Dynamic hyperinflation, chronotropic intolerance and abnormal heart rate recovery in non-severe chronic obstructive pulmonary disease patients-reflections in the mirror

BACKGROUND: The presence of abnormal heart rate recovery (HRR) and chronotropic incompetence (CI) suggests autonomic dysfunction (AD) and is associated with diminished physical activity and increased cardio-vascular (CV) risk. AIM: Our aim is to analyse the correlation between AD and airflow obstruction - forced expiratory volume in 1s (FEV1), dynamic hyperinflation (DH) and disease prognosis - the BODE ... index (BMI; Obstruction ... FEV1;Dyspnea ... mMRC;E ... exercise capacity) in non-severe COPD patients without overt CV comorbidities. METHODS: We used cardio-pulmonary exercise testing (CPET) with 67 subjects. Inspiratory capacity (IC) manouevres were performed for DH assessment. Echocardiography was executed before CPET and 1...2min after peak exercise. Stress left ventricular diastolic dysfunction (LVDD) was assumed if stress E/e...>15.Wilkoff method calculated the metabolic-chronotropic relationship (MCR). Chronotropic incompetence (CI) and abnormal HR recovery (HRR) were determined. MAIN RESULTS: CI was detected in 44% of the mild and 65% of the moderate COPD patients. Abnormal HRR was present in 75% of the mild and 78% of the moderate COPD subjects. Multivariate regression analysis showed no association between FEV1, CPET parameters, BODE index, stress LVDD and AD. DH was the only independent predictor for both abnormal HRR and CI. CONCLUSION: Evaluation of AD during incremental CPET unravels lung hyperinflation as a potential mechanism of attenuated HR response and diminished physical activity in non-severe COPD free of overt CV comorbidities. This multifaceted approach to dyspnea may facilitate the discrimination of its pathogenesis and improve its proper clinical management.