The relationship between heart rate reserve and oxygen uptake reserve in heart failure patients on optimized and non-optimized beta-blocker therapy
Clinics
; 63(6): 725-730, 2008. graf, tab
Article
em En
| LILACS
| ID: lil-497882
Biblioteca responsável:
BR1.1
ABSTRACT
BACKGROUND:
The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients either on non-optimized or off beta-blocker therapy is known to be unreliable. The aim of this study was to evaluate the relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients receiving optimized and non-optimized beta-blocker treatment during a treadmill cardiopulmonary exercise test.METHODS:
A total of 27 sedentary heart failure patients (86 percent male, 50±12 years) on optimized beta-blocker therapy with a left ventricle ejection fraction of 33±8 percent and 35 sedentary non-optimized heart failure patients (75 percent male, 47±10 years) with a left ventricle ejection fraction of 30±10 percent underwent the treadmill cardiopulmonary exercise test (Naughton protocol). Resting and peak effort values of both the percentage of oxygen consumption reserve and percentage of heart rate reserve were, by definition, 0 and 100, respectively.RESULTS:
The heart rate slope for the non-optimized group was derived from the points 0.949±0.088 (0 intercept) and 1.055±0.128 (1 intercept), p<0.0001. The heart rate slope for the optimized group was derived from the points 1.026±0.108 (0 intercept) and 1.012±0.108 (1 intercept), p=0.47. Regression linear plots for the heart rate slope for each patient in the non-optimized and optimized groups revealed a slope of 0.986 (almost perfect) for the optimized group, but the regression analysis for the non-optimized group was 0.030 (far from perfect, which occurs at 1).CONCLUSION:
The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in patients on optimized beta-blocker therapy was reliable, but this relationship was unreliable in non-optimized heart failure patients.Palavras-chave
Texto completo:
1
Índice:
LILACS
Assunto principal:
Consumo de Oxigênio
/
Propanolaminas
/
Carbazóis
/
Antagonistas Adrenérgicos beta
/
Insuficiência Cardíaca
/
Frequência Cardíaca
Tipo de estudo:
Guideline
Limite:
Female
/
Humans
/
Male
Idioma:
En
Revista:
Clinics
Assunto da revista:
MEDICINA
Ano de publicação:
2008
Tipo de documento:
Article