Effects of carvedilol on oxygen uptake and heart rate kinetics in patients with chronic heart failure at simulated altitude
Articolo
Data di Pubblicazione:
2012
Citazione:
Effects of carvedilol on oxygen uptake and heart rate kinetics in patients with chronic heart failure at simulated altitude / M. Karsten, M. Contini, C. Cefalù, G. Cattadori, P. Palermo, A. Apostolo, M. Bussotti, D. Magrì, E. Salvioni, S. Farina, S. Sciomer, A.M. Catai, P. Agostoni. - In: EUROPEAN JOURNAL OF PREVENTIVE CARDIOLOGY. - ISSN 2047-4873. - 19:3(2012 Jun), pp. 444-451. [10.1177/1741826711402736]
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 ( $${\stackrel{\cdot }{\hbox{ V }}\hbox{ O }}_{2}$$ ) and heart rate (HR) on-kinetics at constant workload were assessed calculating the time constant (τ) with a monoexponential equation. $${\stackrel{\cdot }{\hbox{ V }}\hbox{ O }}_{2}$$ 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 $${\stackrel{\cdot }{\hbox{ V }}\hbox{ O }}_{2}$$ 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 betablockade. The higher τ of $${\stackrel{\cdot }{\hbox{ V }}\hbox{ O }}_{2}$$ 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% $${\stackrel{\cdot }{\hbox{ V }}\hbox{ O }}_{2}$$ increase without trouble at the beginning of exercise when treated with carvedilol.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
M. Karsten, M. Contini, C. Cefalù, G. Cattadori, P. Palermo, A. Apostolo, M. Bussotti, D. Magrì, E. Salvioni, S. Farina, S. Sciomer, A.M. Catai, P. Agostoni
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