scholarly journals Central and peripheral factors mechanistically linked to exercise intolerance in heart failure with reduced ejection fraction

2019 ◽  
Vol 317 (2) ◽  
pp. H434-H444 ◽  
Author(s):  
Jesse C. Craig ◽  
Trenton D. Colburn ◽  
Jacob T. Caldwell ◽  
Daniel M. Hirai ◽  
Ayaka Tabuchi ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Function ◽  
Exercise Tolerance ◽  
Critical Speed ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Exercise Intolerance ◽  
Time To Exhaustion ◽  
Central Function ◽  
White Gastrocnemius

Exercise intolerance is a primary symptom of heart failure (HF); however, the specific contribution of central and peripheral factors to this intolerance is not well described. The hyperbolic relationship between exercise intensity and time to exhaustion (speed-duration relationship) defines exercise tolerance but is underused in HF. We tested the hypotheses that critical speed (CS) would be reduced in HF, resting central functional measurements would correlate with CS, and the greatest HF-induced peripheral dysfunction would occur in more oxidative muscle. Multiple treadmill-constant speed runs to exhaustion were used to quantify CS and D′ (distance coverable above CS) in healthy control (Con) and HF rats. Central function was determined via left ventricular (LV) Doppler echocardiography [fractional shortening (FS)] and a micromanometer-tipped catheter [LV end-diastolic pressure (LVEDP)]. Peripheral O2 delivery-to-utilization matching was determined via phosphorescence quenching (interstitial Po2, Po2 is) in the soleus and white gastrocnemius during electrically induced twitch contractions (1 Hz, 8V). CS was lower in HF compared with Con (37 ± 1 vs. 44 ± 1 m/min, P < 0.001), but D′ was not different (77 ± 8 vs. 69 ± 13 m, P = 0.6). HF reduced FS (23 ± 2 vs. 47 ± 2%, P < 0.001) and increased LVEDP (15 ± 1 vs. 7 ± 1 mmHg, P < 0.001). CS was related to FS ( r = 0.72, P = 0.045) and LVEDP ( r = −0.75, P = 0.02) only in HF. HF reduced soleus Po2 is at rest and during contractions (both P < 0.01) but had no effect on white gastrocnemius Po2 is ( P > 0.05). We show in HF rats that decrements in central cardiac function relate directly with impaired exercise tolerance (i.e., CS) and that this compromised exercise tolerance is likely due to reduced perfusive and diffusive O2 delivery to oxidative muscles. NEW & NOTEWORTHY We show that critical speed (CS), which defines the upper boundary of sustainable activity, can be resolved in heart failure (HF) animals and is diminished compared with controls. Central cardiac function is strongly related with CS in the HF animals, but not controls. Skeletal muscle O2 delivery-to-utilization dysfunction is evident in the more oxidative, but not glycolytic, muscles of HF rats and is explained, in part, by reduced nitric oxide bioavailability.

scholarly journals Exercise intolerance in volume overload heart failure is associated with low carotid body mediated chemoreflex drive

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David C. Andrade ◽  
Esteban Díaz-Jara ◽  
Camilo Toledo ◽  
Karla G. Schwarz ◽  
Katherin V. Pereyra ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Function ◽  
Training Program ◽  
Carotid Body ◽  
Exercise Tolerance ◽  
Systolic Function ◽  
Volume Overload ◽  
Exercise Intolerance ◽  
Ventilatory Responses ◽  
Cardiac Systolic Function

