Abstract 14822: Impact of Proportional Assist Ventilation on Skeletal Muscle Reoxygenation and Central Hemodynamic During Constant Work Rate Exercise in Chronic Heart Failure

Introduction: Progressive chronic heart failure slows the recovery of microvascular oxygen delivery and utilization, which produce deleterious implications to exercise capacity. Respiratory muscle unloading can enhance the responses to exercise thereby allowing a closer matching between skeletal muscle oxygen delivery and utilization in patients with chronic heart failure (CHF). Hypothesis: We reasoned that noninvasive ventilation administered by proportional assisted ventilation (PAV) could accelerate skeletal muscle reoxygenation after high intensity exercise in CHF humans. To test this hypothesis, we conducted a study with 12 patients with stable CHF who were randomized to receive PAV or sham ventilation during high-intensity constant work exercise and compared the effects of these interventions on oxygen pulmonary (O2p), cardiac output and [[Unable to Display Character: ∆]][deoxi-Hb+Mb] off kinetics. Methods: Twelve patients with CHF (NYHA class II and III and left ventricle ejection fraction= 26±9%) underwent two high-intensity, constant-work rate (80% peak) cycle ergometer tests receiving PAV or sham ventilation. Off-exercise kinetics of the primary component of oxygen uptake, an index of fractional oxygen extraction by near infrared spectroscopy (~[[Unable to Display Character: ∆]][deoxy-Hb+Mb]) in the vastus lateralis) and cardiac output (QT) by impedance cardiography were assessed. Results: PAV significantly accelerated the recovery of O2p when compared with sham τ = 56±22 vs. 77±42s, respectively, p<0.05). Interestingly, PAV was associated with faster fractional O2 extraction (~[[Unable to Display Character: ∆]][deoxy-Hb+Mb] by near-infrared spectroscopy) (τ= 31±19 vs. 42±22s, respectively, p<0.05) . In addition, kinetics of QT were significantly faster with PAV than sham (τ = 39±22 vs. 78±46s, respectively, p<0.05). Conclusions: These data indicate that PAV has beneficial effects on recovery of muscle metabolism and central hemodynamics after high-intensity exercise in CHF patients. Financial Support: FAPESP 2009-01842-0

Download Full-text

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.

Download Full-text

Kinetics of oxygen uptake at onset of exercise related to cardiac output, but not to arteriovenous oxygen difference in patients with chronic heart failure

The American Journal of Cardiology ◽

10.1016/s0002-9149(99)00154-x ◽

1999 ◽

Vol 83 (11) ◽

pp. 1573-1576 ◽

Cited By ~ 16

Author(s):

Akihiro Matsumoto ◽

Haruki Itoh ◽

Ikuo Yokoyama ◽

Teruhiko Aoyagi ◽

Seiryo Sugiura ◽

...

Keyword(s):

Heart Failure ◽

Cardiac Output ◽

Chronic Heart Failure ◽

Oxygen Uptake ◽

Kinetics Of ◽

Oxygen Difference

Download Full-text

Limitations of skeletal muscle oxygen delivery and utilization during moderate-intensity exercise in moderately impaired patients with chronic heart failure

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00474.2016 ◽

2016 ◽

Vol 311 (6) ◽

pp. H1530-H1539 ◽

Cited By ~ 5

Author(s):

Victor M. Niemeijer ◽

Ruud F. Spee ◽

Thijs Schoots ◽

Pieter F. F. Wijn ◽

Hareld M. C. Kemps

Keyword(s):

