“…The mechanisms responsible for the relationship between spirometric measurements and mortality in TOF and Fontan patients remain undefined. Past investigators, when noting a correlation between spirometric abnormalities and cardiovascular risk in the general population, have speculated that abnormal spirometric measurements reflect the presence of COPD which is, at least in part, an inflammatory disease process that may affect the cardiovascular system as well as the lungs . This explanation, initially proposed for patients with acquired heart disease, may apply to Fontan and TOF patients as well.…”