AbstractMounting an appropriate ventilatory response to exercise is crucial to meeting metabolic demands, and abnormal ventilatory responses may contribute to exercise-intolerance (EX-inT) in heart failure (HF) patients. We sought to determine if abnormal ventilatory chemoreflex control contributes to EX-inT in volume-overload HF rats. Cardiac function, hypercapnic (HCVR) and hypoxic (HVR) ventilatory responses, and exercise tolerance were assessed at the end of a 6 week exercise training program. At the conclusion of the training program, exercise tolerant HF rats (HF + EX-T) exhibited improvements in cardiac systolic function and reductions in HCVR, sympathetic tone, and arrhythmias. In contrast, HF rats that were exercise intolerant (HF + EX-inT) exhibited worse diastolic dysfunction, and showed no improvements in cardiac systolic function, HCVR, sympathetic tone, or arrhythmias at the conclusion of the training program. In addition, HF + EX-inT rats had impaired HVR which was associated with increased arrhythmia susceptibility and mortality during hypoxic challenges (~ 60% survival). Finally, we observed that exercise tolerance in HF rats was related to carotid body (CB) function as CB ablation resulted in impaired exercise capacity in HF + EX-T rats. Our results indicate that: (i) exercise may have detrimental effects on cardiac function in HF-EX-inT, and (ii) loss of CB chemoreflex sensitivity contributes to EX-inT in HF.

scholarly journals Renal denervation improves cardiac function in rats with chronic heart failure: Effects on expression of β-adrenoceptors

2016 ◽  
Vol 311 (2) ◽  
pp. H337-H346 ◽  
Author(s):  
Hong Zheng ◽  
Xuefei Liu ◽  
Neeru M. Sharma ◽  
Kaushik P. Patel
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Left Ventricle ◽  
Cardiac Function ◽  
Renal Denervation ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Sprague Dawley ◽  
Cardiac Damage ◽  
Sprague Dawley Rats

Chronic activation of the sympathetic drive contributes to cardiac remodeling and dysfunction during chronic heart failure (HF). The present study was undertaken to assess whether renal denervation (RDN) would abrogate the sympathoexcitation in HF and ameliorate the adrenergic dysfunction and cardiac damage. Ligation of the left coronary artery was used to induce HF in Sprague-Dawley rats. Four weeks after surgery, RDN was performed, 1 wk before the final measurements. At the end of the protocol, cardiac function was assessed by measuring ventricular hemodynamics. Rats with HF had an average infarct area >30% of the left ventricle and left ventricular end-diastolic pressure (LVEDP) >20 mmHg. β1- and β2-adrenoceptor proteins in the left ventricle were reduced by 37 and 49%, respectively, in the rats with HF. RDN lowered elevated levels of urinary excretion of norepinephrine and brain natriuretic peptide levels in the hearts of rats with HF. RDN also decreased LVEDP to 10 mmHg and improved basal dP/d t to within the normal range in rats with HF. RDN blunted loss of β1-adrenoceptor (by 47%) and β2-adrenoceptor (by 100%) protein expression and improved isoproterenol (0.5 μg/kg)-induced increase in +dP/d t (by 71%) and −dP/d t (by 62%) in rats with HF. RDN also attenuated the increase in collagen 1 expression in the left ventricles of rats with HF. These findings demonstrate that RDN initiated in chronic HF condition improves cardiac function mediated by adrenergic agonist and blunts β-adrenoceptor expression loss, providing mechanistic insights for RDN-induced improvements in cardiac function in the HF condition.

Involvement of mitogen-activated protein kinases in adriamycin-induced cardiomyopathy

2005 ◽  
Vol 288 (4) ◽  
pp. H1925-H1930 ◽  
Author(s):  
H. Lou ◽  
I. Danelisen ◽  
P. K. Singal
Keyword(s):  
Heart Failure ◽  
Cardiac Function ◽  
Protein Kinases ◽  
Caspase 3 ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Male Rats ◽  
Steady Increase ◽  
Mitogen Activated Protein Kinases ◽  
Mitogen Activated Protein

