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.
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.
Values are reported for the no-BB versus the BB group throughout. Age (57.9 ± 13.3 vs 55.6 ± 12.5), peak V˙O2 (16.2 ± 5.7 vs 16.5 ± 5.5 mL·kg−1·min−1), VE/V˙CO2 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/V˙CO2 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 VE/V˙CO2 slope in the no-BB and BB groups were 36.0 and 34.3, respectively.
The results of the present study indicate that BB does not alter the prognostic value/characteristics of the VE/V˙CO2 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 modern-day clinical practice.
1Department of Physical Therapy, Virginia Commonwealth University, Richmond, VA; 2Cardiopulmonary Laboratory, Cardiology Division, University of Milano, San Paolo Hospital, Milano, ITALY; and 3Cardiology Division, VA Palo Alto Health Care System, Stanford University, Palo Alto, CA
Address for correspondence: Ross Arena, Ph.D., PT, Assistant Professor, Department of Physical Therapy, Box 980224, Virginia Commonwealth University, Health Sciences Campus, Richmond, VA 23298-0224; E-mail: raarena@.vcu.edu.
Submitted for publication July 2006.
Accepted for publication August 2006.