This is a prospective study to determine the relationships between pauci-inflammatory exacerbations and diastolic dysfunction, and their implications in hospitalized patients with acute exacerbations of COPD. To assess changes within subjects from stable to acute phase, a number of comparisons will be made in subjects enrolled during acute exacerbation with similar measurements made in the stable phase after recovery from exacerbation after at least 35 days from index hospitalization or prior exacerbation.