Prognostic value of combined assessment of heart rate rise and recovery during cardiopulmonary exercise test on clinical outcomes in patients with chronic heart failure

Backgrounds Heart rate (HR) response during exercise is associated with morbidity and mortality in patients with heart failure (HF). In particular, HR recovery, the capacity to decrease HR following exercise, is well known as an indicator of clinical outcomes in patients with HF. However, the usefulness of a combined assessment of HR rise, time-based heart rate changes from rest to peak and from peak to the recovery phase, and HR recovery for outcome prediction remains unclear. Purpose We sought to investigate the association of HR rise and recovery during exercise with clinical outcomes in patients with HF. Methods We retrospectively examined 562 consecutive patients with chronic HF referred to cardiopulmonary exercise test (CPET) in our hospital between January 2013 and December 2021. We excluded those without achieving adequate stress (R < 1.05) and those dependent on cardio implantable electronic devices pacing during CPET. Patients were divided into four groups according to the median value of HR rise ([peak HR-rest HR]/[peak time-rest time]: 7.2bpm/min) and HR recovery ([peak HR-recovery HR]/[recovery time-peak time]: 10.3 bpm/min). The primary outcome was a composite of all-cause death or hospitalization due to worsening HF. Results Patients were classified into four groups; low HR rise and low HR recovery (n = 216, 38.4%), high HR rise and low HR recovery (n = 63, 11.2%), low HR rise and high HR recovery (n = 65, 11.6%), and high HR rise and high HR recovery (n = 218, 38.8%). Patients with low HR rise and low HR recovery group were older, had a higher prevalence of ischemic cardiomyopathy, diabetes mellitus and anemia, and higher prescription rate of beta-blockers compared to those with other groups. During a median follow-up period of 3.93 years (interquartile range 1.65–6.39), the primary outcome occurred in 111 patients. Patients with low HR rise and low HR recovery had the highest incidence of the primary outcome among the groups (P < 0.001, Figure 1). In a multivariable Cox regression analysis, low HR rise and low HR recovery was independently associated with a higher risk of the primary outcome after adjustment for significant prognostic covariates (hazard ratio 1.84; 95% confidence interval 1.11–3.05, P = 0.018, Figure 2). Conclusions In patients with HF, low HR rise and low HR recovery during exercise was independently associated with a higher risk of adverse events, suggesting that the combined assessment of HR rise and HR recovery during CPET is useful for the risk stratification.