Cardiac Magnetic Resonance Evaluation of the Extent of Myocardial Injury in Patients with Inferior ST Elevation Myocardial Infarction and Concomitant ST Depression in Leads V1-V3: Analysis from the MITOCARE Study.

The aim of our study was to examine the pathophysiology of ST depression (STD) in leads V1-V3 in the setting of inferior ST elevation myocardial infarction (iSTEMI) through the perspective of cardiac magnetic resonance (CMR).

METHODS: Differences in myocardial area at risk (MaR), infarct size, ejection fraction and myocardial segment involvement by CMR were compared in MITOCARE trial patients with first iSTEMI with ST elevation (STE), STD or no ST changes (NST) in V1-V3. The frontal plane projection of the inferior wall MaR in relationship to the anterior/posterior chest wall was calculated and compared between groups.

RESULTS: Fifty-six patients were included. Patients with STD (n = 38) and STE (n = 5) in V1-V3 had significantly larger mean MaR compared to NST (n = 13; 32 ± 7%LV, 36 ± 10%LV and 26 ± 6%LV, respectively; p = 0.01). STD in leads V1-V3 was associated with more apical inferior and mid inferoseptal involvement and had a larger mean frontal plane projection of MaR compared with NST (24 ± 6%LV vs. 20 ± 6%LV, p = 0.04).

CONCLUSION: STD in V1-V3 in iSTEMI is associated with larger MaR, more extension into the inferoseptal segments and likely results from greater frontal plane projection of the MaR, leading to reciprocal changes on the electrocardiogram.