Chronotropic Incompetence and Abnormal Heart Rate Recovery in COPD: Relationship with Pulmonary Vascular Volume and Ventilatory Efficiency

Background: Cardiac automatic dysfunction (AD) is an established predictor of long-term mortality in patients with cardiopulmonary disease. It has been closely linked to lung blood perfusion abnormalities in pulmonary hypertension, a phenomenon that has been poorly studied in chronic obstructive pulmonary disease (COPD). This study aimed to 1) characterize computed tomography (CT), spirometry, and cardiopulmonary exercise test (CPET) features of COPD patients with cardiac AD; and 2) estimate the association of AD with CT-derived vascular and CPET-derived ventilatory efficiency metrics. Methods: Patients were randomly recruited and underwent clinical evaluation, spirometry, CPET, and CT. Cardiac AD was determined based on chronotropic incompetence (CI) or delayed heart rate recovery (HRR) during CPET. Results: Among 46 patients included in the study, CI was observed in 59% and delayed HRR was present in 35%. According to multivariate analyses, patients with CI were more likely to have reduced vascular volume (VV; VV < median; odds ratio [5–95% confidence interval], 4.82 [1.17–19.80]) and low ventilatory efficiency (nadir VE/VCO 2 > median ; odds ratio [5–95% confidence interval], 6.89 [1.57–30.20]). Similar results were found for delayed HRR (VV < median; odds ratio [5–95% confidence intervals], 13.45 [1.95–92.85], nadir VE/VCO 2 > median; odds ratio [5–95% confidence interval], 12.33 [1.56–97.30]). Conclusions: Cardiac AD is associated with increased pulmonary vascular volume and ventilatory efficiency. Findings suggest that lung blood perfusion abnormalities may occur in these patients, a result that requires confirmation via the assessment of a large population-based cohort.