Outside of the standard ECG findings which are diagnostic of a STEMI previously mentioned, there is currently only one universally recognized “STEMI equivalent,” which is a left bundle branch block (LBBB) meeting the Sgarbossa’s criteria.19
There are other highly concerning ECG patterns that include the de Winter pattern, the left main pattern, hyperacute T waves, Wellen’s syndrome and posterior MI. These patterns are not considered a STEMI equivalent but emergent/urgent revascularization with PCI that should be considered.24 ECG interpretation may be complex and urgent teleconsultation with a cardiologist should be considered. ECG changes that should also raise concern for ischemia include ST depressions ≥ 0.5 mm (in ≥ 2 contiguous leads) or T-wave inversion.
1. LBBB with Sgarbossa’s criteria – Sgarbossa’s criteria was developed to identify an acute MI in the setting of a LBBB since this pattern can cause ST- and T-wave changes that make it difficult to identify an MI. The ECG is considered consistent with MI if any of the following three criteria are met and combine to equal ≥ 3 points:25
2. Modified Sgarbossa criteria (listed below) may outperform the original proposed criteria.26 Any of the changes listed below are diagnostic of MI in the modified criteria.