The current study investigated the phosphorylation of mitogen-activated protein kinases (MAPKs) as well as pro- and anti-apoptotic proteins in adriamycin (ADR)-induced cardiomyopathy (AIC) and heart failure in rats. Modulatory effects of antioxidant probucol on the activation of MAPKs were also examined. Male rats were administered with ADR (15 mg/kg body wt ip, over 2 wk) with and without probucol (120 mg/kg body wt for 4 wk ip). Hearts from these animals were studied at 1- to 24-h as well as at 3-wk posttreatment durations. In the 3-wk group, ADR depressed cardiac function, increased left ventricular end-diastolic pressure (LVEDP), and caused dyspnea and mortality. These changes were prevented by probucol. Phosphorylation of extracellular signal-regulated kinase (ERK)1/2, in the early stage of AIC, showed a biphasic response, with a maximum increase to 513% seen at 4 h, followed by a decrease to 66.8% at 3 wk after the last injection of ADR. Phosphorylation of p38 and c-Jun NH2-terminal kinases (JNKs) showed a steady increase through 2, 4, and 24 h and 3 wk (116% to 148%). In gene microarray analysis at 3 wk (heart failure stage), mRNA expression for both ERK1/2 and p38 kinases was decreased, whereas JNK mRNA was undetectable. Probucol completely prevented these MAPK changes. Activation of caspase-3 as well as the increase in the ratio of Bax to Bcl-xl were seen at early time points (1–24 h) as well as in the heart failure stage (3 wk). It is suggested that a transient increase in ERK1/2 at a shorter interval indicate an early adaptive response, and failure of this response corresponded with heart failure. In contrast, a gradual and persistent increase in p38 and JNK MAPKs as well as in caspase-3 and the Bax-to-Bcl-xl ratio may contribute in the initiation of apoptosis and progression of heart failure. Because probucol modulated changes in cellular signaling pathways and cardiac function, it is likely that oxidative stress plays a key role in AIC and heart failure.

Aging potentiates the effect of congestive heart failure on muscle microvascular oxygenation

2007 ◽  
Vol 103 (5) ◽  
pp. 1757-1763 ◽  
Author(s):  
Bradley J. Behnke ◽  
Michael D. Delp ◽  
David C. Poole ◽  
Timothy I. Musch
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Congestive Heart Failure ◽  
Steady State ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Exercise Intolerance ◽  
Brown Norway ◽  
Phosphorescence Quenching ◽  
Atp Production

Congestive heart failure (CHF) is most prevalent in aged individuals and elicits a spectrum of cardiovascular and muscular perturbations that impairs the ability to deliver (Q̇o2) and utilize (V̇o2) oxygen in skeletal muscle. Whether aging potentiates the CHF-induced alterations in the Q̇o2-to-V̇o2 relationship [which determines microvascular Po2 (PmvO2)] in resting and contracting skeletal muscle is unclear. We tested the hypothesis that old rats with CHF would demonstrate a greater impairment of skeletal muscle PmvO2 than observed in young rats with CHF. Phosphorescence quenching was utilized to measure spinotrapezius PmvO2 at rest and across the rest-to-contractions (1-Hz, 4–6 V) transition in young (Y) and old (O) male Fischer 344 Brown-Norway rats with CHF induced by myocardial infarction (mean left ventricular end-diastolic pressure >20 mmHg for YCHF and OCHF). In CHF muscle, aging significantly reduced resting PmvO2 (32.3 ± 3.4 Torr for YCHF and 21.3 ± 3.3 Torr for OCHF; P < 0.05) and in both YCHF and OCHF compared with their aged-matched counterparts, CHF reduced the rate of the PmvO2 fall at the onset of contractions. Moreover, across the on-transient and in the subsequent steady state, PmvO2 values in OCHF vs. YCHF were substantially lower (for steady-state, 20.4 ± 1.7 Torr for YCHF and 16.4 ± 2.0 Torr for OCHF; P < 0.05). At rest and during contractions in CHF, the pressure driving blood-muscle O2 diffusion (PmvO2) is substantially decreased in old animals. This finding suggests that muscle dysfunction and exercise intolerance in aged CHF patients might be due, in part, to the failure to maintain a sufficiently high PmvO2 to facilitate blood-muscle O2 exchange and support mitochondrial ATP production.

