Clinical InvestigationRight and Left Ventricular FunctionLeft Ventricular Adaptation to Acute Hypoxia: A Speckle-Tracking Echocardiography Study
Section snippets
Study Population
Twenty-one participants (mean age, 27 ± 7 years) were studied in normoxia, in hypoxia, and in normoxia after atropine administration. In a second stage, 10 subjects (five of whom were new participants; mean age, 26 ± 7 years) were studied in normoxia and in hypoxia under β-blockade, and six of these subjects were also studied in normoxia under β-blockade.
Inclusion criteria were as follows: age 20 to 40 years; normal results on physical examination, 12-lead electrocardiography, and standard
Effect of Normobaric Hypoxia
Clinical characteristics of the subjects are shown in Table 1. The mean age of the subjects was of 27 ± 7 years (seven men, 14 women), and the mean body surface area was 1.73 ± 0.16 m2. Compared with normoxia, hypoxic breathing decreased SaO2 (as expected), increased HR, and did not alter BP. There was a small decrease in Pco2.
Discussion
The present results show that hypoxic breathing increases LV performance in healthy subjects and that this effect is explained by hypoxia-induced systemic vasodilation rather than by associated autonomic nervous system changes.
Conclusions
Using STE, we demonstrated an increase in LV function during acute hypoxia. The increases in the magnitudes of myocardial deformation parameters were only marginally explained by hypoxia-induced tachycardia. The increased deformation magnitude persisted in hypoxia under β-blockade, consistent with the role of an intrinsic mechanism unrelated to catecholaminergic activation and suggesting a contribution for hypoxia-induced systemic vasodilation in the observed changes in LV function.
Acknowledgments
We thank G. Deboeck and M. Lamotte for their helpful contributions.
References (49)
- et al.
Echocardiographic and tissue Doppler imaging of cardiac adaptation to high altitude in native highlanders versus acclimatized lowlanders
Am J Cardiol
(2009) Physiological adaptation of the cardiovascular system to high altitude
Prog Cardiovasc Dis
(2010)- et al.
Differentiation between pathologic and physiologic left ventricular hypertrophy by tissue Doppler assessment of long-axis function in patients with hypertrophic cardiomyopathy or systemic hypertension and in athletes
Am J Cardiol
(2001) - et al.
A novel feature-tracking echocardiographic method for the quantitation of regional myocardial function: validation in an animal model of ischemia-reperfusion
J Am Coll Cardiol
(2008) - et al.
Stress Doppler echocardiography for identification of susceptibility to high altitude pulmonary edema
J Am Coll Cardiol
(2000) - et al.
From adrenoceptor mechanisms to clinical therapeutics: Raymond Ahlquist, Ph.D. 1914-1983
J Am Coll Cardiol
(1984) - et al.
Recommendations for chamber quantification: a report from the American Society of Echocardiography's Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. American Society of Echocardiography's Guidelines and Standards Committee; European Association of Echocardiography
J Am Soc Echocardiogr
(2005) - et al.
Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior vena cava
Am J Cardiol
(1990) - et al.
Evaluation of various empirical formulas for estimating mean pulmonary artery pressure by using systolic pulmonary artery pressure in adults
Chest
(2009) - et al.
A simple method for noninvasive estimation of pulmonary vascular resistance
J Am Coll Cardiol
(2003)
Current and evolving echocardiographic techniques for the quantitative evaluation of cardiac mechanics: ASE/EAE consensus statement on methodology and indications endorsed by the Japanese Society of Echocardiography
J Am Soc Echocardiogr
Augmentation of left ventricular torsion with exercise is attenuated with age
J Am Soc Echocardiogr
Effect of aging on twist-displacement loop by 2-dimensional speckle tracking imaging
J Am Soc Echocardiogr
Strain rate imaging: why do we need it?
J Am Coll Cardiol
Direct evidence of changes in myofilament responsiveness to Ca2+ during hypoxia and reoxygenation in myocardium
Am J Physiol
Myocyte adaptation to chronic hypoxia and development of tolerance to subsequent acute severe hypoxia
Circ Res
Depressed myocardial function in the goat at high altitude
J Appl Physiol
Operation Everest III (Comex '97): modifications of cardiac function secondary to altitude-induced hypoxia. An echocardiographic and Doppler study
Am J Respir Crit Care Med
The effect of 18 h of simulated high altitude on left ventricular function
Eur J Appl Physiol
Impact of acute hypoxic pulmonary hypertension on LV diastolic function in healthy mountaineers at high altitude
Am J Physiol Heart Circ Physiol
Catecholamines in plasma and urine at high altitude
J Appl Physiol
The autonomic nervous system at high altitude
Clin Auton Res
Acclimatization to high altitude increases muscle sympathetic activity both at rest and during exercise
Am J Physiol Regulat Integrat Comp Physiol
Arterial pressure and muscle sympathetic nerve activity are increased after two hours of sustained but not cyclic hypoxia in healthy humans
J Appl Physiol
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2018, Journal of the American Society of EchocardiographyCitation Excerpt :Of note, our results contrast with earlier 2D echocardiography studies of LV torsion during hypoxia and/or high altitude34,35 that showed increased torsion. However, these studies either involved short-term (90 minutes) isolated hypoxia with only very mild increases in pulmonary pressure34 or exposure to high altitude lasting 10 days35 that could potentially allow for high-altitude acclimatization and thus for compensatory mechanisms to increase torsion. With regards to possible compensatory mechanism, it should be noted that in our study on D4 torsion tended to be increased relative to D3, whereas systolic LV eccentricity tended to be decreased relative to D3, suggesting that high-altitude acclimatization effects were starting to take place.
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This work was supported by Fonds Erasme, Université Libre de Bruxelles (Brussels, Belgium) (Dr. Dedobbeleer); Fonds Pour la Chirurgie Cardiaque (Brussels, Belgium) (Drs. Dedobbeleer and Unger); Fonds Docteur et Madame René Tagnon (King Baudouin Foundation, Brussels, Belgium) (Dr. Dedobbeleer); and Fondation M. Horlait-Dapsens King (Brussels, Belgium) (Dr. Dedobbeleer).