12-leads surface ECG After the procedure, at 90 min, a standard 12 leads ECG will be used for evaluating ST resolution both on single lead, showing maximal ST elevation, and on the sum of multiple leads, showing ST elevation on admission. Lack of ST resolution will be defined as an ST resolution <30%. Partial resolution as an ST resolution <70% but > 30%. The detailed analysis of ECG resolution has been described elsewhere. The core laboratory for intracoronary or surface ECG analysis will be the Catholic University of Rome.