Exercise training attenuates the pressor response evoked by peripheral chemoreflex in rats with heart failure

2016 ◽  
Vol 94 (9) ◽  
pp. 979-986 ◽  
Author(s):  
Leonardo Calegari ◽  
Bruna B. Mozzaquattro ◽  
Douglas D. Rossato ◽  
Edson Quagliotto ◽  
Janaina B. Ferreira ◽  
...  
Keyword(s):  
Heart Failure ◽  
Exercise Training ◽  
Cardiac Function ◽  
Diastolic Pressure ◽  
Pressor Response ◽  
Potassium Cyanide ◽  
Left Ventricular ◽  
Treadmill Running ◽  
Chemoreflex Sensitivity ◽  
Peripheral Chemoreflex

The effects of exercise training (ExT) on the pressor response elicited by potassium cyanide (KCN) in the rat model of ischemia-induced heart failure (HF) are unknown. We evaluated the effects of ExT on chemoreflex sensitivity and its interaction with baroreflex in rats with HF. Wistar rats were divided into four groups: trained HF (Tr-HF), sedentary HF (Sed-HF), trained sham (Tr-Sham), and sedentary sham (Sed-Sham). Trained animals underwent to a treadmill running protocol for 8 weeks (60 m/day, 5 days/week, 16 m/min). After ExT, arterial pressure (AP), baroreflex sensitivity (BRS), peripheral chemoreflex (KCN: 100 μg/kg body mass), and cardiac function were evaluated. The results demonstrate that ExT induces an improvement in BRS and attenuates the pressor response to KCN relative to the Sed-HF group (P < 0.05). The improvement in BRS was associated with a reduction in the pressor response following ExT in HF rats (P < 0.05). Moreover, ExT induced a reduction in left ventricular end-diastolic pressure and pulmonary congestion compared with the Sed-HF group (P < 0.05). The pressor response to KCN in the hypotensive state is decreased in sedentary HF rats. These results suggest that ExT improves cardiac function and BRS and attenuates the pressor response evoked by KCN in HF rats.

scholarly journals Effects of 3-Month Astaxanthin Supplementation on Cardiac Function in Heart Failure Patients with Left Ventricular Systolic Dysfunction-A Pilot Study

Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1896 ◽  
Author(s):  
Takao Kato ◽  
Takatoshi Kasai ◽  
Akihiro Sato ◽  
Sayaki Ishiwata ◽  
Shoichiro Yatsu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Heart Failure ◽  
Pilot Study ◽  
Cardiac Function ◽  
Exercise Tolerance ◽  
Systolic Dysfunction ◽  
Cardiac Contractility ◽  
Antioxidant Properties ◽  
Left Ventricular ◽  
Reactive Oxygen Metabolite

Astaxanthin has strong antioxidant properties. We conducted a prospective pilot study on heart failure (HF) patients with left ventricular (LV) systolic dysfunction to investigate improvements in cardiac function and exercise tolerance in relation to suppression of oxidative stress by 3-month astaxanthin supplementation. Oxidative stress markers—serum Diacron reactive oxygen metabolite (dROM), biological antioxidant potential (BAP), and urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) concentrations, LV ejection fraction (LVEF), and 6-min walk distance (6MWD) were assessed before and after 3-month astaxanthin supplementation. Finally, the data of 16 HF patients were analyzed. Following 3-month astaxanthin supplementation, dROM level decreased from 385.6 ± 82.6 U.CARR to 346.5 ± 56.9 U.CARR (p = 0.041) despite no changes in BAP and urinary 8-OHdG levels. LVEF increased from 34.1 ± 8.6% to 38.0 ± 10.0% (p = 0.031) and 6MWD increased from 393.4 ± 95.9 m to 432.8 ± 93.3 m (p = 0.023). Significant relationships were observed between percent changes in dROM level and those in LVEF. In this study, following 3-month astaxanthin supplementation, suppressed oxidative stress and improved cardiac contractility and exercise tolerance were observed in HF patients with LV systolic dysfunction. Correlation between suppression of oxidative stress and improvement of cardiac contractility suggests that suppression of oxidative stress by astaxanthin supplementation had therapeutic potential to improve cardiac functioning.

