Integrated heart rate and oxygen uptake recovery phenotypes reveal heterogeneous recovery patterns in coronary artery disease.

INTRODUCTION

Heart rate recovery (HRR) and oxygen uptake (VO₂) recovery provide complementary information regarding autonomic and metabolic recovery following exercise; however, their integrated assessment remains insufficiently explored in patients with coronary artery disease (CAD).

METHODS

This retrospective observational study included 200 patients with stable CAD who underwent symptom-limited cardiopulmonary exercise testing (CPET). HRR at 1 min (HRR1), ΔVO₂ values, and VO₂ recovery indices were analyzed, and patients were classified according to combined HRR and VO₂ recovery patterns using a 2 × 2 recovery framework.

RESULTS

HRR1 was significantly correlated with ΔVO₂1 (r = 0.519, p < 0.001) and ΔVO₂2 (r = 0.510, p < 0.001), as well as VO₂ recovery indices at 1 and 2 min (r = 0.496 and 0.531, respectively; both p < 0.001). Distinct concordant and discordant recovery phenotypes were identified, indicating heterogeneity in post-exercise recovery dynamics. Significant differences were observed across recovery groups, including significantly lower VO₂ recovery in the Good HRR-Poor VO₂ phenotype compared with the Poor HRR-Good VO₂ phenotype (p = 0.027).

DISCUSSION: Post-exercise recovery in CAD appears to be a multidimensional physiological process that cannot be fully characterized by a single parameter. Integrated assessment of HRR and VO₂ recovery may provide a framework for recovery characterization before cardiac rehabilitation, and prospective studies are needed to validate the clinical applicability of this approach.