Abstract 2998: Prognostic Characteristics of Heart Rate Recovery According to Sex in Patients With Heart Failure
Introduction: Heart rate recovery (HRR) is emerging as an important prognostic marker in patients with heart failure (HF). Previous research suggests autonomic regulation differs between males and females and that HRR better reflects cardiovascular health in the latter gender.
Hypothesis: We hypothesize that HRR will provide superior prognostic resolution in female compared to male patients with HF.
Methods: Four hundred and ninety-four males (Age: 59.1±12.4 years, ejection fraction: 35.0±13.4%, 55% ischemic HF) and 128 females (Age: 56.4±12.6 years, ejection fraction: 34.6±12.9%, 41% ischemic HF) underwent cardiopulmonary exercise testing to determine peak oxygen consumption (VO2), percent-predicted peak VO2 (Wasserman), ventilatory efficiency (VE/VCO2 slope) and HRR at one minute (HRR1). Subjects were subsequently tracked for major cardiac events for three years.
Results: Peak VO2 was significantly higher in male subjects (17.7±6.4 vs. 13.6±4.2 mlO2•kg−1•min−1, p<0.001) while percent-predicted values were comparable (63.0±23.3 vs. 62.0±21.9%, p=0.69). HRR1 was significantly higher (18.8±12.1 vs. 15.6±9.3 bpm, p=0.005) while the VE/VCO2 slope (33.1±8.4 vs. 36.6±8.7, p<0.001) was significantly lower in male compared to female subjects. There were 70 (63 deaths, 6 transplants and 1 LVAD) and 25 (19 deaths, 5 transplants and 1 LVAD) major cardiac events in the male and female groups, respectively. Receiver operating characteristic curve analysis revealed the HRR1 prognostic classification schemes were significant for both male (area: 0.72, 95% CI: 0.65– 0.78, p<0.001) and female (area: 0.82, 95% CI: 0.75– 0.89, p<0.001) groups. By multivariate Cox regression, the VE/VCO2 slope was the strongest prognostic marker in males (Chi-square: 60.8, p<0.001) while HRR1 (Residual chi-square: 9.9, p=0.002) and peak VO2 (Residual chi-square: 5.0, p=0.03) added value. Conversely, HRR1 (Chi-square: 16.1, p<0.001) was the strongest prognostic marker in female subjects and only the VE/VCO2 slope (Residual chi-square: 9.2, p=0.002) was retained.
Conclusions: The prognostic strength of HRR may be superior in female patients with HF. This discrepancy may be driven by the ability of HRR to better reflect cardiovascular function in females.