Direct Myocardial Implantation of Human Fetal Stem Cells in Heart Failure Patients: Long-term Results

2010 ◽  
Vol 13 (1) ◽  
pp. 31 ◽  
Author(s):  
Federico Benetti ◽  
Ernesto Pe�herrera ◽  
Teodoro Maldonado ◽  
Yan Duarte Vera ◽  
Valvanur Subramanian ◽  
...  
Keyword(s):  
Heart Failure ◽  
Stem Cells ◽  
Cardiac Function ◽  
Nyha Class ◽  
Left Ventricular ◽  
Long Term Results ◽  
Walk Test ◽  
The Mean ◽  
6 Minute Walk Test ◽  
Minute Walk

Background: End-stage heart failure (HF) is refractory to current standard medical therapy, and the number of donor hearts is insufficient to meet the demand for transplantation. Recent studies suggest autologous stem cell therapy may regenerate cardiomyocytes, stimulate neovascularization, and improve cardiac function and clinical status. Although human fetal-derived stem cells (HFDSCs) have been studied for the treatment of a variety of conditions, no clinical studies have been reported to date on their use in treating HF. We sought to determine the efficacy and safety of HFDSC treatment in HF patients.Methods and Results: Direct myocardial transplantation of HFDSCs by open-chest surgical procedure was performed in 10 patients with HF due to nonischemic, nonchagasic dilated cardiomyopathy. Before and after the procedure, and with no changes in their preoperative doses of medications (digoxin, furosemide, spironolactone, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, betablockers), patients were assessed for New York Heart Association (NYHA) class, performance in the exercise tolerance test (ETT), ejection fraction (EF), left ventricular end-diastolic dimension (LVEDD) via transthoracic echocardiography, performance in the 6-minute walk test, and performance in the Minnesota congestive HF test. All 10 patients survived the operation. One patient had a stroke 3 days after the procedure, and although she later recovered, she was unable to perform the follow-up tests. Another male patient experienced pericardial effusion 3 weeks after the procedure. Although it resolved spontaneously, the patient abandoned his control tests and died 5 months after the procedure. An autopsy of the myocardium suggested that new young cells were present in the cardiomyocyte mix. At 40 months, the mean (SD) NYHA class decreased from 3.4 0.5 to 1.33 0.5 (P = .001); the mean EF increased 31%, from 26.6% 4% to 34.8% 7.2% (P = .005); and the mean ETT increased 291.3%, from 4.25 minutes to 16.63 minutes (128.9% increase in metabolic equivalents, from 2.46 to 5.63) (P < .0001); the mean LVEDD decreased 15%, from 6.85 0.6 cm to 5.80 0.58 cm (P < .001); mean performance in the 6-minute walk test increased by 43.2%, from 251 113.1 seconds to 360 0 seconds (P = .01); the mean distance increased 64.4%, from 284.4 144.9 m to 468.2 89.8 m (P = .004); and the mean result in the Minnesota test decreased from 71 27.3 to 6 5.9 (P < .001).Conclusion: Although these initial findings suggest direct myocardial implantation of HFDSCs is feasible and improves cardiac function in HF patients at 40 months, more clinical research is required to confirm these observations.

Estimation of Left Ventricular Wall Stiffness by Analysis of Late Diastolic Pressure Components

2011 ◽  
Author(s):  
Casandra L. Niebel ◽  
Kelley C. Stewart ◽  
Takahiro Ohara ◽  
John J. Charonko ◽  
Pavlos P. Vlachos ◽  
...  
Keyword(s):  
Heart Failure ◽  
Left Ventricle ◽  
Diastolic Dysfunction ◽  
Diastolic Pressure ◽  
Left Ventricular Diastolic Dysfunction ◽  
Left Ventricular ◽  
Ventricular Wall ◽  
Ventricular Relaxation ◽  
Wall Stiffness ◽  
Ventricular Diastolic Dysfunction

Left ventricular diastolic dysfunction (LVDD) is any abnormality in the filling of the left ventricle and is conventionally evaluated by analysis of the relaxation driven phase, or early diastole. LVDD has been shown to be a precursor to heart failure and the diagnosis and treatment for diastolic failure is less understood than for systolic failure. Diastole consists of two filling waves, early and late and is primarily dependent on ventricular relaxation and wall stiffness.

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