Maximal exercise capacity and oxygen consumption of lambs with an aortopulmonary left-to-right shunt

1990 ◽  
Vol 69 (4) ◽  
pp. 1479-1485 ◽  
Author(s):  
J. W. Gratama ◽  
J. J. Meuzelaar ◽  
M. Dalinghaus ◽  
J. H. Koers ◽  
A. J. Werre ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Exercise Capacity ◽  
Maximal Exercise ◽  
Left Ventricular ◽  
Peak Oxygen Consumption ◽  
Systemic Blood ◽  
Systemic Blood Flow ◽  
Ventricular Performance ◽  
Left Ventricular Output ◽  
Maximal Exercise Capacity

We determined maximal exercise capacity and measured hemodynamics in 10 6-wk-old lambs with an aortopulmonary left-to-right shunt [S, 57 +/- 11%, (SD)] and in 9 control lambs (C) during a graded treadmill test 8 days after surgery. Maximal exercise capacity (3.7 +/- 0.2 km/h and 10 +/- 5% inclination vs. 4.0 +/- 0.9 km/h and 15 +/- 0% inclination, P less than 0.02) and peak oxygen consumption (25 +/- 7 vs. 34 +/- 8 ml O2.min-1.kg-1, P less than 0.02) were both lower in the shunt than in the control lambs. This was due to a lower maximal systemic blood flow in the shunt lambs (271 +/- 38 vs. 359 +/- 71 ml.min-1.kg-1, P less than 0.01). Despite their high maximal left ventricular output, which was higher than in the control lambs (448 +/- 87 vs. 359 +/- 71 ml.min-1.kg-1, P less than 0.05), the left-to-right shunt could not be compensated for during maximal exercise because of a decreased reserve in heart rate (S: 183 +/- 22 to 277 +/- 38 beats/min; C: 136 +/- 25 to 287 +/- 29 beats/min) and in left ventricular stroke volume (S: 1.8 +/- 0.3 to 1.6 +/- 0.4 ml/kg; C: 1.0 +/- 0.3 to 1.3 +/- 0.2 ml/kg). We conclude that exercise capacity of shunt lambs is lower than that of control lambs, despite a good left ventricular performance, because a part of the reserves for increasing the left ventricular output is already utilized at rest.

scholarly journals Assessing Maximal Exercise Capacity: Peak Work or Peak Oxygen Consumption?

2013 ◽  
Vol 59 (1) ◽  
pp. 90-96 ◽  
Author(s):  
D. A. Kaminsky ◽  
A. Knyazhitskiy ◽  
A. Sadeghi ◽  
C. G. Irvin
Keyword(s):  
Oxygen Consumption ◽  
Exercise Capacity ◽  
Maximal Exercise ◽  
Peak Oxygen Consumption ◽  
Maximal Exercise Capacity

GABAergic modulation of ventilation and peak oxygen consumption in obese Zucker rats

2001 ◽  
Vol 90 (5) ◽  
pp. 1707-1713 ◽  
Author(s):  
Shin-Da Lee ◽  
Hitoshi Nakano ◽  
Gaspar A. Farkas
Keyword(s):  
Exercise Capacity ◽  
Maximal Exercise ◽  
Peak Oxygen Consumption ◽  
Zucker Rats ◽  
Inhibitory Neurotransmitter ◽  
Endogenous Gaba ◽  
Obese Rats ◽  
Obese Zucker Rats ◽  
Gabaergic Modulation ◽  
Maximal Exercise Capacity

Obesity is often associated with a reduced ventilatory response and a decreased maximal exercise capacity. GABA is a major inhibitory neurotransmitter in the mammalian central nervous system. Altered GABAergic mechanisms have been detected in obese Zucker rats and implicated in their hyperphagic response. Whether altered GABAergic mechanisms also contribute to regulate ventilation and influence exercise capacity in obese Zucker rats is unknown and formed the basis of the present study. Eight lean [317 ± 18 (SD) g] and eight obese (450 ± 27 g) Zucker rats were studied at 12 wk of age. Ventilation at rest and ventilation during hypoxic (10% O2) and hypercapnic (4% CO2) challenges were measured by the barometric method. Peak O2 consumption (V˙o 2 peak) in response to a progressive treadmill test to exhaustion was measured in a metabolic treadmill. Ventilation and V˙o 2 peak were assessed after administration of equal volumes of DMSO (vehicle) and the GABAA receptor antagonist bicuculline (1 mg/kg). In lean animals, bicuculline administration had no effect on ventilation andV˙o 2 peak. In obese rats, bicuculline administration significantly ( P < 0.05) increased resting ventilation (465 ± 53 and 542 ± 72 ml · kg−1 · min−1 for control and bicuculline, respectively), ventilation during exposure to hypoxia (899 ± 148 and 1,038 ± 83 ml · kg−1 · min−1 for control and bicuculline, respectively), andV˙o 2 peak (62 ± 3.7 and 67 ± 3.5 ml · kg−0.75 · min−1 for control and bicuculline, respectively). However, in obese Zucker rats, ventilation in response to hypercapnia did not change after bicuculline administration (608 ± 96 vs. 580 ± 69 ml · kg−1 · min−1). Our findings indicate that endogenous GABA depresses ventilation and limits exercise performance in obese Zucker rats.

