The prognostic value of the cardiopulmonary exercise test in patients with heart failure who have been treated with beta-blockers

Abstract

The prevalence of chronic heart failure and a reduced ejection fraction (CHF-REF) has increased over the last decade. The cardiopulmonary exercise test (CPET) is an established tool for managing these patients. For patients who are administered beta-blockers, its predictive value is debated. The aim of this study was to assess the prognostic values of several parameters in patients with CHF-REF who were on beta-blockers. 390 patients with CHF-REF underwent CPET after cardiac rehabilitation and were followed for two years. The primary endpoints were all-cause mortality, cardiac-related mortality and major cardiovascular events (hospitalization for HF, heart transplantation and acute coronary syndrome or arrhythmia). The mean beta-blockers dosage was 68.9% of the target dose. The two-year mortality rate was 13%, while the mean age of the population was 57.1 years. In addition, most of the patients were men (85.5% vs. 14.5%). The resting LVEF was 35.7 ± 9.4 and the maximal oxygen uptake (peak VO₂) was 19.5 ml/kg/min. The peak VO₂, VE/VCO₂ slope and circulatory power were significant predictors of risk. The prognosis was better when the initial linear VE/VCO₂ slope was lower than 30, and the final steeper VE/VCO₂ slope was lower than 32. There was no difference between the two slopes. The oxygen uptake efficiency slope, oxygen uptake, heart rate recovery, VE/VCO₂/VO₂ index and ventilatory threshold had no prognostic value. The peak VO₂, circulatory power and VE/VCO₂ slope were prognostic indicators for patients with CHF-REF who were on beta-blockers.