Abstract | BACKGROUND: The response to moderate exercise at altitude in heart failure (HF) is unknown. METHODS AND RESULTS: We evaluated 30 HF patients, (NYHA I-III, 25 M/5 F; 59 ± 10 years; LVEF = 39.6 ± 7.1%), in stable clinical conditions, treated with carvedilol at the maximal tolerated dose. We performed a maximal cardiopulmonary exercise test ( CPET) with ramp protocol at sea level to evaluate patients' performance and two moderate intensity constant workload CPETs (50% of peak workload) at sea level (normoxia) and simulated altitude (hypoxia). Oxygen uptake (.VO2 ) and heart rate (HR) on-kinetics at constant workload were assessed calculating the time constant (τ) with a monoexponential equation. .VO2 and HR were higher in hypoxia (0.944 ± 0.233 vs 1.031 ± 0.264 l/min; 100 ± 23 vs 108 ± 22 bpm; p < 0.001). On-kinetics showed a different behavior of τ being .VO2 faster in hypoxia (67.1 ± 23.0 vs. 56.3 ± 19.7 s; p = 0.026) and HR faster in normoxia (49.3 ± 19.4 vs. 62.2 ± 22.5 s; p = 0.018). Ten patients, who lowered oxygen kinetics in hypoxia, had greater HR increase during maximal CPET suggesting lower functional beta-blockade. The higher τ of .VO2 in hypoxia is likely to be due to a peripheral effect of carvedilol mediated either by β- or α-receptor. CONCLUSION: HF patients performing moderate exercise at 2000 m simulated altitude have 20% .VO2 increase without trouble at the beginning of exercise when treated with carvedilol.
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Authors | Marlus Karsten, Mauro Contini, Claudia Cefalù, Gaia Cattadori, Pietro Palermo, Anna Apostolo, Maurizio Bussotti, Damiano Magrì, Elisabetta Salvioni, Stefania Farina, Susanna Sciomer, Aparecida Maria Catai, Piergiuseppe Agostoni |
Journal | European journal of preventive cardiology
(Eur J Prev Cardiol)
Vol. 19
Issue 3
Pg. 444-51
(Jun 2012)
ISSN: 2047-4881 [Electronic] England |
PMID | 21450573
(Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Adrenergic Antagonists
- Carbazoles
- Propanolamines
- Carvedilol
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Topics |
- Adrenergic Antagonists
(therapeutic use)
- Aged
- Altitude
- Carbazoles
(therapeutic use)
- Carvedilol
- Chronic Disease
- Exercise Test
- Female
- Heart Failure
(diagnosis, drug therapy, metabolism, physiopathology)
- Heart Rate
(drug effects)
- Humans
- Hypoxia
(metabolism, physiopathology)
- Kinetics
- Male
- Middle Aged
- Myocardium
(metabolism)
- Oxygen Consumption
(drug effects)
- Propanolamines
(therapeutic use)
- Treatment Outcome
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