PON1 and myocardial infarction: Our data may support hypothesis that PON1 activity changes during myocardial infarct (or its experimental model: cardiac surgery) occur dynamically as a result of processes accompanied with myocardial ischaemia and should not be contributed only to previous decline of PON1 activity associated with atherosclerosis, because we did not find any significant correlation between PON1 activity and clinical (class of angina symptoms) or angiografic (occurrence of left main artery lesions) severity of coronary heart disease.