Correlation between heart rate index, SBPpeak-to-SBPrest ratio and peak oxygen consumption in patients with chronic heart failure

Abstract

Objective: To investigate the correlation between heart rate index (HRI), systolic blood pressure(SBP) peak-to-SBPrest ratio (SBPR) and peak oxygen consumption (peakVO2) in patients with chronic heart failure (CHF), and discuss the possibility of using HRI and SBPR collected during exercise to assess the exercise tolerance of CHF patients in the absence of gas analysis. Methods: In this cross-sectional study, a total of 547 patients with CHF who underwent cardiopulmonary exercise test(CPET) in Tongji Hospital Heart Rehabilitation Center Affiliated to Tongji University from March 2007 to December 2018 were collected retrospectively, focusing on their clinical data including age, gender, type of heart failure,BMI as well as data collected during their CPETs, such as peakVO2, HRI and SBPR. Spearman univariate correlation analysis was used for statistical analysis, to unveil the correlations between peakVO2 and those parameters, and multiple linear regression analysis was also conducted. Results: A total of 547 CHF patients conducting CPET were included in this research, of which 447 were male, at age of 63(56, 69). Univariate analysis indicates that HRI, SBPR and peakVO2 showed significant positive correlation (r=0.323, 0.263, respectively, all P<0.001); Age and peak VO2 showed significant negative correlation(r=-0.207, P<0.001); Male patients showed peakVO2 higher than female(r=-0.229, P<0.001); PeakVO2 of heart failure with reduced ejection fraction(HFrEF) was lower than heart failure with mid-range ejection fraction(HFmrEF)and heart failure with preserved ejection fraction(HFpEF) (r=0.181, P<0.001). Body mass index (BMI) had no significant correlation with peakVO2 (P>0.05). Multivariate linear regression analysis showed that the HRI, SBPR were positively correlated with peakVO2(t=7.68, 5.08, respectively, all P<0.05), while age and BMI showed negative correlation with peakVO2(t=-5.43, -0.31, respectively, all P<0.05). PeakVO2 of male was higher than female(t=-6.03, P<0.05), and peakVO2 of HFrEF was lower than those of HFmrEF and HFpEF(t=3.17, 4.48, respectively, all P<0.05). A linear equation (F=33.52, adjusted R2=0.29) could be constructed: peakVO2=10.65(male) or 8.53(female)+4.26HRI+3.31SBPR-0.07age-0.13BMI+0(HFrEF) or 1.05 (HFmrEF) or 1.62(HFpEF). Conclusion: HRI and SBPR are positively correlated with peakVO2. In the absence of gas analysis, it is possible to apply HRI and SBPR during exercise to predict exercise tolerance in patients with CHF.