TO FIND OUT CORRELATION BETWEEN SVC FLOW AND LEFT VENTRICULAR OUTPUT IN NEWBORN BETWEEN GESTATIONAL AGE OF 34-37 WEEKS AND >37 WEEKS ON LIFE DAY ONE

2020 ◽  
Vol 4 (6) ◽  
Author(s):  
Mukesh Kumar Dhaker ◽  
Kapil Kumar Tak ◽  
Suresh Verma
Keyword(s):  
Blood Flow ◽  
Gestational Age ◽  
Preterm Neonate ◽  
Left Ventricular ◽  
Preterm Newborn ◽  
Systemic Blood ◽  
Systemic Blood Flow ◽  
Medical College ◽  
Left Ventricular Output ◽  
R Value

Background: Preterm newborn is vulnerable to brain injury which is thought to be caused partly by abnormalities in cerebral perfusion (1). Commonly used parameters such as blood pressure & blood lactate level are not sufficient to detect low circulatory blood flow in preterm neonate  because these are poor surrogate markers of systemic blood flow during the circulatory transition just after birth Methods- The Present Prospective Cross sectional observational study was conducted in the department of Paediatrics, attached to DR.SN Medical College Jodhpur over the duration of one year .Ethical consent was taken from local institutional ethical committee of Dr.S.N Medical College Jodhpur. Results: In present study 2D Echocardiography was done in preterm newborn  (Median  gestational age 35 week) (range 34-37 week ) on life day one for measurement of superior vena cava blood flow in which mean flow was 62.5±20.93 ml/kg/min (Mean±SD) and Median flow was  57.83ml/kg/min  and  range of SVC flow was  18-143 ml/kg/min. Also measured left ventricular output on life day one  in which Mean±SD and median LVO  flow was 204.88±70.74  and 189.5 which show r value 0.56 with significant positive predictive value <0.0001 by Pearson’s correlation  coefficient. In term newborn between gestational ages of 37-41 week with Median gestational age 39 week (range 37-41 week) on life day one. In which mean LVO flow was 203.31± 61.88 (Mean±SD)   and mean SVC flow was 58.89±19.11, (Mean±SD) Shows r value 0.40 and positive predictive value < 0.002 by using Pearson’s correlation coefficient. Conclusion: We conclude that SVC flow measurent through 2D colour Doppler echocardiography is most reliable and non-invasive method in preterm newborn as well as evaluation of treatment. . Although echocardiographic assessment of LVO appears to be relatively robust, it is of limited clinical value preterm neonates   in the   neonatal unit setting because the majority of sick preterm neonate will have patent ductus arteriosus, meaning that LVO does not represent systemic blood flow and is in fact a better marker of pulmonary flow volume. Keywords: SVC, Preterm, Term neonates.

scholarly journals Left ventricular regional function and maximal exercise capacity in aortic stenosis

2015 ◽  
Vol 17 (2) ◽  
pp. 217-224 ◽  
Author(s):  
R. Dulgheru ◽  
J. Magne ◽  
L. Davin ◽  
A. Nchimi ◽  
C. Oury ◽  
...  
Keyword(s):  
Aortic Stenosis ◽  
Exercise Capacity ◽  
Maximal Exercise ◽  
Left Ventricular ◽  
Regional Function ◽  
Maximal Exercise Capacity

scholarly journals Cardiovascular risk associated with long-term anabolic-androgenic steroid abuse: an observational study from Norway

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
T Saetereng ◽  
P Vanberg ◽  
K Steine ◽  
D Atar ◽  
S Halvorsen
Keyword(s):  
Exercise Capacity ◽  
Ventricular Arrhythmias ◽  
Maximal Exercise ◽  
Left Ventricular ◽  
Control Group ◽  
User Group ◽  
Exercise Ecg ◽  
Cardiovascular Evaluation ◽  
Maximal Exercise Capacity

Abstract Background The use of anabolic-androgenic steroids (AAS) has become highly prevalent among recreational weightlifters. Numerous case reports have suggested an association between AAS use and a vast range of different cardiovascular diseases, including sudden cardiac death (SCD) and coronary artery disease (CAD). Few clinical studies have evaluated the risk of SCD and the prevalence of CAD in individuals with long-term AAS use. Purpose To evaluate the risk of ventricular arrhythmias and the prevalence of CAD among men with long-term AAS use. Methods Strength-trained men with at least three years of cumulative AAS use were recruited from recreational gyms. The control group consisted of strength-trained competing athletes who self-reported never using any performance enhancing drugs (non-users). AAS use was verified by sophisticated blood and urine analyses. Study participants went through a comprehensive cardiovascular evaluation including exercise ECG, 24 h ECG, heart rate variability (HRV) measures, signal averaged ECG (SAECG) and QT dispersion (QTd). Coronary computed tomography angiography (CCTA) was performed in AAS users. Not all participants had all tests. Results We included 51 AAS users and 21 non-users. Median age (25th-75th percentile) was 33 (29–37) years in the user group and 33 (29–42) years in the non-user group. Forty-eight (94%) of the users had been using AAS for five years or more. Characteristics are presented in the table. AAS users had significantly lower HDL values compared to non-users (p&lt;0.001). No signs of ischemia or arrhythmias were detected during exercise ECG, however maximal exercise capacity was lower than in the control group and also compared to age-standardized values. A considerable, but statistically non-significant reduction was seen in overall HRV estimated as the standard deviation of the RR intervals for normal sinus beats (SDNN) (p=0.05). No difference was seen regarding left ventricular late potentials or QTd (table). Eight (19%) of the forty-two AAS users undergoing CCTA had at least a mild degree of CAD, and four of them three-vessel disease. Conclusion No ECG-findings indicated an increased risk of ventricular arrhythmias among the long-term AAS users. However, their maximal exercise capacity was lower than in controls, and one fifth of the long-term AAS users had verified CAD on CT coronary angiography. FUNDunding Acknowledgement Type of funding sources: None. Table 1

Sign in / Sign up

Export Citation Format

Share Document