The cardio-pulmonary continuum – interaction of heart and lung at the population level

Heart and lung diseases are common comorbidities. They share the same risk factors and in both, dyspnea is the main clinical symptom. Coronary artery disease is the main cause of death in patients with COPD. Cardiac biomarkers predict rehospitalization and mortality in patients with acute exacerbated COPD. Even at the population level, subclinical lung function alteration is associated with measurable changes in biomarkers of cardiac stress and necrosis.

Impairment of lung function may cause symptoms of heart failure (HF), although no cardiovascular or structural heart disease is present. Patients with COPD suffer more frequently from diastolic dysfunction. This has been explained by shortening of diastolic filling due to medication-induced tachycardia and hypoxemia. Because of the mechanical compression of the heart, an increase in emphysema was associated with a reduction in cardiac chamber size. Even at the population level, mild pulmonary impairment affects the left ventricular performance. A decrease of FEV1/FVC ratio was shown to be associated with a reduction in stroke volume even after exclusion of individuals with COPD. Additionally, moderately reduced FEV1 was shown to be related to an increased incidence of HF.

The impact of COPD on the heart has repeatedly been shown in the past. Recently published studies could extend these findings to the population level and thus underline the close interaction of heart and lung.