Infarct remodeling process during long-term follow-up after reperfused acute myocardial infarction

After acute myocardial infarction (AMI), the recovery of perfusion in infarct area may lead to significant spontaneous infarct size (IS) reduction during the subsequent period. The natural course of infarct-healing process after reperfusion therapy has not been fully elucidated. In this study, we investigated the time course of the spontaneous infarct-healing process in patients with reperfused AMI.

Fifty-two patients with AMI who underwent primary percutaneous intervention were included. IS was measured with single-photon emission tomography using Bull's eye method at 4th day, at 5th, and at 10th months. IS was expressed as a percentage of the total myocardium. IS decreased by 33.6% at 5th month when compared with 4th day IS (from 26.3% +/- 18.8% to 17.5% +/- 12.9%, P < 0.001, n = 44). At 10th month, mean IS decreased by 21% when compared with 5th month IS (from 15.89% +/- 12.65% to 12.53% +/- 9.35%, P = 0.007, n = 31) and 49% when compared with 4th day IS (24.02% +/- 17.67% to 12.53% +/- 9.35%, P < 0.001).

Significant endogenous recovery of perfusion in the infarct area occurs at the long term in patients with reperfused AMI. Infarct healing is a dynamic and ongoing process and decrease in IS continues long term after reperfused AMI.