ABSTRACT
FUNDAMENTO: Estudos têm demonstrado que o consumo de oxigênio de pico (VO2 pico) e a inclinação VE/VCO2 são preditores de sobrevida em pacientes com insuficiência cardíaca (IC). Entretanto, com a adição do betabloqueador no tratamento da IC, os valores de prognóstico do VO2 pico e da Inclinação VE/VCO2 não estão totalmente estabelecidos. OBJETIVO: Avaliar o efeito dos betabloqueadores no valor de prognóstico do VO2 pico e da inclinação VE/VCO2 em pacientes com IC. MÉTODOS: Estudamos 391 pacientes com insuficiência cardíaca, com idade de 49 ± 14 anos e fração de ejeção do ventrículo esquerdo de 38 ± 10 por cento. Total de pacientes que usavam (grupo I - GI) e não usavam (grupo II - GII) betabloqueadores: 229 e 162, respectivamente. Todos os pacientes foram submetidos a teste de esforço cardiopulmonar, em esteira, usando o protocolo de Naughton. RESULTADOS: O VO2 pico < 10 ml.kg-1.min-1 identificou pacientes de alto risco, enquanto valores > 16 ml.kg-1.min-1 categorizaram pacientes com melhor prognóstico em médio prazo. A faixa do VO2 pico entre > 10 e < 16 ml.kg-1.min-1 indicou risco moderado para evento cardíaco em quatro anos de seguimento. O betabloqueador reduziu significativamente a inclinação VE/VCO2 em pacientes com IC. O valor prognóstico da inclinação VE/VCO2 < 34 no grupo betabloqueado pode refletir o impacto desse fármaco nessa variável cardiorrespiratória. CONCLUSÃO: O VO2 pico baixo e a inclinação VE/VCO2 elevado são fortes e independentes preditores de eventos cardíacos na insuficiência cardíaca. Assim, ambas as variáveis continuam a ser preditores importantes de sobrevida em pacientes com insuficiência cardíaca, principalmente na era do betabloqueador.
BACKGROUND: Studies have demonstrated that peak oxygen consumption (peak VO2) and the VE/VCO2 slope are predictors of survival in patients with heart failure (HF). However, with the advent of betablockers in the treatment of HF, the prognostic values of peak VO2 and VE/VCO2 slope have not been fully established. OBJECTIVE: To evaluate the effect of betablocker use on the prognostic value of peak VO2 and VE/VCO2 slope in patients with HF. METHODS: We studied 391 patients with heart failure, aged 49 ± 14 years and presenting a left ventricular ejection fraction of 38 ± 10 percent. The total number of patients that used (Group I - GI) or did not use (Group II - GII) betablockers was 229 and 162, respectively. All patients were submitted to a cardiopulmonary stress test on a treadmill, using the Naughton protocol. RESULTS: A peak VO2 < 10 ml.kg-1.min-1 identified high-risk patients, whereas values > 16 ml.kg-1.min-1 categorizes patients with a better mid-term prognosis. Peak VO2 values between > 10 and < 16 ml.kg-1.min-1 indicated moderate risk for cardiac event in four years of follow up. The betablocker use significantly reduced the VE/VCO2 slope in patients with HF. The prognostic value of the VE/VCO2 slope < 34 in the group using betablocker can reflect the impact of the drug on this cardiorespiratory variable. CONCLUSION: A low peak VO2 and an elevated VE/VCO2 slope are strong and independent predictors of cardiac events in HF. Thus, both variables remain important survival predictors in patients with HF, especially at the age of betablockers.
Subject(s)
Female , Humans , Male , Middle Aged , Adrenergic beta-Antagonists/therapeutic use , Carbon Dioxide/metabolism , Exercise Test , Heart Failure/drug therapy , Oxygen Consumption/physiology , Brazil , Epidemiologic Methods , Heart Failure/etiology , Heart Failure/mortality , Heart Rate/physiology , PrognosisABSTRACT
Introdução: O VO2 pico é considerado um importante indicador de prognóstico na IC. O VE/VCO2 slope é uma variável do TCP, que independe do esforço físico e se apresenta também como bom indicador de predição de sobrevida. Porém, é incerta a mudança provocada pelo tratamento de beta bloqueadores sobre os seus valores preditivos de prognóstico em pacientes com IC / The VO2 peak is considered an important indicator of prognosis in HF. The VE/VCO2 slope is a variable of CTP, independent of physical effort, and is a good indicator of survival. However, it is not will established the change the cause of B-blockers may cause on the prognosis predictive values in patients with HF...
Subject(s)
Humans , Male , Female , Exercise , Heart Failure/physiopathology , Adrenergic beta-Antagonists/therapeutic use , Chronic Disease , Control Groups , Lung Volume Measurements/methods , Oxygen Consumption , Predictive Value of Tests , PrognosisABSTRACT
OBJECTIVE: Exercise training programs have been proposed as adjuncts to treatment of heart failure. The effects of a 3-month-exercise-training-program with 3 exercise sessions per week were assessed in patients with stable systolic chronic heart failure. METHODS: We studied 24 patients with final left ventricle diastolic diameter of 70±10mm and left ventricular ejection fraction of 37±4 percent. Mean age was 52±16 years. Twelve patients were assigned to an exercise training group (G1), and 12 patients were assigned to a control group (G2). Patients underwent treadmill testing, before and after exercise training, to assess distance walked, heart rate, systolic blood pressure, and double product. RESULTS: In G2 group, before and after 3 months, we observed, respectively distance walked, 623±553 and 561± 460m (ns); peak heart rate, 142±23 and 146± 33b/min (ns); systolic blood pressure, 154±36 and 164±26 mmHg (ns); and double product, 22211± 6454 and 24293±7373 (ns). In G1 group, before and after exercise, we observed: distance walked, 615±394 and 970± 537m (p<0.003) peak heart rate, 143±24 and 143±29b/min (ns); systolic blood pressure, 136±33 and 133±24 mmHg (ns); and double product, 19907± 7323 and 19115±5776, respectively. Comparing the groups, a significant difference existed regarding the variation in the double product, and in distance walked. CONCLUSION: Exercise training programs in patients with heart failure can bring about an improvement in physical capacity