work rate during one- vs. two-leg exercise demonstrated that cardiac output was similar while both oxygen consumption and central arteriovenous oxygen differences were lower, indicating relative improvement in the cardiac output response at a given single-leg work rate during one-leg exercise. This was accompanied by higher leg blood flow (1.56 +/- 0.76 vs. 1.83 +/- 0.72 l/min, P = 0.02) and a tendency for leg vascular resistance to be lower (92 +/- 54 vs. 80 +/- 48 Torr.l-1.min, P = 0.08) without any change in blood lactate. These data indicate that, in patients with chronic heart failure, leg vasomotor tone is dynamically regulated, independent of skeletal muscle metabolism, and is not determined solely by intrinsic abnormalities in skeletal muscle vasodilator capacity. Our results suggest that relative improvements in central cardiac function may lead to a reflex release of skeletal muscle vasoconstrictor tone in this disorder.

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Beneficial haemodynamic effects of insulin in chronic heart failure

Heart ◽

10.1136/hrt.85.5.508 ◽

2001 ◽

Vol 85 (5) ◽

pp. 508-513

Author(s):

W A Parsonage ◽

D Hetmanski ◽

A J Cowley

Keyword(s):

Heart Failure ◽

Skeletal Muscle ◽

Blood Flow ◽

Cardiac Output ◽

Chronic Heart Failure ◽

Insulin Infusion ◽

Muscle Blood Flow ◽

Haemodynamic Effects ◽

High Dose ◽

Skeletal Muscle Blood Flow

OBJECTIVETo characterise the central and regional haemodynamic effects of insulin in patients with chronic heart failure.DESIGNSingle blind, placebo controlled study.SETTINGUniversity teaching hospital.PATIENTSTen patients with stable chronic heart failure.INTERVENTIONSHyperinsulinaemic euglycaemic clamp and non-invasive haemodynamic measurements.MAIN OUTCOME MEASURESChange in resting heart rate, blood pressure, cardiac output, and regional splanchnic and skeletal muscle blood flow.RESULTSInsulin infusion led to a dose dependent increase in skeletal muscle blood flow of 0.36 (0.13) and 0.73 (0.14) ml/dl/min during low and high dose insulin infusions (p < 0.05 and p < 0.005 v placebo, respectively). Low and high dose insulin infusions led to a fall in heart rate of 4.6 (1.4) and 5.1 (1.3) beats/min (p < 0.05 and p < 0.005 v placebo, respectively) and a modest increase in cardiac output. There was no significant change in superior mesenteric artery blood flow.CONCLUSIONIn patients with chronic heart failure insulin is a selective skeletal muscle vasodilator that leads to increased muscle perfusion primarily through redistribution of regional blood flow rather than by increased cardiac output. These results provide a rational haemodynamic explanation for the apparent beneficial effects of insulin infusion in the setting of heart failure.

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