Background: The aim of the present study was to determine whether the parameters of cardiac magnetic resonance imaging (CMRI) might correlate with early ST-segment resolution (STR) after primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction (STEMI).
Methods and results: CMRI was performed in 45 STEMI patients (age: 56.6+/-13.0 years) at 8.2+/-8.0 days (early phase) and 3.3+/-1.1 months (late phase) after successful PCI. CMRI parameters were compared between 2 groups: > or = 70% STR (group 1, n = 21) and < 70% STR (group 2, n = 24). Both groups had similar baseline characteristics, except for a higher frequency of > or = 2 myocardial blush grade and shorter pain-to-balloon time in group 1. Early-phase CMRI showed that persistent microvascular obstruction (PMO) (38.1% vs 91.7%, p < 0.001) occurred less frequently and the percent infarct mass against total left ventricular (LV) mass (17.7+/-8.7% vs 29.1+/-13.4%, p = 0.001) was smaller in group 1. Late-phase CMRI revealed a significant increase in LV end-diastolic volume (-1.5+/-8.7 vs 14.5+/-25.5 ml, p = 0.026) and reduced ejection fraction (55.0+/-9.9% vs 47.8+/-11.1%, p = 0.027) in group 2.
Conclusions: CMRI demonstrated that early STR might be related to PMO and infarct size, and predicts LV dysfunction and adverse LV remodeling. Also, early-phase CMRI findings are comparable to late-phase CMRI in association with early STR.