Regional functional recovery after acute myocardial infarction: a cardiac magnetic resonance long-term study

We sought to analyze the trend of functional recovery after successful reperfused ST-elevation myocardial infarction (STEMI) in an optimally treated patient group over a 14 month follow-up in relation to ischemia-time and the presence of microvascular obstruction (MVO). First-pass perfusion-, cine- and late enhancement (LE)- cardiac MR were performed in 40 patients (33 male and 7 female, 54.8 ± 12.3 years) within 6 days as well as 4 and 14 months after successful primary percutaneous coronary intervention for STEMI. Significant recovery of segmental wall thickening (SWT %) occurred exclusively in infarcted segments reperfused within 4 h after symptom onset (group 1 with pain-to-balloon time <2 h: 59 ± 4 to 70 ± 4%; P < 0.02) (group 2 with pain-to-balloon-time 2-4 h: 51 ± 4 to 59 ± 3%, P < 0.05) during the first 4 months, whereas changes thereafter were not significant (P = NS). Infarcted segments with MVO showed lowest regional myocardial function at any time of assessment (all P < 0.001) and a lack of significant recovery during the study period. Significant recovery of regional myocardial function is related to rapid revascularization of the infarct-related artery and the absence of MVO. Improvement of SWT occurred exclusively within the first 4 months after acute myocardial infarction and remained unchanged thereafter.