The prognostic value of ventilatory efficiency with beta-blocker therapy in heart failure

ARENA, R. A., M. GUAZZI, J. MYERS, and J. ABELLA. The Prognostic Value of Ventilatory Efficiency with Beta-Blocker Therapy in Heart Failure. Med. Sci. Sports Exerc., Vol. 39, No. 2, pp. 213-219, 2007. Purpose: Beta-blockade (BB) has been shown to improve outcomes among patients with heart failure (HF). The impact this pharmacological approach has on the prognostic information gained from cardiopulmonary exercise testing (CPX) is, however, unclear. Methods: Four hundred seventeen subjects diagnosed with HF underwent CPX. The numbers of subjects prescribed and not prescribed a BB agent were 167 and 250, respectively. Subjects were tracked for cardiac-related mortality after CPX. Results: Values are reported for the no-BB versus the BB group throughout. Age (57.9 +/- 13.3 vs 55.6 +/- 12.5), peak VO2 (16.2 +/- 5.7 vs 16.5 +/- 5.5 mL(.)kg(-1.)min(-1)), VE/VCO2 slope (34.2 +/- 9.0 vs 33.2 +/- 7.4), and peak RER (1.07 +/- 0.16 vs 1.05 +/- 0.14) were similar between groups (P > 0.05). Multivariate Cox regression analysis revealed that the VE/VCO2 slope was the superior predictor of death in both groups (chi-square: 71.9, P < 0.001; and 18.4, P < 0.001). The optimal threshold values for VENCO2 slope in the no-BB and BB groups were 36.0 and 34.3, respectively. Conclusions: The results of the present study indicate that BB does not alter the prognostic value/characteristics of the VE/VCO2 slope. Findings from previous investigations examining the prognostic significance of CPX predominantly using HF groups not receiving a BB agent may, therefore, still be applicable in modem-day clinical practice.