Heart Failure ◽

Skeletal Muscle ◽

Chronic Heart Failure ◽

Near Infrared ◽

Vastus Lateralis ◽

Oxygen Uptake Kinetics ◽

Moderate Intensity ◽

Moderate Intensity Exercise ◽

Exercise Tests ◽

Mean Response Time

The extent and speed of transient skeletal muscle deoxygenation during exercise onset in patients with chronic heart failure (CHF) are related to impairments of local O2 delivery and utilization. This study examined the physiological background of submaximal exercise performance in 19 moderately impaired patients with CHF (Weber class A, B, and C) compared with 19 matched healthy control (HC) subjects by measuring skeletal muscle oxygenation (SmO2) changes during cycling exercise. All subjects performed two subsequent moderate-intensity 6-min exercise tests (bouts 1 and 2) with measurements of pulmonary oxygen uptake kinetics and SmO2 using near-infrared spatially resolved spectroscopy at the vastus lateralis for determination of absolute oxygenation values, amplitudes, kinetics (mean response time for onset), and deoxygenation overshoot characteristics. In CHF, deoxygenation kinetics were slower compared with HC (21.3 ± 5.3 s vs. 16.7 ± 4.4 s, P < 0.05, respectively). After priming exercise (i.e., during bout 2), deoxygenation kinetics were accelerated in CHF to values no longer different from HC (16.9 ± 4.6 s vs. 15.4 ± 4.2 s, P = 0.35). However, priming did not speed deoxygenation kinetics in CHF subjects with a deoxygenation overshoot, whereas it did reduce the incidence of the overshoot in this specific group ( P < 0.05). These results provide evidence for heterogeneity with respect to limitations of O2 delivery and utilization during moderate-intensity exercise in patients with CHF, with slowed deoxygenation kinetics indicating a predominant O2 utilization impairment and the presence of a deoxygenation overshoot, with a reduction after priming in a subgroup, indicating an initial O2 delivery to utilization mismatch.

Download Full-text

Sildenafil improves microvascular O2 delivery-to-utilization matching and accelerates exercise O2 uptake kinetics in chronic heart failure

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00435.2012 ◽

2012 ◽

Vol 303 (12) ◽

pp. H1474-H1480 ◽

Cited By ~ 39

Author(s):

Priscila A. Sperandio ◽

Mayron F. Oliveira ◽

Miguel K. Rodrigues ◽

Danilo C. Berton ◽

Erika Treptow ◽

...

Keyword(s):

Heart Failure ◽

Chronic Heart Failure ◽

Exercise Tolerance ◽

Near Infrared ◽

Vastus Lateralis ◽

Beneficial Effects ◽

Subsequent Response ◽

Constant Work Rate ◽

No Bioavailability ◽

O2 Delivery

Nitric oxide (NO) can temporally and spatially match microvascular oxygen (O2) delivery (Q̇o2mv) to O2 uptake (V̇o2) in the skeletal muscle, a crucial adjustment-to-exercise tolerance that is impaired in chronic heart failure (CHF). To investigate the effects of NO bioavailability induced by sildenafil intake on muscle Q̇o2mv-to-O2 utilization matching and V̇o2 kinetics, 10 males with CHF (ejection fraction = 27 ± 6%) undertook constant work-rate exercise (70–80% peak). Breath-by-breath V̇o2, fractional O2 extraction in the vastus lateralis {∼deoxygenated hemoglobin + myoglobin ([deoxy-Hb + Mb]) by near-infrared spectroscopy}, and cardiac output (CO) were evaluated after sildenafil (50 mg) or placebo. Sildenafil increased exercise tolerance compared with placebo by ∼20%, an effect that was related to faster on- and off-exercise V̇o2 kinetics ( P < 0.05). Active treatment, however, failed to accelerate CO dynamics ( P > 0.05). On-exercise [deoxy-Hb + Mb] kinetics were slowed by sildenafil (∼25%), and a subsequent response “overshoot” ( n = 8) was significantly lessened or even abolished. In contrast, [deoxy-Hb + Mb] recovery was faster with sildenafil (∼15%). Improvements in muscle oxygenation with sildenafil were related to faster on-exercise V̇o2 kinetics, blunted oscillations in ventilation ( n = 9), and greater exercise capacity ( P < 0.05). Sildenafil intake enhanced intramuscular Q̇o2mv-to-V̇o2 matching with beneficial effects on V̇o2 kinetics and exercise tolerance in CHF. The lack of effect on CO suggests that improvement in blood flow to and within skeletal muscles underlies these effects.

Download Full-text

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.

Download Full-text