Prognostic significance of exercise plasma noradrenaline levels for cardiac death in patients with mild heart failure.

Abstract

The present study was designed to determine whether exercise plasma noradrenaline (NA) levels could predict cardiac death in patients with mild heart failure in whom the plasma NA levels were only minimally elevated. Treadmill exercise testing with serial measurement of plasma NA and plasma adrenaline were performed in 142 patients with heart failure (New York Heart Association class I-II; age, 58+/-12 years) and 26 age-matched normal subjects. During a median follow-up of 9.6 years, 27 cardiac deaths occurred among the patients. By univariate Cox proportional hazard analysis, left ventricular end-systolic dimension (p<0.001), age (p<0.01), peak exercise heart rate (p<0.01), exercise plasma NA level (p<0.01) and left ventricular ejection fraction (p<0.001) were identified as significant prognostic markers. In a multivariate analysis, exercise plasma NA level was identified as the most powerful prognostic marker (p<0.001), followed by left ventricular end-systolic dimension and peak exercise heart rate. In addition, from the Kaplan-Meier analysis, patients with a supramedian level of exercise plasma NA concentration (NA > or =840pg/ml) had a significantly lower survival rate than those with an inframedian level (p<0.01). Exercise plasma NA levels can provide prognostic information in patients with mild heart failure, which suggests an important role of exercise-induced activation of sympathetic nervous system activity in the prognosis of patients with mild heart failure.